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Sample records for acrylic acid paa

  1. Acrylic acid

    Integrated Risk Information System (IRIS)

    Acrylic acid ( CASRN 79 - 10 - 7 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Eff

  2. Poly(aspartic acid) (PAA) hydrolases and PAA biodegradation: current knowledge and impact on applications.

    PubMed

    Hiraishi, Tomohiro

    2016-02-01

    Thermally synthesized poly(aspartic acid) (tPAA) is a bio-based, biocompatible, biodegradable, and water-soluble polymer that has a high proportion of β-Asp units and equivalent moles of D- and L-Asp units. Poly(aspartic acid) (PAA) hydrolase-1 and hydrolase-2 are tPAA biodegradation enzymes purified from Gram-negative bacteria. PAA hydrolase-1 selectively cleaves amide bonds between β-Asp units via an endo-type process, whereas PAA hydrolase-2 catalyzes the exo-type hydrolysis of the products of tPAA hydrolysis by PAA hydrolase-1. The novel reactivity of PAA hydrolase-1 makes it a good candidate for a biocatalyst in β-peptide synthesis. This mini-review gives an overview of PAA hydrolases with emphasis on their biochemical and functional properties, in particular, PAA hydrolase-1. Functionally related enzymes, such as poly(R-3-hydroxybutyrate) depolymerases and β-aminopeptidases, are compared to PAA hydrolases. This mini-review also provides findings that offer an insight into the catalytic mechanisms of PAA hydrolase-1 from Pedobacter sp. KP-2. PMID:26695157

  3. Rapid 3D Patterning of Poly(acrylic acid) Ionic Hydrogel for Miniature pH Sensors.

    PubMed

    Yin, Ming-Jie; Yao, Mian; Gao, Shaorui; Zhang, A Ping; Tam, Hwa-Yaw; Wai, Ping-Kong A

    2016-02-17

    Poly(acrylic acid) (PAA), as a highly ionic conductive hydrogel, can reversibly swell/deswell according to the surrounding pH conditions. An optical maskless -stereolithography technology is presented to rapidly 3D pattern PAA for device fabrication. A highly sensitive miniature pH sensor is demonstrated by in situ printing of periodic PAA micropads on a tapered optical microfiber.

  4. Synthesis and characterization of amylose grafted poly(acrylic acid) and its application in ammonia adsorption.

    PubMed

    Chen, Qing; Yu, Haojie; Wang, Li; Abdin, Zain-Ul; Yang, Xinpeng; Wang, Junhua; Zhou, Weidong; Zhang, Hongtao; Chen, Xiao

    2016-11-20

    Amylose grafted poly(acrylic acid) (Am-g-PAA) was synthesized by graft copolymerization of amylose with acrylic acid. The structure of Am-g-PAA was confirmed by (1)H NMR and FT-IR spectra. The morphology, crystallinity and thermal properties of amylose and Am-g-PAA were investigated by SEM, XRD and TGA, respectively. The highest degree of substitution (DS) of carboxyl group was 1.96 which was obtained after reacted for 1h at 60°C. Acrylic acid to anhydroglucose mole ratio for DS was 19.81. It was found that a large number of carboxyl groups were grafted on the backbone of amylose. It was also found that ammonia adsorption capacity of amylose increased by grafting poly(acrylic acid) on the backbone of amylose. PMID:27561514

  5. Influence of Glyoxal on Preparation of Poly(Vinyl Alcohol)/Poly(Acrylic Acid) Blend Film.

    PubMed

    Park, Ju-Young; Hwang, Kyung-Jun; Yoon, Soon-Do; Lee, Ju-Heon; Lee, In-Hwa

    2015-08-01

    The preparation of a poly(vinyl alcohol)/poly(acrylic acid)/glyoxal film (PVA = poly(vinyl alcohol); PAA = poly(acrylic acid)) with high tensile strength and hydrophobic properties by using the crosslinking reaction for OH group removal is reported herein. PAA was selected as a crosslinking agent because the functional carboxyl group in each monomer unit facilitates reaction with PVA. The OH groups on unreacted PVA were removed by the addition of glyoxal to the PVA/PAA solution. The chemical properties of the PVA/PAA films were investigated using Fourier transformation infrared spectroscopy and the thermal properties of the PVA/PAA/glyoxal films were investigated by means of differential scanning calorimetry and thermogravimetric analysis. A tensile strength of 48.6 N/mm2 was achieved at a PVA/PAA ratio of 85/15 for the PVA/PAA film. The tensile strength of the cross-linked PVA/PAA/glyoxal film (10 wt% glyoxal) was increased by 55% relative to the pure PVA/PAA (85/15) film. The degree of swelling (DS) and solubility (S) of the 10 wt% (PVA/PAA = 85/15, wt%) film added 10 wt% glyoxal were 1.54 and 0.6, respectively. PMID:26369179

  6. Antimicrobial activity of poly(acrylic acid) block copolymers.

    PubMed

    Gratzl, Günther; Paulik, Christian; Hild, Sabine; Guggenbichler, Josef P; Lackner, Maximilian

    2014-05-01

    The increasing number of antibiotic-resistant bacterial strains has developed into a major health problem. In particular, biofilms are the main reason for hospital-acquired infections and diseases. Once formed, biofilms are difficult to remove as they have specific defense mechanisms against antimicrobial agents. Antimicrobial surfaces must therefore kill or repel bacteria before they can settle to form a biofilm. In this study, we describe that poly(acrylic acid) (PAA) containing diblock copolymers can kill bacteria and prevent from biofilm formation. The PAA diblock copolymers with poly(styrene) and poly(methyl methacrylate) were synthesized via anionic polymerization of tert-butyl acrylate with styrene or methyl methacrylate and subsequent acid-catalyzed hydrolysis of the tert-butyl ester. The copolymers were characterized via nuclear magnetic resonance spectroscopy (NMR), size-exclusion chromatography (SEC), Fourier transform infrared spectroscopy (FTIR), elemental analysis, and acid-base titrations. Copolymer films with a variety of acrylic acid contents were produced by solvent casting, characterized by atomic force microscopy (AFM) and tested for their antimicrobial activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. The antimicrobial activity of the acidic diblock copolymers increased with increasing acrylic acid content, independent of the copolymer-partner, the chain length and the nanostructure.

  7. Nanoparticles of Block Ionomer Complexes from Double Hydrophilic Poly(acrylic acid)- b-poly(ethylene oxide)- b-poly(acrylic acid) Triblock Copolymer and Oppositely Charged Surfactant

    NASA Astrophysics Data System (ADS)

    Peng, Zhiping; Sun, Yuelong; Liu, Xinxing; Tong, Zhen

    2010-01-01

    The novel water-dispersible nanoparticles from the double hydrophilic poly(acrylic acid)- b-poly(ethylene oxide)- b-poly(acrylic acid) (PAA- b-PEO- b-PAA) triblock copolymer and oppositely charged surfactant dodecyltrimethyl ammonium bromide (DTAB) were prepared by mixing the individual aqueous solutions. The structure of the nanoparticles was investigated as a function of the degree of neutralization (DN) by turbidimetry, dynamic light scattering (DSL), ζ-potential measurement, and atomic force microscope (AFM). The neutralization of the anionic PAA blocks with cationic DTAB accompanied with the hydrophobic interaction of alkyl tails of DTAB led to formation of core-shell nanoparticles with the core of the DTAB neutralized PAA blocks and the shell of the looped PEO blocks. The water-dispersible nanoparticles with negative ζ-potential were obtained over the DN range from 0.4 to 2.0 and their sizes depended on the DN. The looped PEO blocks hindered the further neutralization of the PAA blocks with cationic DTAB, resulting in existence of some negative charged PAA- b-PEO- b-PAA backbones even when DN > 1.0. The spherical and ellipsoidal nature of these nanoparticles was observed with AFM.

  8. Acute toxicity of peracetic acid (PAA) to fish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA; also called peroxyacetic acid) is a promising new aquatic disinfectant that has also been used to treat parasites and fungus. It is registered with the U.S. Environmental Protection Agency (EPA) as an antimicrobial compound approved for indoor use on hard, non-porous surfaces. T...

  9. Intercalation of acrylic acid and sodium acrylate into kaolinite and their in situ polymerization

    NASA Astrophysics Data System (ADS)

    Zhang, Bo; Li, Yanfeng; Pan, Xiaobing; Jia, Xin; Wang, Xiaolong

    2007-02-01

    Novel nano-composites of poly (acrylic acid)-kaolinite were prepared, and intercalation and in situ polymerization were used in this process. The nano-composites were obtained by in situ polymerization of acrylic acid (AA) and sodium acrylate (AANa) intercalated into organo-kaolinite, which was obtained by refining and chemically modifying with solution intercalation step in order to increase the basal plane distance of the original clay. The modification was completed by using dimethyl-sulfoxide (DMSO)/methanol and potassium acetate (KAc)/water systems step by step. The materials were characterized with the help of XRD, FT-IR and TEM; the results confirmed that poly(acrylic acid) (PAA) and poly(sodium acrylate) (PAANa) were intercalated into the interlamellar spaces of kaolinite, the resulting copolymer composites (CC0 : copolymer crude kaolinite composite, CC1 : copolymer DMSO kaolinite composite, CC2 : copolymer KAc kaolinite composite) of CC2 exhibited a lamellar nano-composite with a mixed nano-morphology, and partial exfoliation of the intercalating clay platelets should be the main morphology. Finally, the effect of neutralization degree on the intercalation behavior was also investigated.

  10. Influence of ozone and paracetic acid disinfection on adhesion of resilient liners to acrylic resin

    PubMed Central

    2016-01-01

    PURPOSE The aim of this study was to evaluate the effect of paracetic acid (PAA) and ozone disinfection on the tensile bond strength (TBS) of silicone-based resilient liners to acrylic resins. MATERIALS AND METHODS One hundred and twenty dumbbell shaped heat-polymerized acrylic resins were prepared. From the mid segment of the specimens, 3 mm of acrylic were grinded off and separated parts were reattached by resilient liners. The specimens were divided into 2 control (control1, control7) and 4 test groups of PAA and ozone disinfection (PAA1, PAA7, ozone1 and ozone7; n=10). While control groups were immersed in distilled water for 10 min (control1) and 7 days (control7), test groups were subjected to PAA (16 g/L) or ozone rich water (4 mg/L) for 1 cycle (10 min for PAA and 60 min for ozone) per day for 7 days prior to tensile tests. Measurements of the TBS were analyzed using 3-way ANOVA and Tukey's HSD test. RESULTS Adhesive strength of Mollosil decreased significantly by application of ozone disinfection. PAA disinfection had no negative effect on the TBS values of Mollosil and Molloplast B to acrylic resin. Single application of ozone disinfection did not have any negative effect on TBS values of Molloplast B, but prolonged exposure to ozone decreased its adhesive strength. CONCLUSION The adhesion of resilient liners to acrylic was not adversely affected by PAA disinfection. Immersion in ozonated water significantly decreased TBS of Mollosil. Prolonged exposure to ozone negatively affects adhesion of Molloplast B to denture base materials. PMID:27555898

  11. Swelling behaviors of porous lignin based poly (acrylic acid).

    PubMed

    Ma, Yanli; Sun, Yajie; Fu, Yujie; Fang, Guizhen; Yan, Xingru; Guo, Zhanhu

    2016-11-01

    Supramolecular cross-linked porous lignin based poly (acrylic acid) [LBPAA] was lab-synthesized by copolymerizing lignin grafted N, N'-methylene-bisacrylamide (LM) and acrylic acid. LBPAA successfully acted as a water retention agent with salt resistance and biodegradation for agricultural applications. Lignin was found to improve its swelling behaviors with higher water retention, fast swelling and de-swelling rates. The salt tolerance was stronger in the case of LBPAA (60 PAA/40 LM) [60 wt% PAA/40 wt% LM], i.e., 145.79 g·g(-1) higher than PAA at 0.09 mM KCl solution. The effect of ion charges on the LBPAA swelling ratio was greater than that of ionic radius. The weight loss of LBPAA (60 PAA/40 LM) was 5.47%, 4.96%, and 4.56% in the soil of Tangshan, Harbin, and Sian, respectively. The soil moisture content and clay content were observed to decrease gradually with increasing the burial time. The biodegradation test of LBPAA (60 PAA/40 LM) composite exhibited different bacterial colony forming units (CFU), the soil of Tangshan was 2.0 × 10(3) CFU·g(-1) soil, 7.0 × 10(3) CFU·g(-1) soil for Harbin, and 6.10 × 10(4) CFU·g(-1) soil for Sian. However, the organic matter contents in the soils did not have significant changes (Tangshan 6.21 mg·g(-1), Harbin 0.61 mg·g(-1), and Sian 0.405 mg·g(-1)). PMID:27587327

  12. Self-Assembly of Amphiphilic Block Copolymers Containing Poly(n-octadecyl acrylate) Block in Aqueous Solution

    NASA Astrophysics Data System (ADS)

    Akiba, Isamu; Akino, Yusuke; Masunaga, Hiroyasu; Sakurai, Kazuo

    2010-11-01

    Synchrotron small-angle X-ray scattering (SAXS) experiments were carried out for poly(acrylic acid)-block-poly(n-octadecyl acrylate) (PAA-b-PODA) and PAA-b-PODA-b-PAA micelles in aqueous solutions. SAXS results indicated that PAA-b-PODA and PAA-b-PODA-b-PAA formed core-shell micelles with disk-like morphology below melting temperature of PODA in aqueous solutions. The thickness of PAA-b-PODA (diblock copolymer) micelle was larger than that of PAA-b-PODA-b-PAA (triblock copolymer) micelle. The difference of sizes between these micelles was related to difference of molecular architectures of PAA-b-PODA and PAA-b-PODA-b-PAA. PAA-b-PODA micelle showed morphological transition from disk to spherical shape with elevating temperature. On the contrary, PAA-b-PODA-b-PAA micelle maintained disk-like shape above melting temperature, although enlargement of micelle thickness is caused.

  13. Controlled Transdermal Iontophoresis by Polypyrrole/Poly(Acrylic Acid) Hydrogel

    NASA Astrophysics Data System (ADS)

    Chansai, Phithupha; Sirivat, Anuvat

    2008-03-01

    Transdermal drug delivery system delivers a drug into a body at desired site and rate. The conductive polymer-hydrogel blend between polypyrrole (PPy) doped with anionic drug and poly(acrylic acid) (PAA) were developed as a matrix/carrier of drug for the transdermal drug delivery in which the characteristic releases depend on the electrical field applied. The PAA films and their blend films were prepared by solution casting using ethylene glycol dimethacrylate (EGDMA) as a crosslinking agent. A mechanical blending of PPy particles and PAA matrix was then carried out. Drug diffusions in the blended PPy/PAA hydrogel and the non-blended one were investigated and determined by using a modified Franz-diffusion cell with an acetate buffer, pH 5.5, at 37 0C, for a period of 48 hours to determine the effects of crosslinking ratio and electric field strength. Amounts of the released drug were measured by UV-Visible spectrophotometry. The diffusion coefficient of drug was determined through the Higuchi equation via different conditions, with and without an electric field. Moreover, thermal properties and electrical conductivity of the polypyrrole and drug-loaded polypyrrole were investigated by means of the thermogravimetric analysis and by using a two-point probe meter, respectively.

  14. Enzyme immobilization on ultrafine cellulose fibers via poly(acrylic acid) electrolyte grafts.

    PubMed

    Chen, Hong; Hsieh, You-Lo

    2005-05-20

    Ultrafine cellulose fiber (diameter 200-400 nm) surfaces were grafted with polyacrylic acid (PAA) via either ceric ion initiated polymerization or methacrylation of cellulose with methacrylate chloride (MACl) and subsequent free-radical polymerization of acrylic acid. PAA grafts by ceric ion initiated polymerization increased with increasing reaction time (2-24 h), monomer (0.3-2.4 M), and initiator (1-10 mM) concentrations, and spanned a broad range from 5.5-850%. PAA grafts on the methacrylated cellulose fibers also increased with increasing molar ratios of MACl to cellulosic hydroxyl groups (MACl/OH, 2-6.4) and monomer acrylic acid (AA) to initiator potassium persulfate (KPS) ratios ([AA]/[KPS], 1.5-6), and were in a much narrower range between 12.8% and 29.4%. The adsorption of lipase (at 1 mg/ml lipase and pH 7) and the activity of adsorbed lipase (pH 8.5, 30 degrees C), in both cases decreased with increasing PAA grafts. The highest adsorption and activity of the lipase on the ceric ion initiated grafted fibers were 1.28 g/g PAA and 4.3 U/mg lipase, respectively, at the lowest grafting level of 5.5% PAA, whereas they were 0.33 g/g PAA and 7.1 U/mg lipase, respectively, at 12.8% PAA grafts on the methacrylated and grafted fibers. The properties of the grafted fibers and the absorption behavior and activity of lipase suggest that the PAA grafts are gel-like by ceric-initiated reaction and brush-like by methacrylation and polymerization. The adsorbed lipase on the ceric ion-initiated grafted surface possessed greatly improved organic solvent stability over the crude lipase. The adsorbed lipases exhibited 0.5 and 0.3 of the initial activity in the second and third assay cycles, respectively. PMID:15816022

  15. Preparation and Biophysical Characterization of Poly(amidoamine) Dendrimer-Poly(acrylic acid) Graft.

    PubMed

    Dung, Tran Huu; Do, Le Thanh; Loan, Ta Thi; Yoo, Hoon

    2015-01-01

    A series of PAMAM dendrimer generation 5-poly(acrylic acid) grafts were prepared to evaluate the potential use of dendritic grafts as a drug encapsulated nanocarrier. The structural features of the synthesized polymer graft were identified by FT-IR and 1H-NMR spectra and the biophysical properties were characterized by measuring its particle size and zeta potential. The prepared dendrimer G5-PAA grafts had particle size in the range of 600 to 900 nm and the size increased proportionally with the number of PAA on dendrimer surface. The electrostatic property of the dendrimer G5-PAA, carried out by HPLC reversed phase column analysis and the measurement of zeta potential, revealed that both migration time and zeta potential were dependent on the number of grafted PAA. The number of free amino groups on dendrimer G5-PAA, determined quantitatively by fluorescamine assay, was in a reverse order with the reaction mole ratio of dendrimer to PAA. In addition, dendrimer G5-PAA showed a pH-dependent solubility in aqueous solution with characteristic pH region of solubility, depending on the dendrimer generation. The observed biophysical properties indicate that PAMAM dendrimer G5-PAA is promising as a drug encapsulated nanocarrier. PMID:26328427

  16. Esterification of acrylic acid with methanol

    SciTech Connect

    Chubarov, G.A.; Danov, S.M.; Logutov, V.I.; Obmelyukhina, T.N.

    1984-01-01

    The esterification of acrylic acid with methanol in the absence of catalysis by strong mineral acids has been studied. The esterification rate was estimated from the amount of methyl acrylate formed at the end of a definite time, and the reaction rate was found to be first order with respect to methanol and second order with respect to acrylic acid. Mathematical relationships in good agreement with experimental data were derived from the results of the kinetic studies.

  17. pH- and Electro-Responsive Properties of Poly(acrylic acid) and Poly(acrylic acid)-block-poly(acrylic acid-grad-styrene) Brushes Studied by Quartz Crystal Microbalance with Dissipation Monitoring.

    PubMed

    Borisova, O V; Billon, L; Richter, R P; Reimhult, E; Borisov, O V

    2015-07-14

    We report on the synthesis of novel pH- and electro-responsive polyelectrolyte brushes from a gold substrate by direct one-step nitroxide-mediated polymerization of acrylic acid (AA) or copolymerization of AA and styrene (S). In the latter case, amphiphilic brushes of block-gradient copolymers PAA-b-(PAA-grad-PS) comprising one PAA block and one block with the gradient sequence of AA and S were obtained. The block-gradient copolymers are initiated from the surface by the start of the PAA block. The brushes were characterized by XPS and ellipsometry. (1)H NMR confirmed the gradient sequence of the PAA-grad-PS copolymer block. The pH- and electro-responsive properties of the brushes were studied by quartz crystal microbalance with dissipation monitoring (QCM-D) in combination with electrochemistry. This method provides evidence of swelling of the PAA brushes proportional to the contour length of the chains at elevated pH, whereas the response functions of the block-gradient copolymers are more complex and point to intermolecular aggregation in the brush at low pH. Monitoring of the changes in resonance frequency and dissipation of the QCM-D also demonstrates that application of negative voltage to the substrate leads to swelling of the brush; application of a positive voltage provokes only a transient collapse of the brush in proportion to the applied voltage. PMID:26070329

  18. pH- and Electro-Responsive Properties of Poly(acrylic acid) and Poly(acrylic acid)-block-poly(acrylic acid-grad-styrene) Brushes Studied by Quartz Crystal Microbalance with Dissipation Monitoring.

    PubMed

    Borisova, O V; Billon, L; Richter, R P; Reimhult, E; Borisov, O V

    2015-07-14

    We report on the synthesis of novel pH- and electro-responsive polyelectrolyte brushes from a gold substrate by direct one-step nitroxide-mediated polymerization of acrylic acid (AA) or copolymerization of AA and styrene (S). In the latter case, amphiphilic brushes of block-gradient copolymers PAA-b-(PAA-grad-PS) comprising one PAA block and one block with the gradient sequence of AA and S were obtained. The block-gradient copolymers are initiated from the surface by the start of the PAA block. The brushes were characterized by XPS and ellipsometry. (1)H NMR confirmed the gradient sequence of the PAA-grad-PS copolymer block. The pH- and electro-responsive properties of the brushes were studied by quartz crystal microbalance with dissipation monitoring (QCM-D) in combination with electrochemistry. This method provides evidence of swelling of the PAA brushes proportional to the contour length of the chains at elevated pH, whereas the response functions of the block-gradient copolymers are more complex and point to intermolecular aggregation in the brush at low pH. Monitoring of the changes in resonance frequency and dissipation of the QCM-D also demonstrates that application of negative voltage to the substrate leads to swelling of the brush; application of a positive voltage provokes only a transient collapse of the brush in proportion to the applied voltage.

  19. Hemocompatibility of Chitosan/poly(acrylic acid) Grafted Polyurethane Tubing

    PubMed Central

    Lee, Hyun-Su; Tomczyk, Nancy; Kandel, Judith; Composto, Russell J.; Eckmann, David M.

    2013-01-01

    The activation and adhesion of platelets or whole blood exposed to chitosan (CH) grafted surfaces is used to evaluate the hemocompatibility of biomaterials. The biomaterial surfaces are polyurethane (PU) tubes grafted with an inner poly(acrylic acid) (PAA) and an outer CH or quaternary ammonium modified CH (CH-Q) brush. The CH, CH-Q and PAA grafted layers were characterized by ellipsometry and fluorescence microscopy. Material wear tests demonstrate that CH (CH-Q) is stably grafted onto PU tubes upon exposure to saline solution for 7 days. Using quartz-crystal microbalances with dissipation (QCM-D), in-situ adsorption of blood plasma proteins on CH and CH-Q compared to a silicon oxide control was measured. The QCM-D results showed that the physically adsorbed plasma protein layer on CH-Q and CH surfaces is softer and more viscous than the protein layer on the SiO2 surface. The CH-Q layer thus has the weakest interaction with plasma proteins. Whole blood and platelet adhesion was reduced by ~92% on CH-Q, which showed the weakest interaction with plasma protein but more viscous adsorbed plasma protein layer, compared to SiO2. Last, to examine the biologic response of platelets and neutrophils to biomaterial surfaces, CH (CH-Q)/PAA, PAA and PU tubes were tested using a Chandler Loop apparatus as an ex vivo model and flow cytometry. The blood adhesion and biologic response results showed that CH and CH-Q reduced adhesion and activation of platelets and neutrophils and improved hemocompatibility relative to other surfaces (PU and PAA). Our studies demonstrated that the properties of physically adsorbed plasma protein layer on biomaterial surfaces correlates with blood coagulation on biomaterial surfaces. PMID:24349719

  20. Cellulose nanocrystal-filled poly(acrylic acid) nanocomposite fibrous membranes.

    PubMed

    Lu, Ping; Hsieh, You-Lo

    2009-10-14

    Nanocomposite fibrous membranes have been fabricated by electrospinning cellulose nanocrystal (CNC)-loaded poly(acrylic acid) (PAA) ethanol mixtures. Incorporating CNC in PAA significantly reduced fiber diameters and improved fiber uniformity. The average diameters of the as-spun nanocomposite fibers were significantly reduced from 349 nm to 162 nm, 141 nm, 90 nm and 69 nm at 5%, 10%, 15% and 20% CNC loading (by weight of a constant 4% PAA solution), respectively. CNC was well dispersed in the fibers as isolated rods oriented along the fiber axis and as spheres in the PAA matrix. The Young modulus and stress of the PAA/CNC nanocomposite fibers were significantly improved with increasing CNC loadings by up to 35-fold and 16-fold, respectively. Heat-induced esterification between the CNC surface hydroxyls and PAA carboxyl groups produced covalent crosslinks at the CNC-PAA interfaces, rendering the nanocomposite fibrous membranes insoluble in water, more thermally stable and far more superior in tensile strength. With 20% CNC, the crosslinked nanocomposite fibrous membrane exhibited a very impressive 77-fold increase in modulus and 58-fold increase in stress.

  1. Interaction of photosensitive surfactant with DNA and poly acrylic acid

    SciTech Connect

    Zakrevskyy, Yuriy Paasche, Jens; Lomadze, Nino; Santer, Svetlana; Cywinski, Piotr; Cywinska, Magdalena; Reich, Oliver; Löhmannsröben, Hans-Gerd

    2014-01-28

    In this paper, we investigate interactions and phase transitions in polyelectrolyte-surfactant complexes formed between a cationic azobenzene-containing surfactant and two types of polyelectrolytes: natural (DNA) or synthetic (PAA: poly acrylic acid). The construction of a phase diagram allowed distancing between four major phases: extended coil conformation, colloidally stable compacted globules, colloidal instability range, and surfactant-stabilized compact state. Investigation on the complexes’ properties in different phases and under irradiation with UV light provides information about the role of the surfactant's hydrophobic trans isomers both in the formation and destruction of DNA and PAA globules as well as in their colloidal stabilization. The trans isomer shows much stronger affinity to the polyelectrolytes than the hydrophilic cis counterpart. There is no need for complete compensation of the polyelectrolyte charges to reach the complete compaction. On contrary to the findings previously reported in the literature, we demonstrate – for the first time – complete polyelectrolyte compaction which occurs already at 20% of DNA (and at 50% of PAA) charge compensation. The trans isomer plays the main role in the compaction. The aggregation between azobenzene units in the photosensitive surfactant is a driving force of this process. The decompaction can be realized during UV light irradiation and is strongly influenced by the interplay between surfactant-surfactant and surfactant-DNA interactions in the compacted globules.

  2. Interaction of photosensitive surfactant with DNA and poly acrylic acid.

    PubMed

    Zakrevskyy, Yuriy; Cywinski, Piotr; Cywinska, Magdalena; Paasche, Jens; Lomadze, Nino; Reich, Oliver; Löhmannsröben, Hans-Gerd; Santer, Svetlana

    2014-01-28

    In this paper, we investigate interactions and phase transitions in polyelectrolyte-surfactant complexes formed between a cationic azobenzene-containing surfactant and two types of polyelectrolytes: natural (DNA) or synthetic (PAA: poly acrylic acid). The construction of a phase diagram allowed distancing between four major phases: extended coil conformation, colloidally stable compacted globules, colloidal instability range, and surfactant-stabilized compact state. Investigation on the complexes' properties in different phases and under irradiation with UV light provides information about the role of the surfactant's hydrophobic trans isomers both in the formation and destruction of DNA and PAA globules as well as in their colloidal stabilization. The trans isomer shows much stronger affinity to the polyelectrolytes than the hydrophilic cis counterpart. There is no need for complete compensation of the polyelectrolyte charges to reach the complete compaction. On contrary to the findings previously reported in the literature, we demonstrate - for the first time - complete polyelectrolyte compaction which occurs already at 20% of DNA (and at 50% of PAA) charge compensation. The trans isomer plays the main role in the compaction. The aggregation between azobenzene units in the photosensitive surfactant is a driving force of this process. The decompaction can be realized during UV light irradiation and is strongly influenced by the interplay between surfactant-surfactant and surfactant-DNA interactions in the compacted globules. PMID:25669583

  3. Energy Transfer of CdSe/ZnS Nanocrystals Encapsulated with Rhodamine-Dye Functionalized Poly(acrylic acid)

    PubMed Central

    Somers, Rebecca C.; Snee, Preston T.; Bawendi, Moungi G.; Nocera, Daniel G.

    2014-01-01

    Energy transfer between a CdSe/ZnS nanocrystal (NC) donor and a rhodamine isothiocyanate (RITC) acceptor has been achieved via a functionalized poly(acrylic acid) (PAA) encapsulating layer over the surface of the NC. The modification of PAA with both N-octylamine (OA) and 5-amino-1-pentanol (AP), [PAA-OA-AP], allows for the simultaneous water-solubilization and functionalization of the NCs, underscoring the ease of synthesizing NC-acceptor conjugates with this strategy. Photophysical studies of the NC-RITC constructs showed that energy transfer is efficient, with kFRET approaching 108 s−1. The ease of the covalent conjugation of molecules to NCs with PAA-OA-AP coating, together with efficient energy transfer, makes the NCs encapsulated with PAA-OA-AP attractive candidates for sensing applications. PMID:24926175

  4. Mechanistic approaches on the antibacterial activity of poly(acrylic acid) copolymers.

    PubMed

    Gratzl, Günther; Walkner, Sarah; Hild, Sabine; Hassel, Achim Walter; Weber, Hedda Katrin; Paulik, Christian

    2015-02-01

    The availability of polymeric antimicrobially active surfaces, which are mainly based on cationic surface effects, is limited. We have previously reported the discovery that, in addition to cationic surfaces, anionic surfaces based on poly(acrylic acid) (PAA) copolymers have a bactericidal effect. In this study, poly(styrene)-poly(acrylic acid)-diblock copolymers (PS-b-PAA) are used to describe the major variables causing the material to have a bactericidal effect on Escherichia coli ATCC 25922 in aqueous suspensions. Upon contact with water, the surface structure of the copolymer changes, the pH value decreases, and the PAA-block migrates toward the surface. Systematically modified antimicrobial tests show that the presence of acid-form PAA provides maximum antimicrobial activity of the material in slightly acidic conditions, and that an ion-exchange effect is the most probable mechanism. Antimicrobially inactive counter-ions inhibit the bactericidal activity of the copolymers, but the material can be regenerated by treatment with acids. PMID:25543987

  5. Mechanistic approaches on the antibacterial activity of poly(acrylic acid) copolymers.

    PubMed

    Gratzl, Günther; Walkner, Sarah; Hild, Sabine; Hassel, Achim Walter; Weber, Hedda Katrin; Paulik, Christian

    2015-02-01

    The availability of polymeric antimicrobially active surfaces, which are mainly based on cationic surface effects, is limited. We have previously reported the discovery that, in addition to cationic surfaces, anionic surfaces based on poly(acrylic acid) (PAA) copolymers have a bactericidal effect. In this study, poly(styrene)-poly(acrylic acid)-diblock copolymers (PS-b-PAA) are used to describe the major variables causing the material to have a bactericidal effect on Escherichia coli ATCC 25922 in aqueous suspensions. Upon contact with water, the surface structure of the copolymer changes, the pH value decreases, and the PAA-block migrates toward the surface. Systematically modified antimicrobial tests show that the presence of acid-form PAA provides maximum antimicrobial activity of the material in slightly acidic conditions, and that an ion-exchange effect is the most probable mechanism. Antimicrobially inactive counter-ions inhibit the bactericidal activity of the copolymers, but the material can be regenerated by treatment with acids.

  6. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acrylamide-acrylic acid resins. 176.110 Section... Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be...) Acrylamide-acrylic acid resins are produced by the polymerization of acrylamide with partial hydrolysis or...

  7. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin... acrylamide with partial hydrolysis, or by copolymerization of acrylamide and acrylic acid with the...

  8. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin... acrylamide with partial hydrolysis, or by copolymerization of acrylamide and acrylic acid with the...

  9. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin... acrylamide with partial hydrolysis, or by copolymerization of acrylamide and acrylic acid with the...

  10. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid resin... acrylamide with partial hydrolysis, or by copolymerization of acrylamide and acrylic acid with the...

  11. Sanitizing with peracetic acid (PAA)- An alternative treatment to use in aquaculture ...?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of the lack of approved treatments for fish disease, disinfectants were tested to treat fish pathogens. One of these substances is peracetic acid (PAA). PAA is an agent used for disinfection in aquaculture, but it must be investigated thoroughly in order to mitigate diseases without harmful ...

  12. Poly(acrylic acid) brushes pattern as a 3D functional biosensor surface for microchips

    NASA Astrophysics Data System (ADS)

    Wang, Yan-Mei; Cui, Yi; Cheng, Zhi-Qiang; Song, Lu-Sheng; Wang, Zhi-You; Han, Bao-Hang; Zhu, Jin-Song

    2013-02-01

    Poly(acrylic acid) (PAA) brushes, a novel three dimensional (3D) precursor layer of biosensor or protein microarrays, possess high protein loading level and low non-specific protein adsorption. In this article, we describe a simple and convenient way to fabricate 3D PAA brushes pattern by microcontact printing (μCP) and characterize it with FT-IR and optical microscopy. The carboxyl groups of PAA brushes can be applied to covalently immobilize protein for immunoassay. Thriving 3D space made by patterning PAA brushes thin film is available to enhance protein immobilization, which is confirmed by measuring model protein interaction between human immunoglobulin G (H-IgG) and goat anti-H-IgG (G-H-IgG) with fluorescence microscopy and surface plasmon resonance imaging (SPRi). As expected, the SPRi signals of H-IgG coating on 3D PAA brushes pattern and further measuring specific binding with G-H-IgG are all larger than that of 3D PAA brushes without pattern and 2D bare gold surface. We further revealed that this surface can be used for high-throughput screening and clinical diagnosis by label-free assaying of Hepatitis-B-Virus surface antibody (HBsAb) with Hepatitis-B-Virus surface antigen (HBsAg) concentration array chip. The linearity range for HBsAb assay is wider than that of conventional ELISA method.

  13. Nanoparticle Formation from Hybrid, Multiblock Copolymers of Poly(Acrylic Acid) and VPGVG Peptide

    PubMed Central

    Grieshaber, Sarah E.; Paik, Bradford A.; Bai, Shi; Kiick, Kristi L.; Jia, Xinqiao

    2012-01-01

    Elastin-mimetic hybrid copolymers with an alternating molecular architecture were synthesized via the step growth polymerization of azide-functionalized, telechelic poly(tert-butyl acrylate) (PtBA) and an alkyne-terminated, valine and glycine-rich peptide with a sequence of (VPGVG)2 (VG2). The resultant hybrid copolymer, [PtBA-VG2]n, contains up to six constituent building blocks and has a polydispersity index (PDI) of ~1.9. Trifluoroacetic acid (TFA) treatment of [PtBA-VG2]n gave rise to an alternating copolymer of poly(acrylic acid) (PAA) and VG2 ([PAA-VG2]n). The modular design permits facile adjustment of the copolymer composition by varying the molecular weight of PAA (22 and 63 repeat units). Characterization by dynamic light scattering indicated that the multiblock copolymers formed discrete nanoparticles at room temperature in aqueous solution at pH 3.8, with an average diameter of 250-270 nm and a particle size distribution of 0.34 for multiblock copolymers containing PAA22 and 0.17 for those containing PAA63. Upon increasing the pH to 7.4, both types of particles were able to swell without being disintegrated, reaching an average diameter of 285-300 nm for [PAA22-VG2]n and 330-350 nm for [PAA63-VG2]n, respectively. The nanoparticles were not dissociated upon the addition of urea, further confirming their unusual stability. The nanoparticles were capable of sequestering a hydrophobic fluorescent dye (pyrene), and the critical aggregation concentration (CAC) was determined to be 1.09 × 10-2 or 1.05 × 10-2 mg/mL for [PAA22-VG2]n and [PAA63-VG2]n, respectively. We suggest that the multiblock copolymers form through collective H-bonding and hydrophobic interactions between the PAA and VG2 peptide units, and that the unusual stability of the multiblock nanoparticles is conferred by the multiblock architecture. These hybrid multiblock copolymers are potentially useful as pH-responsive drug delivery vehicles, with the possibility of drug loading through

  14. Poly(acrylic acid)-poly(ethylene glycol) nanoparticles designed for ophthalmic drug delivery.

    PubMed

    Vasi, Ana-Maria; Popa, Marcel Ionel; Tanase, Edi Constantin; Butnaru, Maria; Verestiuc, Liliana

    2014-02-01

    Poly(acrylic acid) (PAA) and poly(ethylene glycol) (PEG), four-arm, amine-terminated particles with nanometer size and spherical shape were obtained by the polymers cross-linking, via activation with 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide hydrochloride, in a w/o emulsion. The morphology and surface charge of the final particles are strongly dependent on the molar ratio of PAA-PEG and the PAA concentration. The physicochemical characteristics correlated with the drug-loading capacity, in vitro and ex vivo release kinetics of pilocarpine hydrochloride and biocompatibility results indicate that these nanoparticles exhibit the prerequisite behavior for use as carriers of ophthalmic drugs. PMID:24357331

  15. Electrophoretic Mobility of Poly(acrylic acid)-Coated Alumina Particles

    SciTech Connect

    Bhosale, Prasad S.; Chun, Jaehun; Berg, John C.

    2011-06-01

    The effect of poly (acrylic acid) (PAA) adsorption on the electrokinetic behavior of alumina dispersions under high pH conditions was investigated as a function of polymer concentration and molecular weight as well as the presence, concentration and ion type of background electrolyte. Systems of this type are relevant to nuclear waste treatment, in which PAA is known to be an effective rheology modifier. The presence of all but the lowest molecular weight PAA studied (1800) led to decreases in dynamic electrophoretic mobility at low polymer concentrations, attributable to bridging flocculation, as verified by measurements of particle size distribution. Bridging effects increased with polymer molecular weight, and decreased with polymer concentration. Increases in background electrolyte concentration enhanced dynamic electrophoretic mobility as the polymer layers were compressed and bridging was reduced. Such enhancements were reduced as the cation was changed from Na+ to K+ to Cs+.

  16. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid... for use in contact with food subject to the provisions of this section. (a) The ethylene-acrylic...

  17. Dually cross-linked single network poly(acrylic acid) hydrogels with superior mechanical properties and water absorbency.

    PubMed

    Zhong, Ming; Liu, Yi-Tao; Liu, Xiao-Ying; Shi, Fu-Kuan; Zhang, Li-Qin; Zhu, Mei-Fang; Xie, Xu-Ming

    2016-06-28

    Poly(acrylic acid) (PAA) hydrogels with superior mechanical properties, based on a single network structure with dual cross-linking, are prepared by one-pot free radical polymerization. The network structure of the PAA hydrogels is composed of dual cross-linking: a dynamic and reversible ionic cross-linking among the PAA chains enabled by Fe(3+) ions, and a sparse covalent cross-linking enabled by a covalent cross-linker (Bis). Under deformation, the covalently cross-linked PAA chains remain intact to maintain their original configuration, while the Fe(3+)-enabled ionic cross-linking among the PAA chains is broken to dissipate energy and then recombined. It is found that the mechanical properties of the PAA hydrogels are significantly influenced by the contents of covalent cross-linkers, Fe(3+) ions and water, which can be adjusted within a substantial range and thus broaden the applications of the hydrogels. Meanwhile, the PAA hydrogels have excellent recoverability based on the dynamic and reversible ionic cross-linking enabled by Fe(3+) ions. Moreover, the swelling capacity of the PAA hydrogels is as high as 1800 times in deionized water due to the synergistic effects of ionic and covalent cross-linkings. The combination of balanced mechanical properties, efficient recoverability, high swelling capacity and facile preparation provides a new method to obtain high-performance hydrogels. PMID:27230478

  18. Swelling characteristics of acrylic acid polyelectrolyte hydrogel in a dc electric field

    NASA Astrophysics Data System (ADS)

    Jabbari, Esmaiel; Tavakoli, Javad; Sarvestani, Alireza S.

    2007-10-01

    A novel application of environmentally sensitive polyelectrolytes is in the fabrication of BioMEMS devices as sensors and actuators. Poly(acrylic acid) (PAA) gels are anionic polyelectrolyte networks that exhibit volume expansion in aqueous physiological environments. When an electric field is applied to PAA polyelectrolyte gels, the fixed anionic polyelectrolyte charges and the requirement of electro-neutrality in the network generate an osmotic pressure, above that in the absence of the electric field, to expand the network. The objective of this research was to investigate the effect of an externally applied dc electric field on the volume expansion of the PAA polyelectrolyte gel in a simulated physiological solution of phosphate buffer saline (PBS). For swelling studies in the electric field, two platinum-coated plates, as electrodes, were wrapped in a polyethylene sheet to protect the plates from corrosion and placed vertically in a vessel filled with PBS. The plates were placed on a rail such that the distance between the two plates could be adjusted. The PAA gel was synthesized by free radical crosslinking of acrylic acid monomer with ethylene glycol dimethacrylate (EGDMA) crosslinker. Our results demonstrate that volume expansion depends on the intensity of the electric field, the PAA network density, network homogeneity, and the position of the gel in the field relative to positive/negative electrodes. Our model predictions for PAA volume expansion, based on the dilute electrolyte concentration in the gel network, is in excellent agreement with the experimental findings in the high-electric-field regime (250-300 Newton/Coulomb).

  19. Interactions between poly(acrylic acid) and sodium dodecyl sulfate: isothermal titration calorimetric and surfactant ion-selective electrode studies.

    PubMed

    Wang, C; Tam, K C

    2005-03-24

    Interaction between a monodispersed poly(acrylic acid) (PAA) (M(W) = 5670 g/mol, M(w)/M(n) = 1.02) with sodium dodecyl sulfate (SDS) was investigated using isothermal titration calorimetry (ITC), ion-selective electrode (ISE), and dynamic light scattering measurements. Contrary to previous studies, we report for the first time evidence of interaction between SDS and PAA when the degree of neutralization (alpha) of PAA is lower than 0.2. Hydrocarbon chains of SDS cooperatively bind to apolar segments of PAA driven by hydrophobic interaction. The interaction is both enthalpy and entropy favored (deltaH is negative but deltaS is positive). In 0.05 wt % PAA solution, the SDS concentration corresponding to the onset of binding (i.e., CAC) is approximately 2.4 mM and the saturation concentration (i.e., C(S)) is approximately 13.3 mM when alpha = 0. When PAA was neutralized and ionized, the binding was hindered by the enhanced electrostatic repulsion between negatively charged SDS and PAA chains and improved solubility of the polymer. With increasing alpha to 0.2, CAC increases to approximately 6.2 mM, C(S) drops to 8.6 mM, and the interaction is significantly weakened where the amount of bound SDS on PAA is reduced considerably. The values of CAC and C(S) derived from different techniques are in good agreement. The binding results in the formation of mixed micelles on apolar PAA coils, which then expands and dissociates into single PAA chains. The majority of unneutralized PAA molecules exist as single polymer chains stabilized by bound SDS micelles in solution after the saturation concentration.

  20. Synthesis of poly acrylic acid modified silver nanoparticles and their antimicrobial activities.

    PubMed

    Ni, Zhihui; Wang, Zhihua; Sun, Lei; Li, Binjie; Zhao, Yanbao

    2014-08-01

    Poly acrylic acid modified silver (Ag/PAA) nanoparticles (NPs) have been successfully synthesized in the aqueous solution by using tannic acid as a reductant. The structure, morphology and composition of Ag/PAA NPs were characterized by various techniques such as X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible absorption spectroscopy (UV-vis) and thermogravimetry analysis (TGA). The results show that PAA/Ag NPs have a quasi-ball shape with an average diameter of 10 nm and exhibit well crystalline, and the reaction conditions have some effect on products morphology and size distribution. In addition, the as-synthesized Ag/PAA NPs antimicrobial activities against Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) were evaluated by the methods of broth dilution, cup diffusion, optical density (OD600) and electron microscopy observation. The as-synthesized Ag/PAA NPs exhibit excellent antibacterial activity. The antimicrobial mechanism may be attributed to the damaging of bacterial cell membrane and causing leakage of cytoplasm. PMID:24907758

  1. Behavior of Surface-Anchored Poly(acrylic acid) Brushes with Grafting Density Gradients on Solid Substrates: 1. Experiment

    SciTech Connect

    Wu,T.; Gong, P.; Szleifer, I.; Vicek, P.; Subr, V.; Genzer, J.

    2007-01-01

    We describe experiments pertaining to the formation of surface-anchored poly(acrylic acid) (PAA) brushes with a gradual variation of the PAA grafting densities on flat surfaces and provide detailed analysis of their properties. The PAA brush gradients are generated by first covering the substrate with a molecular gradient of the polymerization initiator, followed by the 'grafting from' polymerization of tert-butyl acrylate (tBA) from these substrate-bound initiator centers, and finally converting the PtBA into PAA. We use spectroscopic ellipsometry to measure the wet thickness of the grafted PAA chains in aqueous solutions at three different pH values (4, 5.8, and 10) and a series of ionic strengths (IS). Our measurements reveal that at low grafting densities, s, the wet thickness of the PAA brush (H) remains relatively constant, the polymers are in the mushroom regime. Beyond a certain value of s, the macromolecules enter the brush regime, where H increases with increasing s. For a given s, H exhibits a nonmonotonic behavior as a function of the IS. At large IS, the H is small because the charges along PAA are completely screened by the excess of the external salt. As IS decreases, the PAA enters the so-called salt brush (SB) regime, where H increases. At a certain value of IS, H reaches a maximum and then decreases again. The latter is a typical brush behavior in so-called osmotic brush (OB) regime. We provide detailed discussion of the behavior of the grafted PAA chains in the SB and OB regimes.

  2. Decolourization performance in C. I. Vat Yellow 1 aqueous suspension using hydrophobically modified poly(acrylic acid).

    PubMed

    Chen, J; Chen, M C

    2011-01-01

    A series of hydrophobically modified poly(acrylic acid) (PAA), poly(2-phenoxyethyl acrylate-co-acrylic acid) (poly(PHEA-co-AA)), have been synthesized and characterized by Ubbelohde type viscometry, Nuclear Magnetic Resonance (1H NMR) spectrometry and Differential Scanning Calorimetry (DSC). The shear thinning Non-Newtonian fluid behavior of their aqueous solution and the dependence on pH and hydrophobic group contents were found through apparent viscosity and rheological property investigating. Decolourization performance in C. I. Vat Yellow 1 aqueous suspension was evaluated through visible absorbance data. Decolourization performance of hydrophobically associated polymer indicates two times better than that of PAA. The quantitative relationship was mainly studied. PMID:21866762

  3. Electrospun Poly(acrylic acid)/Silica Hydrogel Nanofibers Scaffold for Highly Efficient Adsorption of Lanthanide Ions and Its Photoluminescence Performance.

    PubMed

    Wang, Min; Li, Xiong; Hua, Weikang; Shen, Lingdi; Yu, Xufeng; Wang, Xuefen

    2016-09-14

    Combined with the features of electrospun nanofibers and the nature of hydrogel, a novel choreographed poly(acrylic acid)-silica hydrogel nanofibers (PAA-S HNFs) scaffold with excellent rare earth elements (REEs) recovery performance was fabricated by a facile route consisting of colloid-electrospinning of PAA/SiO2 precursor solution, moderate thermal cross-linking of PAA-S nanofiber matrix, and full swelling in water. The resultant PAA-S HNFs with a loose and spongy porous network structure exhibited a remarkable adsorption capacity of lanthanide ions (Ln(3+)) triggered by the penetration of Ln(3+) from the nanofiber surface to interior through the abundant water channels, which took full advantage of the internal adsorption sites of nanofibers. The effects of initial solution pH, concentration, and contact time on adsorption of Ln(3+) have been investigated comprehensively. The maximum equilibrium adsorption capacities for La(3+), Eu(3+), and Tb(3+) were 232.6, 268.8, and 250.0 mg/g, respectively, at pH 6, and the adsorption data were well-fitted to the Langmuir isotherm and pseudo-second-order models. The resultant PAA-S HNFs scaffolds could be regenerated successfully. Furthermore, the proposed adsorption mechanism of Ln(3+) on PAA-S HNFs scaffolds was the formation of bidentate carboxylates between carboxyl groups and Ln(3+) confirmed by FT-IR and XPS analysis. The well-designed PAA-S HNFs scaffold can be used as a promising alternative for effective REEs recovery. Moreover, benefiting from the unique features of Ln(3+), the Ln-PAA-S HNFs simultaneously exhibited versatile advantages including good photoluminescent performance, tunable emission color, and excellent flexibility and processability, which also hold great potential for applications in luminescent patterning, underwater fluorescent devices, sensors, and biomaterials, among others. PMID:27537710

  4. Calcium Phosphate Mineralization in Cellulose Derivative/Poly(acrylic acid) Composites Having a Chiral Nematic Mesomorphic Structure.

    PubMed

    Ogiwara, Takuya; Katsumura, Ayaka; Sugimura, Kazuki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2015-12-14

    Calcium phosphate mineralization was conducted by using polymer composites of liquid-crystalline (ethyl)cellulose (EC) or (hydroxypropyl)cellulose (HPC) with poly(acrylic acid) (PAA) as a scaffolding medium for the inorganic deposition. The EC/PAA and HPC/PAA samples were prepared in colored film form from EC and HPC lyotropic liquid crystals of left-handed and right-handed chiral nematics, respectively, by polymerization and cross-linking of acrylic acid as the main solvent component. The mineralization was allowed to proceed in a batchwise operation by soaking the liquid-crystalline films in an aqueous salt solution containing the relevant ions, Ca(2+) and HPO4(2-). The calcium phosphate-deposited EC/PAA and HPC/PAA composites (weight gain, typically 15-25% and 6-11%, respectively) retained the chiral nematic organization of the respective original handedness but exhibited selective light-reflection of longer wavelengths relative to that of the corresponding nonmineralized samples. From X-ray diffraction and energy-dispersive X-ray spectroscopy measurements, it was deduced that the calcium and phosphorus were incorporated inside the polymer matrices in three forms: amorphous calcium phosphate, hydroxyapatite, and a certain complex of PAA-Ca(2+). Dynamic mechanical analysis and thermogravimetry revealed that the inorganic hybridization remarkably enhanced the thermal and mechanical performance of the optically functionalized cellulosic/synthetic polymer composites; however, the effect was more drastic in the EC/PAA series rather than the HPC/PAA series, reflecting the difference in the deposited mineral amount between the two. PMID:26536381

  5. 21 CFR 573.120 - Acrylamide-acrylic acid resin.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Acrylamide-acrylic acid resin. 573.120 Section 573.120 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED... Food Additive Listing § 573.120 Acrylamide-acrylic acid resin. Acrylamide-acrylic acid...

  6. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylamide-acrylic acid resins. 176.110 Section 176... Substances for Use Only as Components of Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components of articles intended for use in...

  7. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acrylamide-acrylic acid resins. 176.110 Section... Substances for Use Only as Components of Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components of articles intended for use in...

  8. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  9. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  10. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylamide-acrylic acid resins. 176.110 Section... Substances for Use Only as Components of Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components of articles intended for use in...

  11. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  12. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid copolymers identified in paragraph (a) of this section may be...

  13. 21 CFR 176.110 - Acrylamide-acrylic acid resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylamide-acrylic acid resins. 176.110 Section... Substances for Use Only as Components of Paper and Paperboard § 176.110 Acrylamide-acrylic acid resins. Acrylamide-acrylic acid resins may be safely used as components of articles intended for use in...

  14. ABS polymer electroless plating through a one-step poly(acrylic acid) covalent grafting.

    PubMed

    Garcia, Alexandre; Berthelot, Thomas; Viel, Pascal; Mesnage, Alice; Jégou, Pascale; Nekelson, Fabien; Roussel, Sébastien; Palacin, Serge

    2010-04-01

    A new, efficient, palladium- and chromium-free process for the electroless plating of acrylonitrile-butadiene-styrene (ABS) polymers has been developed. The process is based on the ion-exchange properties of poly(acrylic acid) (PAA) chemically grafted onto ABS via a simple and one-step method that prevents using classical surface conditioning. Hence, ABS electroless plating can be obtained in three steps, namely: (i) the grafting of PAA onto ABS, (ii) the copper Cu(0) seeding of the ABS surface, and (iii) the nickel or copper metallization using commercial-like electroless plating bath. IR, XPS, and SEM were used to characterize each step of the process, and the Cu loading was quantified by atomic absorption spectroscopy. This process successfully compares with the commercial one based on chromic acid etching and palladium-based seed layer, because the final metallic layer showed excellent adhesion with the ABS substrate. PMID:20361751

  15. Structure and Proton Conductivity in Mixtures of Poly(acrylic acid) and Imidazole

    NASA Astrophysics Data System (ADS)

    Yang, Han-Chang; Griffin, Philip J.; Winey, Karen I.; University of Pennsylvania Team

    2015-03-01

    Proton conductivity in polymer electrolyte membranes (PEMs) typically involves water, which requires that during operation the humidity of the PEM be carefully controlled. In contrast, anhydrous protic polymer membranes promote proton transport by incorporating heterocyclic molecules, such as imidazole and its derivatives, into acid-containing polymers. In this work, we explore the interplay between nanoscale-structure and proton conduction of poly(acrylic acid) (PAA) blended at varying compositions with 2-ethyl-4-methylimidazole (EMI). We present the glass transition temperature from differential scanning calorimetry, morphology characterization from X-ray scattering, and proton conductivity from electrical impedance spectroscopy.

  16. Surface grafted chitosan gels. Part I. Molecular insight into the formation of chitosan and poly(acrylic acid) multilayers.

    PubMed

    Liu, Chao; Thormann, Esben; Claesson, Per M; Tyrode, Eric

    2014-07-29

    Composite polyelectrolyte multilayers of chitosan and low molecular weight poly(acrylic acid) (PAA) have been assembled by sequential adsorption as a first step toward building a surface anchored chitosan gel. Silane chemistry was used to graft the first chitosan layer to prevent film detachment and decomposition. The assembly process is characterized by nonlinear growth behavior, with different adsorption kinetics for chitosan and PAA. In situ analysis of the multilayer by means of surface sensitive total internal reflection Raman (TIRR) spectroscopy, combined with target factor analysis of the spectra, provided information regarding composition, including water content, and ionization state of weak acidic and basic groups present in the thin composite film. Low molecular weight PAA, mainly in its protonated form, diffuses into and out of the composite film during adsorption and rinsing steps. The higher molecular weight chitosan shows a similar behavior, although to a much lower extent. Our data demonstrate that the charged monomeric units of chitosan are mainly compensated by carboxylate ions from PAA. Furthermore, the morphology and mechanical properties of the multilayers were investigated in situ using atomic force microscopy operating in PeakForce tapping mode. The multilayer consists of islands that grow in lateral dimension and height during the build-up process, leading to close to exponentially increasing roughness with deposition number. Both diffusion in and out of at least one of the two components (PAA) and the island-like morphology contribute to the nonlinear growth of chitosan/PAA multilayers.

  17. Tuning hemoglobin-poly(acrylic acid) interactions by controlled chemical modification with triethylenetetramine.

    PubMed

    Thilakarathne, Vindya K; Briand, Victoria A; Kasi, Rajeswari M; Kumar, Challa V

    2012-10-25

    Protein-polymer interactions play a very important role in a number of applications, but details of these interactions are not fully understood. Chemical modification was introduced here to tune protein-polymer interactions in a systematic manner, where methemoglobin (Hb) and poly(acrylic acid) (PAA) served as a model system. Under similar conditions of pH and ionic strength, the influence of protein charge on Hb/PAA interaction was studied using chemically modified Hb by isothermal titration calorimetry (ITC). A small fraction of COOH groups of Hb were amidated with triethylenetetramine (TETA) or ammonium chloride to produce the corresponding charge ladders of Hb-TETA and Hb-ammonia derivatives, respectively. All the Hb/PAA complexes produced here are bioactive, entirely soluble in water, and indicated the retention of Hb structure to a significant extent. Binding of Hb to PAA was exothermic (ΔH < 0). The binding of Hb-TETA charge ladder to PAA indicated decrease of ΔH from -8 ± 0.2 to -89 ± 4 kcal/mol, at a rate of -3.8 kcal/mol per unit charge introduced via modification. The Hb-ammonia charge ladder, in contrast, showed a decrease of ΔH from -8 ± 0.2 to -17 ± 1.5 kcal/mol, at much slower rate of -1.0 kcal/mol per unit charge. Thus, the amine used for the modification played a strong role in tuning Hb/PAA interactions, even after correcting for the charge, synergistically. Charge clustering may be responsible for this synergy, and this interesting observation may be exploited to construct protein/polymer platforms for advanced biomacromolecular applications.

  18. Cascade enzymatic catalysis in poly(acrylic acid) brushes-nanospherical silica for glucose detection.

    PubMed

    Zhao, Yan; Wang, Ying; Zhang, Xiaobin; Kong, Rongmei; Xia, Lian; Qu, Fengli

    2016-08-01

    The ultrasensitive monitoring of glucose with a fast and accurate method is significant in potential therapeutics and optimizes protein biosynthesis. Incorporation of enzyme into matrix is considered as promising candidates for constructing highly sensitive glucose-responsive systems. In this study, three-dimensional poly(acrylic acid) brushes-nanospherical silica (PAA-nano silica) with high amplification capability and stability were used to covalently immobilize bienzymes for cascade enzymatic catalysis. The major advantages of PAA-nano silica-bienzyme co-incorporation is that the enzymes are proximity distribution, and such close confinement both minimized the diffusion of intermediates among the enzymes in the consecutive reaction and improve the utilization efficiency of enzymes, thereby enhancing the overall reaction efficiency and specificity. Thus, this present bienzymatic biosensor shows robust signal amplification and ultrasensitivity of glucose-responsive properties with a detection limit of 0.04μM. PMID:27216683

  19. Antimicrobial activity of poly(vinyl alcohol)-poly(acrylic acid) electrospun nanofibers.

    PubMed

    Santiago-Morales, Javier; Amariei, Georgiana; Letón, Pedro; Rosal, Roberto

    2016-10-01

    Electrospun nanofibers were prepared from blends of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA). The fibers were stabilized by heat curing at 140°C via anhydride and ketone formation and crosslinking esterification. The antimicrobial effect was assessed using strains of Escherichia coli and Staphylococcus aureus by tracking their capacity to form colonies and their metabolic impairment upon contact with PAA/PVA membranes. Membranes containing >35wt.% PAA displayed significant antibacterial activity, which was particularly high for the gram-positive S. aureus. All membranes were negatively charged, with surface ζ-potential in the (-34.5)-(-45.6)mV range, but the electrostatic interaction with the negatively charged cells was not the reason for the antimicrobial effect. Neither pH reduction nor the passing of non-crosslinked polymers to the solution affected microbial growth. The antibacterial activity was attributed to the chelation of the divalent cations stabilizing the outer cell membrane. The effect on gram-positive bacteria was attributed to the destabilization of the peptidoglycan layer. The sequestration of divalent cations was demonstrated with experiments in which calcium and a chelating agent were added to the cultures in contact with membranes. The damage to bacterial cells was tracked by measuring their surface charge and the evolution of intracellular calcium during the early stages after contact with PAA/PVA membranes. PMID:27318959

  20. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

    PubMed Central

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

  1. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries.

    PubMed

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA. PMID:26786315

  2. Poly (acrylic acid sodium) grafted carboxymethyl cellulose as a high performance polymer binder for silicon anode in lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Wei, Liangming; Chen, Changxin; Hou, Zhongyu; Wei, Hao

    2016-01-01

    The design of novel binder systems is required for the high capacity silicon (Si) anodes which usually undergo huge volume change during the charge/discharge cycling. Here, we introduce a poly (acrylic acid sodium)-grafted-carboxymethyl cellulose (NaPAA-g-CMC) copolymer as an excellent binder for Si anode in lithium ion batteries (LIBs). The NaPAA-g-CMC copolymer was prepared via a free radical graft polymerization method by using CMC and acrylic acid as precursors. Unlike the linear, one-dimensional binders, the NaPAA-g-CMC copolymer binder is expected to present multi-point interaction with Si surface, resulting in enhanced binding ability with Si particles as well as with the copper (Cu) current collectors, and building a stable solid electrolyte interface (SEI) layer on the Si surface. The NaPAA-g-CMC based Si anode shows much better cycle stability and higher coulombic efficiency than those made with the well-known linear polymeric binders such as CMC and NaPPA.

  3. Complex Formation Between Lysozyme and Stabilized Micelles with a Mixed Poly(ethylene oxide)/Poly(acrylic acid) Shell.

    PubMed

    Karayianni, Maria; Gancheva, Valeria; Pispas, Stergios; Petrov, Petar

    2016-03-10

    The electrostatic complexation between lysozyme and stabilized polymeric micelles (SPMs) with a poly(acrylic acid) (PAA) or a mixed poly(ethylene oxide)/poly(acrylic acid) (PEO/PAA) shell (SPMs with a mixed shell, SPMMS) and a temperature-responsive poly(propylene oxide) (PPO) core was investigated by means of dynamic, static, and electrophoretic light scattering. The SPMs and different types of SPMMS used resulted from the self-assembly of PAA-PPO-PAA triblock copolymer chains, or PAA-PPO-PAA and PEO-PPO-PEO triblock copolymer chain mixtures (with varying chain lengths and molar ratios) in aqueous solutions at pH 10 and the subsequent cross-linking of their PPO cores via loading and photo-cross-linking of pentaerythritol tetraacrylate (PETA). The solution behavior, structure and properties of the formed complexes at pH 7 and 0.01 M ionic strength, were studied as a function of the protein concentration in the solution (the concentration of the stabilized micelles was kept constant) or equivalently the ratio of the two components. The complexation process and properties of the complexes proved to be dependent on the protein concentration, while of particular interest was the effect of the structure of the shell of the SPMs on the stability/solubility of the complexes. Finally, the fluorescence and mid infrared spectroscopic investigation of the structure of the complexed protein showed that, although a small stretching of the protein molecules occurred in some cases, no protein denaturation takes place upon complexation. PMID:26881445

  4. Highly luminescent lead sulfide nanocrystals in organic solvents and water through ligand exchange with poly(acrylic acid).

    PubMed

    Lin, Wanjuan; Fritz, Karolina; Guerin, Gerald; Bardajee, Ghasem R; Hinds, Sean; Sukhovatkin, Vlad; Sargent, Edward H; Scholes, Gregory D; Winnik, Mitchell A

    2008-08-01

    Hydrophobic lead sulfide quantum dots (PbS/OA) synthesized in the presence of oleic acid were transferred from nonpolar organic solvents to polar solvents such as alcohols and water by a simple ligand exchange with poly(acrylic acid) (PAA). Ligand exchange took place rapidly at room temperature When a colloidal solution of PbS/OA in tetrahydrofuran (THF) was treated with excess PAA, the PbS/PAA nanocrystals that formed were insoluble in hexane and toluene but could be dissolved in methanol or water, where they formed colloidal solutions that were stable for months. Ligand exchange was accompanied by a small blue shift in the band-edge absorption, consistent with a small reduction in particle size. While there was a decrease in quantum yield associated with ligand exchange and transfer to polar solvents, as is commonly found for colloidal quantum dots, the quantum yields determined were impressively high: PbS/OA in toluene (82%) and in THF (58%); PbS/PAA in THF (42%) and in water (24%). The quantum yields for the PbS/PAA solutions decreased over time as the solutions were allowed to age in the presence of air.

  5. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    NASA Astrophysics Data System (ADS)

    Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat; Amin, Mohd. Cairul Iqbal Mohd

    2014-09-01

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

  6. Chemical crosslinking of acrylic acid to form biocompatible pH sensitive hydrogel reinforced with cellulose nanocrystals (CNC)

    SciTech Connect

    Lim, Lim Sze; Ahmad, Ishak; Lazim, Mohd Azwani Shah Mat; Amin, Mohd. Cairul Iqbal Mohd

    2014-09-03

    The purpose of this study is to produce a novel pH and temperature sensitive hydrogel, composed of poly(acrylic acid) (PAA) and cellulose nanocrystal (CNC). CNC was extracted from kenaf fiber through a series of alkali and bleaching treatments followed by acid hydrolysis. The PAA was then subjected to chemical cross-linking using the cross-linking agent (N,N-methylenebisacrylamide) with CNC entrapped in PAA matrix. The mixture was casted onto petri dish to obtain disc shape hydrogel. The effects of reaction conditions such as the ratio of PAA and CNC on the swelling behavior of the hydrogel obtained towards pH and temperature were studied. The obtained hydrogel was further subjected to different tests such swelling test for swelling behaviour at different pH and temperature along with scanning electron microscopy (SEM) for morphology analysis. The hydrogel obtained showed excellent pH sensitivity and obtained maximum swelling at pH 7. Besides that, hydrogel obtained showed significant increase in swelling ratio when temperature of swelling medium was increased from 25°C to 37°C. SEM micrograph showed that the pore size of the hydrogel decreases with increase of CNC content proving that the hydrogel structure became more rigid with addition of CNC. The PAA/CNC hydrogel with such excellent sensitivity towards pH and temperature can be developed further as drug carrier.

  7. Poly(acrylic acid)/polyethylene glycol hygrogel prepared by using gamma-ray irradiation for mucosa adhesion

    NASA Astrophysics Data System (ADS)

    Nho, Young-Chang; Park, Jong-Seok; Shin, Jung-Woong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Gwon, Hui-Jeong; Khil, Myung-Seob; Lee, Deok-Won; Ahn, Sung-Jun

    2015-01-01

    A buccal delivery system provides a much milder environment for drug delivery compared to an oral delivery which presents a hostile environment for drugs, especially proteins and polypeptides, owing to acid hydrolysis. Local delivery in an oral cavity has particular applications in the treatment of toothaches, periodontal disease, and bacterial infections. Poly(acrylic acid) (PAA)-based hydrogels prepared using a chemical initiator have been attempted for a mucoadhesive system owing to their flexibility and excellent bioadhesion. In this experiment, PAA and polyethylene glycol (PEG) were selected to prepare using a radiation process a bioadhesive hydrogel for adhesion to mucosal surfaces. PAA and PEG were dissolved in purified water to prepare a homogeneous PAA/PEG solution, and the solution was then irradiated using an electron beam at dose up to 70 kGy to make the hydrogels. Their physical properties, such as gel percent, swelling percent, and adhesive strength to mucosal surfaces, were investigated. In this experiment, various amounts of PEG were incorporated into the PAA to enhance the mucoadhesive property of the hydrogels. The effect of the molecular weight of PEG on the mucoadhesion was also examined.

  8. Effects of gas atmospheres on poly(lactic acid) film in acrylic acid plasma treatment

    NASA Astrophysics Data System (ADS)

    Zhao, Yun; Fina, Alberto; Venturello, Alberto; Geobaldo, Francesco

    2013-10-01

    Plasma polymerized acrylic acid (AA) coatings were deposited on poly(lactic acid) (PLA) films in various gas atmospheres during the pre-treatment of PLA and the deposition of AA, respectively. Therefore, this work was twofold: the argon pretreated PLA films followed by a deposition in argon were investigated against the mixture of argon and oxygen pretreated ones under the same deposition conditions; the plasma deposition of AA operating in different atmospheres (argon, oxygen and nitrogen) was employed to modify the pretreated PLA in oxygen. Chemical and physical changes on the plasma-treated surfaces were examined using contact angle, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and attenuated total reflection infrared (ATR-FTIR) analysis. The results showed that the discharge gas can have a significant influence on the chemical composition of the PLA surfaces: oxygen plasmas introduced oxygen-containing groups in company with surface etching in pretreatment and deposition, while argon discharges was able to achieve much better hydrophilic behavior and high retention ratio of poly(acrylic acid) (PAA) coating before and after washing in water.

  9. Structural tailoring of hydrogen-bonded poly(acrylic acid)/poly(ethylene oxide) multilayer thin films for reduced gas permeability.

    PubMed

    Xiang, Fangming; Ward, Sarah M; Givens, Tara M; Grunlan, Jaime C

    2015-02-01

    Hydrogen bonded poly(acrylic acid) (PAA)/poly(ethylene oxide) (PEO) layer-by-layer assemblies are highly elastomeric, but more permeable than ionically bonded thin films. In order to expand the use of hydrogen-bonded assemblies to applications that require a better gas barrier, the effect of assembling pH on the oxygen permeability of PAA/PEO multilayer thin films was investigated. Altering the assembling pH leads to significant changes in phase morphology and bonding. The amount of intermolecular hydrogen bonding between PAA and PEO is found to increase with increasing pH due to reduction of COOH dimers between PAA chains. This improved bonding leads to smaller PEO domains and lower gas permeability. Further increasing the pH beyond 2.75 results in higher oxygen permeability due to partial deprotonation of PAA. By setting the assembling pH at 2.75, the negative impacts of COOH dimer formation and PAA ionization on intermolecular hydrogen bonding can be minimized, leading to a 50% reduction in the oxygen permeability of the PAA/PEO thin film. A 20 bilayer coating reduces the oxygen transmission rate of a 1.58 mm natural rubber substrate by 20 ×. These unique nanocoatings provide the opportunity to impart a gas barrier to elastomeric substrates without altering their mechanical behavior.

  10. Properties and mechanisms of drug release from matrix tablets containing poly(ethylene oxide) and poly(acrylic acid) as release retardants.

    PubMed

    Zhang, Feng; Meng, Fan; Lubach, Joseph; Koleng, Joseph; Watson, N A

    2016-08-01

    The interactions between poly(ethylene oxide) (PEO) and poly(acrylic acid) (PAA) in aqueous medium at pH 6.8 were investigated in the current study. We have also studied the effect of interpolymer interactions and various formulation variables, including the molecular weight of PEO, the ratio between PEO and PAA, the crystallinity of PEO, and the presence of an acidifying agent, on the release of theophylline from matrix tablets containing both PEO and PAA as release retardants. At pH 6.8, the synergy in solution viscosity between PEO and PAA as the result of ion-dipole interaction was observed in this study. The release of theophylline from the matrix tablets containing physical mixtures of PEO and PAA was found to be a function of dissolution medium pH because of the pH-dependent interactions between these two polymers. Because of the formation of water insoluble interpolymer complex between PEO and PAA in aqueous medium at pH below 4.0, the release of theophylline was independent of PEO molecular weight and was controlled by Fickian diffusion mechanism in 0.01N hydrochloric acid solution. In comparison, the drug release was a function of PEO molecular weight and followed the anomalous transport mechanism in phosphate buffer pH 6.8. The presence of PAA exerted opposite effects on the release of theophylline in phosphate buffer pH 6.8. In one aspect, theophylline release was accelerated because the erosion of PAA was much faster than that of PEO at pH6.8. On the opposite aspect, theophylline release was slowed down because of the formation of insoluble complex inside the gel layer as the result of the acidic microenvironment induced by PAA, and the increase in the viscosity of the gel layer as the result of the synergy between PEO and PAA. These two opposite effects offset each other. As a result, the release of theophylline remained statistically the same even when 75% PEO in the formulation was replaced with PAA. In phosphate buffer pH 6.8, the release of

  11. Formation of acrylic acid from lactic acid in supercritical water

    SciTech Connect

    Mok, W.S.L.; Antal, M.J. Jr. ); Jones, M. Jr. )

    1989-09-15

    Supercritical (SC) water is an unusual medium in which fast and specific heterolytic reactions can be conducted at temperatures as high as 400{degree}C. In supercritical water, lactic acid decomposes into gaseous and liquid products via three primary reaction pathways. Products of the acid-catalyzed heterolytic decarbonylation pathway are carbon monoxide, water, and acetaldehyde. Products of the homolytic, decarboxylation pathway are carbon dioxide, hydrogen, and acetaldehyde. Products of the heterolytic, dehydration pathway are acrylic acid and water. The intramolecular nucleophilic displacement of the {alpha}-hydroxyl by the carbonyl group of lactic acid, producing {alpha}-propiolactone as an unstable intermediate which subsequently rearranges to become the unsaturated acid, is a likely mechanism for acrylic acid formation, although an intramolecular E2 elimination initiated by attack of the carbonyl oxygen on a methyl hydrogen cannot be ruled out. Support for the former mechanism comes in part from the observed 100% relative yield of acrylic acid from {beta}-propiolactone in SC water.

  12. Disinfection with peracetic acid (PAA), an alternative against fish pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because of the lack of approved substances to treat fish diseases, disinfecting substances are tested to treat fish pathogens. These agents should not leave dangerous residues in the environment in order to successfully contribute to sustainable aquaculture. One of these substances is peracetic acid...

  13. Fabrication and Characterization of Gd-DTPA-Loaded Chitosan-Poly(Acrylic Acid) Nanoparticles for Magnetic Resonance Imaging.

    PubMed

    Ahmed, Arsalan; Zhang, Chao; Guo, Jian; Hu, Yong; Jiang, Xiqun

    2015-08-01

    Gd-DTPA-loaded chitosan-poly(acrylic acid) nanoparticles (Gd-DTPA@CS-PAA NPs) were formulated based on the reaction system of water-soluble polymer-monomer pairs of acrylic acid in chitosan solution followed by sorption of Gd-DTPA. Morphological investigations revealed the spherical shape of these NPs with about 220 nm particle size. These NPs showed charge reversal characteristic in acidic solution. In vitro and in vivo magnetic characteristics of these NPs were explored to estimate their utilization in targeted enhanced magnetic resonance imaging. Relaxation studies showed that these NPs possessed pH susceptible relaxation properties, which could introduce in vivo-specific distribution of contrast agent. MRI experiment showed that these nanoparticles had better results in contrast enhancement, and the concentration of contrast agent increased in liver and brain with increment in time. Thus, these NPs could maintain in vivo long circulation and high relaxation rate and were suitable agents for magnetic resonance imaging.

  14. Investigation of Acrylic Acid at High Pressure Using Neutron Diffraction

    PubMed Central

    2014-01-01

    This article details the exploration of perdeuterated acrylic acid at high pressure using neutron diffraction. The structural changes that occur in acrylic acid-d4 are followed via diffraction and rationalized using the Pixel method. Acrylic acid undergoes a reconstructive phase transition to a new phase at ∼0.8 GPa and remains molecular to 7.2 GPa before polymerizing on decompression to ambient pressure. The resulting product is analyzed via Raman and FT-IR spectroscopy and differential scanning calorimetry and found to possess a different molecular structure compared with polymers produced via traditional routes. PMID:24650085

  15. Polyaniline/poly acid acrylic thin film composites: a new gamma radiation detector

    SciTech Connect

    Lima Pacheco, Ana P.; Araujo, Elmo S.; Azevedo, Walter M. de

    2003-03-15

    In this paper, we present a new and straightforward route to prepare polyaniline/poly acid acrylic (PAA) thin film composites in large areas and on almost any surface. This method was developed to improve the mechanical and adherence properties of polyaniline devices used as ionization radiation sensors. The route consists of the combination of the metal oxidant with polymer acid to form a highly homogeneous and viscous paste, which can be easily spread over any surface. In the second step, an aniline acid solution is brought in contact with the dried paste where polymerization occurs, yielding a high homogeneous and conducting polymer composite. The UV-visible absorption and infrared analysis confirm that a polyaniline/PAA complex is obtained. The four-point conductivity measurements show that the composite conductivity {rho} is the order of 5 {omega}{sup -1} cm{sup -1}. Preliminary gamma radiation interaction with the composite shows that the doped composite exhibits a linear response that can be used in the development of real-time radiation sensors for the dose range from 0 to 5000 Gy.

  16. Semi-crystalline polymethylene-b-poly(acrylic acid) diblock copolymers: aggregation behavior, confined crystallization and controlled growth of semicrystalline micelles from dilute DMF solution.

    PubMed

    Wang, Hongfang; Wu, Cong; Xia, Guangmei; Ma, Zhi; Mo, Guang; Song, Rui

    2015-03-01

    In this paper, we have systematically investigated the aggregation behavior, confined crystallization and controlled growth of a novel polyolefin analogue-containing block copolymers (BCPs), i.e., polymethylene-b-poly(acrylic acid) diblock copolymers (PM-b-PAA). On cooling from a homogenous DMF solution at 80 °C, PM-b-PAA was found to crystallize and aggregate with well-defined disk-like micelles. The aggregate behavior and in-plane morphology of PM-b-PAA could be easily controlled by modifying the block ratio, solution pH and solvent composition (DMF-water), by manipulating the crystallization of PM block and the stretching degree of solvated PAA corona. Further investigation of the crystalline feature of PM-b-PAA indicated that the crystallization of PM was retarded by tethered amorphous PAA segments. The crystalline micelle could construct a nano-confined environment with PM folding as the core into a thickness of the mono-layered polyethylene. Finally, when cultured in dilute DMF solution at 50 °C, the initial crystalline micelles, being as self-seeds, could follow a living growth mechanism and develop into single crystals, with well-defined lozenge-shaped morphology.

  17. Semi-crystalline polymethylene-b-poly(acrylic acid) diblock copolymers: aggregation behavior, confined crystallization and controlled growth of semicrystalline micelles from dilute DMF solution.

    PubMed

    Wang, Hongfang; Wu, Cong; Xia, Guangmei; Ma, Zhi; Mo, Guang; Song, Rui

    2015-03-01

    In this paper, we have systematically investigated the aggregation behavior, confined crystallization and controlled growth of a novel polyolefin analogue-containing block copolymers (BCPs), i.e., polymethylene-b-poly(acrylic acid) diblock copolymers (PM-b-PAA). On cooling from a homogenous DMF solution at 80 °C, PM-b-PAA was found to crystallize and aggregate with well-defined disk-like micelles. The aggregate behavior and in-plane morphology of PM-b-PAA could be easily controlled by modifying the block ratio, solution pH and solvent composition (DMF-water), by manipulating the crystallization of PM block and the stretching degree of solvated PAA corona. Further investigation of the crystalline feature of PM-b-PAA indicated that the crystallization of PM was retarded by tethered amorphous PAA segments. The crystalline micelle could construct a nano-confined environment with PM folding as the core into a thickness of the mono-layered polyethylene. Finally, when cultured in dilute DMF solution at 50 °C, the initial crystalline micelles, being as self-seeds, could follow a living growth mechanism and develop into single crystals, with well-defined lozenge-shaped morphology. PMID:25608942

  18. UV-induced graft polymerization of acrylic acid in the sub-micronchannels of oxidized PET track-etched membrane

    NASA Astrophysics Data System (ADS)

    Korolkov, Ilya V.; Mashentseva, Anastassiya A.; Güven, Olgun; Taltenov, Abzal A.

    2015-12-01

    In this article, we report on functionalization of track-etched membrane based on poly(ethylene terephthalate) (PET TeMs) oxidized by advanced oxidation systems and by grafting of acrylic acid using photochemical initiation technique for the purpose of increasing functionality thus expanding its practical application. Among advanced oxidation processes (H2O2/UV) system had been chosen to introduce maximum concentration of carboxylic acid groups. Benzophenone (BP) photo-initiator was first immobilized on the surfaces of cylindrical pores which were later filled with aq. acrylic acid solution. UV-irradiation from both sides of PET TeMs has led to the formation of grafted poly(acrylic acid) (PAA) chains inside the membrane sub-micronchannels. Effect of oxygen-rich surface of PET TeMs on BP adsorption and subsequent process of photo-induced graft polymerization of acrylic acid (AA) were studied by ESR. The surface of oxidized and AA grafted PET TeMs was characterized by UV-vis, ATR-FTIR, XPS spectroscopies and by SEM.

  19. A Novel Route for Preparing Highly Stable Fe3O4 Fluid with Poly(Acrylic Acid) as Phase Transfer Ligand

    NASA Astrophysics Data System (ADS)

    Oanh, Vuong Thi Kim; Lam, Tran Dai; Thu, Vu Thi; Lu, Le Trong; Nam, Pham Hong; Tam, Le The; Manh, Do Hung; Phuc, Nguyen Xuan

    2016-08-01

    Highly stable Fe3O4 liquid was synthesized by thermal decomposition using poly(acrylic acid) (PAA) as a phase transfer ligand. The crystalline structure, morphology, and magnetic properties of the as-prepared samples were thoroughly characterized. Results demonstrated that the magnetic Fe3O4 nanomaterial was formed in liquid phase with a spinel single-phase structure, average size of 8-13 nm, and high saturation magnetization (up to 75 emu/g). The PAA-capped Fe3O4 nanoparticles displayed high stability over a wide pH range (from 4 to 7) in 300 mM salt solution. More importantly, the heat-generating capacity of the nanoparticle systems was quantified at a specific absorption rate (SAR) of 70.22 W/g, which is 35% higher than magnetic nanoparticles coated with sodium dodecyl sulfate (SDS). These findings suggest the potential application of PAA-coated magnetic nanoparticles in magnetic hyperthermia.

  20. Water dispersible polytetrafluoroethylene microparticles prepared by grafting of poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Yang, Changqiao; Xu, Lu; Zeng, Hongyan; Tang, Zhongfeng; Zhong, Lei; Wu, Guozhong

    2014-10-01

    Due to the hydrophobic nature and high gravimetric density, it is very difficult to obtain water dispersible polytetrafluoroethylene (PTFE) powder. In this work, hydrophilic PTFE microparticles were successfully prepared by grafting of poly(acrylic acid) onto PTFE micropowder via a pre-irradiation method. The as-obtained hydrophilic PTFE microparticles were analyzed by FT-IR, 1H NMR, CA, SEM and TGA. After neutralization by sodium hydroxide, the water contact angle decreased from 145.69° for pristine PTFE to 63.38° for PTFE-g-NaAA. The obtained micropowder can be easily dispersed in water to form a dispersion with very high stability. Furthermore, the presence of grafted PAA shows no obvious influence on degradation temperature of PTFE backbones.

  1. Photopolymerisation and characterization of maleylatedcellulose-g-poly(acrylic acid) superabsorbent polymer.

    PubMed

    Sawut, Amatjan; Yimit, Mamatjan; Sun, Wanfu; Nurulla, Ismayil

    2014-01-30

    A novel biodegradable superabsorbent polymer has been prepared from maleylated cotton stalk cellulose (MCSC) crosslinker and acrylic acid (AA) by ultraviolet (UV) photopolymerization in aqueous solution at room temperature, and irgacure 651 as a photoinitiator. The resulting superabsorbent was characterized by FT-IR, (1)H NMR, SEM and TGA. The effects of preparation conditions such as degree of substitution (DS), amount of maleylated cotton stalk cellulose, exposed time, photoinitiator amount and monomer concentration on the water absorbency and the monomer conversion in graft were evaluated. The swelling kinetics, salt-resistance, water retention capacity and biodegradability of the MCSC-g-PAA superabsorbent were investigated. It was found that, the obtained superabsorbent have good swelling degree that greatly affected by its composition and preparation conditions. Owing to its considerable good water retention capacity, being economical and environment-friendly, it might be useful for its application in agriculture field.

  2. Photopolymerisation and characterization of maleylatedcellulose-g-poly(acrylic acid) superabsorbent polymer.

    PubMed

    Sawut, Amatjan; Yimit, Mamatjan; Sun, Wanfu; Nurulla, Ismayil

    2014-01-30

    A novel biodegradable superabsorbent polymer has been prepared from maleylated cotton stalk cellulose (MCSC) crosslinker and acrylic acid (AA) by ultraviolet (UV) photopolymerization in aqueous solution at room temperature, and irgacure 651 as a photoinitiator. The resulting superabsorbent was characterized by FT-IR, (1)H NMR, SEM and TGA. The effects of preparation conditions such as degree of substitution (DS), amount of maleylated cotton stalk cellulose, exposed time, photoinitiator amount and monomer concentration on the water absorbency and the monomer conversion in graft were evaluated. The swelling kinetics, salt-resistance, water retention capacity and biodegradability of the MCSC-g-PAA superabsorbent were investigated. It was found that, the obtained superabsorbent have good swelling degree that greatly affected by its composition and preparation conditions. Owing to its considerable good water retention capacity, being economical and environment-friendly, it might be useful for its application in agriculture field. PMID:24299769

  3. Accelerated Amidization of Branched Poly(ethylenimine)/Poly(acrylic acid) Multilayer Films by Microwave Heating.

    PubMed

    Lin, Kehua; Gu, Yuanqing; Zhang, Huan; Qiang, Zhe; Vogt, Bryan D; Zacharia, Nicole S

    2016-09-13

    Chemical cross-linking of layer-by-layer assembled films promotes mechanical stability and robustness in a wide variety of environments, which can be a challenge for polyelectrolyte multilayers in saline environments or for multilayers made from weak polyelectrolytes in environments with extreme pHs. Heating branched poly(ethylenimine)/poly(acrylic acid) (BPEI/PAA) multilayers at sufficiently high temperatures drives amidization and dehydration to covalently cross-link the film, but this reaction is rather slow, typically requiring heating for hours for appreciable cross-linking to occur. Here, a more than one order of magnitude increase in the amidization kinetics is realized through microwave heating of BPEI/PAA multilayers on indium tin oxide (ITO)/glass substrates. The cross-linking reaction is tracked using infrared spectroscopic ellipsometry to monitor the development of the cross-linking products. For thick films (∼1500 nm), gradients in cross-link density can be readily identified by infrared ellipsometry. Such gradients in cross-link density are driven by the temperature gradient developed by the localized heating of ITO by microwaves. This significant acceleration of reactions using microwaves to generate a well-defined cross-link network as well as being a simple method for developing graded materials should open new applications for these polymer films and coatings. PMID:27548626

  4. Preparation and properties of poly(acrylic acid) oligomer stabilized superparamagnetic ferrofluid.

    PubMed

    Lin, Chia-Lung; Lee, Chia-Fen; Chiu, Wen-Yen

    2005-11-15

    Ferrofluids, which are stable dispersions of magnetic particles, behave as liquids that have strong magnetic properties. Nanoparticles of magnetite with a mean diameter of 10-15 nm, which are in the range of superparamagnetism, are usually prepared by the traditional method of co-precipitation from ferrous and ferric electrolyte solution. When diluted, the ferrofluid dispersions are not stable if anionic or cationic surfactants are used as the stabilizer. This work presents an efficient way to prepare a stable aqueous nanomagnetite dispersion. A stable ferrofluid containing Fe3O4 nanoparticles was synthesized via co-precipitation in the presence of poly(acrylic acid) oligomer. The mechanism, microstructure, and properties of the ferrofluid were investigated. The results indicate that the PAA oligomers promoted the nucleation and inhibited the growth of the magnetic iron oxide, and the average diameter of each individual Fe3O4 particle was smaller than 10 nm. In addition, the PAA oligomers provided both electrostatic and steric repulsion against particle aggregation, and the stability of dispersions could be controlled by adjusting the pH value of solution. A small amount of Fe2O3 was found in the nanoparticles but the superparamagnetic behavior of the nanoparticles was not affected. PMID:16009367

  5. Nanoclays reinforced glass ionomer cements: dispersion and interaction of polymer grade (PG) montmorillonite with poly(acrylic acid).

    PubMed

    Fareed, Muhammad A; Stamboulis, Artemis

    2014-01-01

    Montmorillonite nanoclays (PGV and PGN) were dispersed in poly(acrylic acid) (PAA) for utilization as reinforcing filler in glass ionomer cements (GICs). Chemical and physical interaction of PAA and nanoclay (PGV and PGN) was studied. PAA–PGV and PAA–PGN solutions were prepared in different weight percent loadings of PGV and PGN nanoclay (0.5-8.0 wt%) via exfoliation-adsorption method. Characterization was carried out by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and fourier transform infrared (FTIR) spectroscopy. XRD results of PAA–PGN demonstrated that the interlayer space expanded from 12.83 to 16.03 Å indicating intercalation whereas the absence of the peak at d(001) in PAA–PGV indicated exfoliation. XPS scans of PGV and PGN nanoclays depicted the main peak of O 1s photoelectron due to Si–O–M (M = Mg, Al, Fe) whereas, Si–O–Al linkages were identified by Si 2p or Si 2s and Al 2p or Al 2s peaks. The disappearance of the Na peak confirmed that PAA molecules exchanged sodium ions present on surface of silicate layers and significantly reduced the electrostatic van-der-Waals forces between silicate plates resulting in intercalation or exfoliation. FTIR spectra of PAA–nanoclay suspensions demonstrated the presence of a new peak at 1,019 cm(-1) associated with Si–O– stretching vibrations which increased with increasing nanoclays concentration. Information concerning the dispersion of nanoclay in PAA aqueous solutions, chemical reaction and increase interlayer space in montmorillonite nanoclay is particularly useful regarding dispersion and reinforcement of nanoclay in PAA. PMID:24077996

  6. Rheology and adhesion of poly(acrylic acid)/laponite nanocomposite hydrogels as biocompatible adhesives.

    PubMed

    Shen, Muxian; Li, Li; Sun, Yimin; Xu, Jun; Guo, Xuhong; Prud'homme, Robert K

    2014-02-18

    Biocompatible nanocomposite hydrogels (NC gels) consisting of poly(acrylic acid) (PAA) and nanosized clay (Laponite) were successfully synthesized by in situ free-radical polymerization of acrylic acid (AA) in aqueous solutions of Laponite. The obtained NC gels were uniform and transparent. Their viscosity, storage modulus G', and loss modulus G″ increased significantly upon increasing the content of Laponite and the dose of AA, while exhibiting a maximum with increasing the neutralization degree of AA. They showed tunable adhesion by changing the dose of Laponite and monomer as well as the neutralization degree of AA, as determined by 180° peel strength measurement. The maximal adhesion was shown when reaching a balance between cohesion and fluidity. A homemade Johnson-Kendall-Roberts (JKR) instrument was employed to study the surface adhesion behavior of the NC gels. The combination of peel strength, rheology, and JKR measurements offers the opportunity of insight into the mechanism of adhesion of hydrogels. The NC gels with tunable adhesion should be ideal candidates for dental adhesive, wound dressing, and tissue engineering. PMID:24460239

  7. PAA/PEO comb polymer effects on the rheological property evolution in concentrated cement suspensions

    NASA Astrophysics Data System (ADS)

    Kirby, Glen Harold

    We have studied the behavior of polyelectrolyte-based comb polymers in dilute solution and on the rheological property evolution of concentrated Portland cement suspensions. These species consisted of charge-neutral, poly(ethylene oxide) (PEO) "teeth" grafted onto a poly(acrylic acid) (PAA) "backbone" that contains one ionizable carboxylic acid group (COOH) per monomer unit. As a benchmark, our observations were compared to those obtained for pure cement pastes and systems containing pure polyelectrolyte species, i.e., sulfonated naphthalene formaldehyde (SNF) and poly(acrylic acid) (PAA). The behavior of PAA/PEO comb polymers, SNF, and PAA in dilute solution was studied as a function of pH in the absence and presence of mono-, di-, and trivalent counterions. Light scattering and turbidity measurements were carried out to assess their hydrodynamic radius and stability in aqueous solution, respectively. PAA experienced large conformational changes as a function of solution pH and ionic strength. Moreover, dilute solutions of ionized SNF and PAA species became unstable in the presence of multivalent counterions due to ion-bridging interactions. PAA/PEO solutions exhibited enhanced stability relative to pure polyelectrolytes under analogous conditions. The charge neutral PEO teeth shielded the underlying PAA backbone from ion-bridging interactions. In addition, such species hindered conformational changes in solution due to steric interactions between adjacent teeth. A new oscillatory shear technique was developed to probe the rheological property evolution of concentrated cement systems. The rheological property evolution of ordinary and white Portland cement systems were studied in the absence and presence of pure polyelectrolytes and PAA/PEO comb polymers with a wide range of PAA backbone molecular weight, PEO teeth molecular weight, and acid:imide ratio. Cement-PAA suspensions experienced rapid irreversible stiffening and set at 6 min due to ion

  8. Aggregation of poly(acrylic acid)-containing elastin-mimetic copolymers

    PubMed Central

    Paik, Bradford A.; Blanco, Marco A.; Jia, Xinqiao; Roberts, Christopher J.; Kiick, Kristi L.

    2015-01-01

    Polymer-peptide conjugates were produced via the copper-catalyzed alkyne-azide cycloaddition of poly(tert butyl acrylate) (PtBA) and elastin-like peptides. An azide-functionalized polymer was produced via atom-transfer radical polymerization (ATRP) followed by conversion of bromine end groups to azide groups. Subsequent reaction of the polymer with a bis-alkyne-functionalized, elastin-like peptide proceeded with high efficiency, yielding di- and tri-block conjugates, which after deprotection, yielded poly(acrylic acid) (PAA)-based diblock and triblock copolymers. These conjugates were solubilized in dimethyl formamide, and titration of phosphate buffered saline (PBS) induced aggregation. The presence of polydisperse spherical aggregates was confirmed by dynamic light scattering and transmission electron microscopy. Additionally, a coarse-grained molecular model was designed to reasonably capture inter- and intramolecular interactions for the conjugates and its precursors. This model was used to assess the effect of the different interacting molecular forces on the conformational thermodynamic stability of the copolymers. Our results indicated that the PAA’s ability to hydrogen-bond with both itself and the peptide is the main interaction for stabilizing the diblocks and triblocks and driving their self-assembly, while interactions between peptides are suggested to play only a minor role on the conformational and thermodynamic stability of the conjugates. PMID:25611563

  9. Salinity, water hardness, and dissolved organic carbon modulate degradation of peracetic acid (PAA) compounds in aqueous solutions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is used in aquaculture under different conditions for disinfection purposes. However, there is a lack of information about its environmental fate, particularly its persistence in aquatic systems with different chemistries. Therefore, the impact of water hardness, salinity, and d...

  10. Rheology and interfacial properties of aqueous solutions of the diblock polyelectrolyte poly(styrene-block-acrylic acid)

    NASA Astrophysics Data System (ADS)

    Kimerling, Abigail

    In aqueous solutions diblock polyelectrolytes with amphiphilic character form aggregate structures, which affect physical properties such as viscosity, elasticity, surface tension, and film hydrophilicity. Potential applications for diblock polyelectrolyte solutions include coatings, inks, oil recovery agents, personal care products, and biomaterials. By varying the diblock polyelectrolyte and solution properties, the solutions can be tuned to meet the needs of particular applications. The research objective was to identify the influences of block length, pH, and ionic strength on the rheological and interfacial properties of poly(styrene- b-acrylic acid) (PS-PAA) solutions. Six polymers with varied PS and PAA block lengths were examined, all at 1.0 wt% in aqueous solutions. The hydrophobicity of the PS block causes the formation of spherical micelles in aqueous solutions. Increasing the solution pH ionizes the PAA block, which leads to an increase in micelle corona thickness due to repulsions between chains. Major trends observed in the rheological and interfacial properties can be understood in terms of expected changes in the micelle size and interfacial self-assembly with pH, ionic strength, and block length. Addition of NaOH was found to increase the solution pH and initially led to increases in solution viscosity, elasticity, surface tension, and film hydrophilicity. This effect was attributed to creation of larger micelles and greater inter-micellar repulsions as the PAA chain became more fully charged. However, when the concentration of NaOH exceeded a critical value, the solution viscosity, elasticity, and film hydrophilicity decreased. It is believed this was due to charge shielding by excess sodium ions, leading to shrinkage of the micelle corona and smaller micelles. Increasing the PS-PAA solution ionic strength by adding NaCl also provided charge shielding, as observed by decreases in solution viscosity and elasticity. Increasing the length of either

  11. Preparation of mesoporous poly (acrylic acid)/SiO2 composite nanofiber membranes having adsorption capacity for indigo carmine dye

    NASA Astrophysics Data System (ADS)

    Xu, Ran; Jia, Min; Li, Fengting; Wang, Hongtao; Zhang, Bingru; Qiao, Junlian

    2012-03-01

    Mesoporous poly (acrylic acid)/SiO2 (PAA/SiO2) composite nanofiber membranes functionalized with mercapto groups were fabricated by a sol-gel electrospinning method, and their adsorption capacity for indigo carmine was investigated. The membranes were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, x-ray powder diffraction (XRD), and nitrogen adsorption-desorption measurement. SEM and TEM observation results showed that the PAA/SiO2 fibers had diameters between 400-800 nm and mesopores with an average pore size of 3.88 nm. The specific surface area of the mesoporous nanofiber membranes was 514.89 m2/g. The characteristic peaks for mercapto group vibration in FTIR and Raman spectra demonstrated that the mercapto groups have been incorporated into the silica skeleton. The adsorption isotherm data of indigo carmine on the membranes fit well with Redlich-Peterson model, and the maximum adsorption capacity calculated was 523.11 mg/g. It was found that the removal rate of indigo carmine by the membranes reached a maximum of 98% in 90 min and the adsorption kinetics followed a pseudo-second-order model. The high adsorption capacity of PAA/SiO2 nanofiber membrane makes it a promising adsorbent for indigo carmine removal from the wastewater.

  12. Biocompatibility of poly(ethylene glycol) and poly(acrylic acid) interpenetrating network hydrogel by intrastromal implantation in rabbit cornea

    PubMed Central

    Zheng, Luo Luo; Vanchinathan, Vijay; Dalal, Roopa; Noolandi, Jaan; Waters, Dale J.; Hartmann, Laura; Cochran, Jennifer R.; Frank, Curtis W.; Yu, Charles Q.; Ta, Christopher N.

    2015-01-01

    We evaluated the biocompatibility of a poly(ethylene glycol) and poly(acrylic acid) (PEG/PAA) interpenetrating network hydrogel designed for artificial cornea in a rabbit model. PEG/PAA hydrogel measuring 6 mm in diameter was implanted in the corneal stroma of twelve rabbits. Stromal flaps were created with a microkeratome. Randomly, six rabbits were assigned to bear the implant for 2 months, two rabbits for 6 months, two rabbits for 9 months, one rabbit for 12 months, and one rabbit for 16 months. Rabbits were evaluated monthly. After the assigned period, eyes were enucleated, and corneas were processed for histology and immunohistochemistry. There were clear corneas in three of six rabbits that had implantation of hydrogel for 2 months. In the six rabbits with implant for 6 months or longer, the corneas remained clear in four. There was a high rate of epithelial defect and corneal thinning in these six rabbits. One planned 9-month rabbit developed extrusion of implant at 4 months. The cornea remained clear in the 16-month rabbit but histology revealed epithelial in-growth. Intrastromal implantation of PEG/PAA resulted in a high rate of long-term complications. PMID:25778285

  13. 40 CFR 721.6560 - Acrylic acid, polymer with substituted ethene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.6560 Acrylic acid, polymer with substituted ethene. (a) Chemical... as acrylic acid, polymer with substituted ethene (PMN P-91-521) is subject to reporting under...

  14. 40 CFR 721.10032 - Acrylic acid, polymer with substituted acrylamides (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.10032 Acrylic acid, polymer with substituted acrylamides (generic). (a... generically as acrylic acid, polymer with substituted acrylamides (PMN P-02-269) is subject to reporting...

  15. 40 CFR 721.6560 - Acrylic acid, polymer with substituted ethene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.6560 Acrylic acid, polymer with substituted ethene. (a) Chemical... as acrylic acid, polymer with substituted ethene (PMN P-91-521) is subject to reporting under...

  16. 40 CFR 721.10032 - Acrylic acid, polymer with substituted acrylamides (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.10032 Acrylic acid, polymer with substituted acrylamides (generic). (a... generically as acrylic acid, polymer with substituted acrylamides (PMN P-02-269) is subject to reporting...

  17. 40 CFR 721.6560 - Acrylic acid, polymer with substituted ethene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.6560 Acrylic acid, polymer with substituted ethene. (a) Chemical... as acrylic acid, polymer with substituted ethene (PMN P-91-521) is subject to reporting under...

  18. 40 CFR 721.10032 - Acrylic acid, polymer with substituted acrylamides (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.10032 Acrylic acid, polymer with substituted acrylamides (generic). (a... generically as acrylic acid, polymer with substituted acrylamides (PMN P-02-269) is subject to reporting...

  19. 40 CFR 721.10032 - Acrylic acid, polymer with substituted acrylamides (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.10032 Acrylic acid, polymer with substituted acrylamides (generic). (a... generically as acrylic acid, polymer with substituted acrylamides (PMN P-02-269) is subject to reporting...

  20. 40 CFR 721.6560 - Acrylic acid, polymer with substituted ethene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.6560 Acrylic acid, polymer with substituted ethene. (a) Chemical... as acrylic acid, polymer with substituted ethene (PMN P-91-521) is subject to reporting under...

  1. 40 CFR 721.10032 - Acrylic acid, polymer with substituted acrylamides (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.10032 Acrylic acid, polymer with substituted acrylamides (generic). (a... generically as acrylic acid, polymer with substituted acrylamides (PMN P-02-269) is subject to reporting...

  2. 40 CFR 721.6560 - Acrylic acid, polymer with substituted ethene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acrylic acid, polymer with substituted... Specific Chemical Substances § 721.6560 Acrylic acid, polymer with substituted ethene. (a) Chemical... as acrylic acid, polymer with substituted ethene (PMN P-91-521) is subject to reporting under...

  3. 40 CFR 721.9640 - Salt of an acrylic acid - acrylamide terpolymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Salt of an acrylic acid - acrylamide... Specific Chemical Substances § 721.9640 Salt of an acrylic acid - acrylamide terpolymer (generic). (a... generically as salt of an acrylic acid - acrylamide terpolymer (PMN P-99-817) is subject to reporting...

  4. 40 CFR 721.9640 - Salt of an acrylic acid - acrylamide terpolymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Salt of an acrylic acid - acrylamide... Specific Chemical Substances § 721.9640 Salt of an acrylic acid - acrylamide terpolymer (generic). (a... generically as salt of an acrylic acid - acrylamide terpolymer (PMN P-99-817) is subject to reporting...

  5. 40 CFR 721.9640 - Salt of an acrylic acid - acrylamide terpolymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Salt of an acrylic acid - acrylamide... Specific Chemical Substances § 721.9640 Salt of an acrylic acid - acrylamide terpolymer (generic). (a... generically as salt of an acrylic acid - acrylamide terpolymer (PMN P-99-817) is subject to reporting...

  6. 40 CFR 721.9640 - Salt of an acrylic acid - acrylamide terpolymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Salt of an acrylic acid - acrylamide... Specific Chemical Substances § 721.9640 Salt of an acrylic acid - acrylamide terpolymer (generic). (a... generically as salt of an acrylic acid - acrylamide terpolymer (PMN P-99-817) is subject to reporting...

  7. 40 CFR 721.9640 - Salt of an acrylic acid - acrylamide terpolymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Salt of an acrylic acid - acrylamide... Specific Chemical Substances § 721.9640 Salt of an acrylic acid - acrylamide terpolymer (generic). (a... generically as salt of an acrylic acid - acrylamide terpolymer (PMN P-99-817) is subject to reporting...

  8. Synthesis of lithium iron phosphate/carbon microspheres by using polyacrylic acid coated iron phosphate nanoparticles derived from iron(III) acrylate.

    PubMed

    Xu, Dongwei; He, Yan-Bing; Chu, Xiaodong; Ding, Zhaojun; Li, Baohua; He, Jianfu; Du, Hongda; Qin, Xianying; Kang, Feiyu

    2015-03-01

    Lithium iron phosphate/carbon (LiFePO4 /C) microspheres with high rate and cycling performance are synthesized from iron phosphate/polyacrylic acid (FePO4 /PAA) nanoparticles. Iron(III) acrylate is used as a precursor for both the iron and carbon sources. FePO4 nanoparticles are first produced by a coprecipitation reaction. The byproduct, acrylic acid ions, is polymerized in situ to form a uniform PAA layer on the surface of the FePO4 nanoparticles. The as-prepared LiFePO4 /C microspheres are composed of primary nanoparticles with sizes of 40-50 nm. The nanoparticles are fully coated with a thin, uniform carbon layer derived from the decomposition of the PAA layer. The uniform carbon-coating layer cooperates with interstitial and boundary carbon derived from sucrose successfully to construct an excellent interconnecting conductive network in the microspheres. As a result of the unique structure, the as-prepared LiFePO4 /C microspheres display both high electronic and ionic conductivities, which contribute to their high rate performance (162.9 mAh g(-1) at 0.1C and 126.1 mAh g(-1) at 5C) and excellent cycling stability (97.1% of capacity retention after 500 cycles at 5C/5C). PMID:25469674

  9. Synthesis of lithium iron phosphate/carbon microspheres by using polyacrylic acid coated iron phosphate nanoparticles derived from iron(III) acrylate.

    PubMed

    Xu, Dongwei; He, Yan-Bing; Chu, Xiaodong; Ding, Zhaojun; Li, Baohua; He, Jianfu; Du, Hongda; Qin, Xianying; Kang, Feiyu

    2015-03-01

    Lithium iron phosphate/carbon (LiFePO4 /C) microspheres with high rate and cycling performance are synthesized from iron phosphate/polyacrylic acid (FePO4 /PAA) nanoparticles. Iron(III) acrylate is used as a precursor for both the iron and carbon sources. FePO4 nanoparticles are first produced by a coprecipitation reaction. The byproduct, acrylic acid ions, is polymerized in situ to form a uniform PAA layer on the surface of the FePO4 nanoparticles. The as-prepared LiFePO4 /C microspheres are composed of primary nanoparticles with sizes of 40-50 nm. The nanoparticles are fully coated with a thin, uniform carbon layer derived from the decomposition of the PAA layer. The uniform carbon-coating layer cooperates with interstitial and boundary carbon derived from sucrose successfully to construct an excellent interconnecting conductive network in the microspheres. As a result of the unique structure, the as-prepared LiFePO4 /C microspheres display both high electronic and ionic conductivities, which contribute to their high rate performance (162.9 mAh g(-1) at 0.1C and 126.1 mAh g(-1) at 5C) and excellent cycling stability (97.1% of capacity retention after 500 cycles at 5C/5C).

  10. 40 CFR 721.321 - Substituted acrylamides and acrylic acid copolymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted acrylamides and acrylic... New Uses for Specific Chemical Substances § 721.321 Substituted acrylamides and acrylic acid copolymer... identified generically as substituted acrylamides and acrylic acid copolymer (PMN P-00-0490) is subject...

  11. 40 CFR 721.321 - Substituted acrylamides and acrylic acid copolymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted acrylamides and acrylic... New Uses for Specific Chemical Substances § 721.321 Substituted acrylamides and acrylic acid copolymer... identified generically as substituted acrylamides and acrylic acid copolymer (PMN P-00-0490) is subject...

  12. 40 CFR 721.321 - Substituted acrylamides and acrylic acid copolymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted acrylamides and acrylic... New Uses for Specific Chemical Substances § 721.321 Substituted acrylamides and acrylic acid copolymer... identified generically as substituted acrylamides and acrylic acid copolymer (PMN P-00-0490) is subject...

  13. 40 CFR 721.321 - Substituted acrylamides and acrylic acid copolymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted acrylamides and acrylic... New Uses for Specific Chemical Substances § 721.321 Substituted acrylamides and acrylic acid copolymer... identified generically as substituted acrylamides and acrylic acid copolymer (PMN P-00-0490) is subject...

  14. 40 CFR 721.321 - Substituted acrylamides and acrylic acid copolymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Substituted acrylamides and acrylic... New Uses for Specific Chemical Substances § 721.321 Substituted acrylamides and acrylic acid copolymer... identified generically as substituted acrylamides and acrylic acid copolymer (PMN P-00-0490) is subject...

  15. Fracture Mechanisms of Layer-By-Layer Polyurethane/Poly(Acrylic Acid) Nanocomposite

    NASA Astrophysics Data System (ADS)

    Kheng, Eugene R.

    A layer-by-layer(LBL) manufactured material is examined in detail in this thesis. Improvements are made to the method of its manufacture. Efforts are made to understand its fracture mechanisms and take advantage of these fracture mechanisms in the absorption of impact energy. A novel series of experiments has been performed on LBL manufactured thin films to demonstrate their unique fracture mechanisms. Polyurethane/Poly(Acrylic Acid) (PU/PAA) and PU/PAA/(PU/Clay)5 nanocomposite films readily undergo Interlaminar mode II fracture, because of the relatively weak elctrostatic bonds between monolayers. Tensile tests performed while under observation by a scanning electron microscope demonstrate the tendency of these nanocomposite films to undergo interlaminar mode II fracture even when loads are applied in the plane of nanocomposite film. It is concluded that these mechanisms of energy dissipation are responsible for the enhanced toughness of these films when used as layers between glass blocks in the prevention of impact damage to the glass. A novel automated manufacturing facility has been designed and built to deposit large sheets of Layer-by-Layer nanocomposite film. These large sheets are incorporated into a borosillicate glass composite in order to compare the ballistic characteristics of LBL PU based nanocomposite films to a single cast layer of polyurethane. It is demonstrated that shear fracture is the mode of failure in the blocks containing the nanocomposite film. The shear fracture surface in the nanocomposite after it has undergone a ballistic impact is characterized. Additional experiments are performed to characterize the interlaminar fracture stresses and toughnesses of the nanocomposite LBL layers, to assist in the implementation of a numerical crack band model that describes the nanocomposite film. The computational model predicts the failure of the ballistic nanocomposite samples, and the predicted V50 velocity is found to be in good agreement with

  16. Transport in Porous Media of Poly(Acrylic Acid) Coated Ferrihydrite Nanoparticles

    NASA Astrophysics Data System (ADS)

    Jaffe, P. R.; Xiang, A.; Koel, B. E.

    2012-12-01

    Augmentation of soils with iron to enhance biological processes such as uranium reduction via iron reducing bacteria, e.g., Geobacter sp., might be achieved via the injection of iron nanoparticles into the subsurface. The challenge is to make these nanoparticles transportable in the subsurface while not affecting the iron bioavailability. Poorly crystallized 2-line ferrihydrite iron oxide nanoparticles were synthesized and coated with different amounts of poly(acrylic acid) polymers (Na-PAA6K or Na-PAA140K). Analyses were then performed on these particles, including sorption/desorption of the polymer onto the iron nanoparticles, particle size, zeta potential, transport in sand and soil columns, and bioavailabity of the Fe(III) in the absence and presence of the coating to iron reducing organisms. Results showed that at pH values of environmental relevance, the zeta potential of the particles varied from about 3 mV (pH=8.2) for the non-coated particles to about -30 mV for the particles coated with the polymers to their highest sorption capacity. The coated particle diameter was shown to be in the range of 200 nm. Column transport experiments showed that for the highest polymer coating the nanoparticle breakthrough was virtually identical to that of bromide, while significant filtration was observed for particles with an intermediate coating, and complete particle removal via filtration was observed for the non-coated particles. These results held for sand as well as for soil, which had been previously characterized, from a field site at Rifle, CO. Bioavailability experiments showed no difference in the iron reduction rate between the untreated and treated nanoparticles. These results show that it is possible to manufacture iron nanoparticles to enhance biological iron reduction, and that the transport properties of these treated particles is tunable so that a desired retention in the porous medium can be achieved.

  17. Hydrogen-bonding-induced complexation of polydimethylsiloxane-graft-poly(ethylene oxide) and poly(acrylic acid)-block-polyacrylonitrile micelles in water.

    PubMed

    Hu, Aijuan; Cui, Yushuang; Wei, Xiaoling; Lu, Zaijun; Ngai, To

    2010-09-21

    Polydimethylsiloxane-graft-poly(ethylene oxide) (PDMS-g-PEO) copolymers form micelles in water with PDMS as the core and PEO as the corona. The introduction of poly(acrylic acid)-block-polyacrylonitrile (PAA-b-PAN) block copolymers in water leads to the formation of micellar complexes due to the hydrogen bonding between carboxyl groups and ether oxygens among the PAA and PEO chains in the corona of the micelles. The effects of pH, molar ratios (r) of PAA/PEO, and the standing time on the directly mixing these two micelles in water have been investigated using laser light scattering (LLS) and transmission electron microscopy (TEM). Our results showed that the complexation between PAA and PEO in the corona was greatly enhanced at a pH below 3.5. For a fixed pH value, the interactions between these two micelles in water were governed by the value of r. At r < ∼0.6, mixing the two micelles in water resulted in a large floccule because the smaller PAA-b-PAN micelles act as physical cross-links, which are absorbed onto one PDMS-g-PEO micelle and simultaneously bonded to PEO chains on the other micelles, forming bridges and causing flocculation. At ∼0.6 < r < ∼1.2, the mixing led to stable micellar complexes with a layer of PAA-b-PAN micelles absorbed onto the initial PDMS-g-PEO micelles. At r > ∼1.2, the resultant micellar complexes first remained stable, but they precipitated from solution after a long time standing.

  18. Unusually Stable Hysteresis in the pH-Response of Poly(Acrylic Acid) Brushes Confined within Nanoporous Block Polymer Thin Films.

    PubMed

    Weidman, Jacob L; Mulvenna, Ryan A; Boudouris, Bryan W; Phillip, William A

    2016-06-01

    Stimuli-responsive soft materials are a highly studied field due to their wide-ranging applications; however, only a small group of these materials display hysteretic responses to stimuli. Moreover, previous reports of this behavior have typically shown it to be short-lived. In this work, poly(acrylic acid) (PAA) chains at extremely high grafting densities and confined in nanoscale pores displayed a unique long-lived hysteretic behavior caused by their ability to form a metastable hydrogen bond network. Hydraulic permeability measurements demonstrated that the conformation of the PAA chains exhibited a hysteretic dependence on pH, where different effective pore diameters arose in a pH range of 3 to 8, as determined by the pH of the previous environment. Further studies using Fourier transform infrared (FTIR) spectroscopy demonstrated that the fraction of ionized PAA moieties depended on the thin film history; this was corroborated by metal adsorption capacity, which demonstrated the same pH dependence. This hysteresis was shown to be persistent, enduring for days, in a manner unlike most other systems. The hypothesis that hydrogen bonding among PAA units contributed to the hysteretic behavior was supported by experiments with a urea solution, which disrupted the metastable hydrogen bonded state of PAA toward its ionized state. The ability of PAA to hydrogen bond within these confined pores results in a stable and tunable hysteresis not previously observed in homopolymer materials. An enhanced understanding of the polymer chemistry and physics governing this hysteresis gives insight into the design and manipulation of next-generation sensors and gating materials in nanoscale applications.

  19. Preparation of chitosan/poly(acrylic acid) magnetic composite microspheres and applications in the removal of copper(II) ions from aqueous solutions.

    PubMed

    Yan, Han; Yang, Lingyun; Yang, Zhen; Yang, Hu; Li, Aimin; Cheng, Rongshi

    2012-08-30

    In this current work, the magnetic composite microspheres (MCM), consisting of Fe(3)O(4) nanoparticles and poly(acrylic acid) (PAA) blended chitosan (CS), were prepared successfully by a simple method, co-precipitation of the compounds in alkaline solution. SEM, FTIR and TG techniques have been applied to investigate the structures of the MCM materials. The vibrating-sample magnetometer (VSM) measurement illustrated a paramagnetic property as well as a fast magnetic response, which indicated the significant separability of the MCM in the aqueous suspensions. Then, the MCM materials were employed as absorbents for removal of copper(II) (Cu(II)) ions from aqueous solutions. The fundamental adsorption behaviors of MCM were studied also. Experimental results revealed that the CS/PAA-MCM had greater adsorption capacity than CS-MCM, and PAA played an important role for the adsorption of Cu(II) ions. Moreover, the adsorption isotherms were all well described by the Langmuir model, while the adsorption kinetics followed the pseudo-second order equation. Furthermore, the adsorbent could be easily regenerated at lower pH and reused almost without any loss of adsorption capacity. On the contrary, the Cu(II) ions loaded CS-MCM and CS/PAA-MCM were stable enough at pH higher than 4.0, and both exhibited efficient phosphate removal with maximal uptakes around 63.0 and 108.0 mg Pg(-1), respectively. PMID:22749139

  20. Poly(acrylic acid) modified lanthanide-doped GdVO4 hollow spheres for up-conversion cell imaging, MRI and pH-dependent drug release.

    PubMed

    Kang, Xiaojiao; Yang, Dongmei; Dai, Yunlu; Shang, Mengmeng; Cheng, Ziyong; Zhang, Xiao; Lian, Hongzhou; Ma, Ping'an; Lin, Jun

    2013-01-01

    In this study, multifunctional poly(acrylic acid) modified lanthanide-doped GdVO(4) nanocomposites [PAA@GdVO(4): Ln(3+) (Ln = Yb/Er, Yb/Ho, Yb/Tm)] were constructed by filling PAA hydrogel into GdVO(4) hollow spheres via photoinduced polymerization. The up-conversion (UC) emission colors (green, red and blue) can be tuned by changing the codopant compositions in the matrices. The composites have potential applications as bio-probes for cell imaging. Meanwhile, the hybrid spheres can act as T(1) contrast agents for magnetic resonance imaging (MRI) owing to the existence of Gd(3+) ions on the surface of composites. Due to the nature of PAA, DOX-loaded PAA@GdVO(4):Yb(3+)/Er(3+) system exhibits pH-dependent drug releasing kinetics. A lower pH offers a faster drug release rate. Such character makes the loaded DOX easily released at cancer cells. The cell uptake process of drug-loaded composites was observed by using confocal laser scanning microscopy (CLSM). The results indicate the potential application of the multifunctional composites as theragnostics (effective bimodal imaging probes and pH-responsive drug carriers).

  1. pH-responsive controlled-release fertilizer with water retention via atom transfer radical polymerization of acrylic acid on mussel-inspired initiator.

    PubMed

    Ma, Zhi-yuan; Jia, Xin; Zhang, Guo-xiang; Hu, Jia-mei; Zhang, Xiu-lan; Liu, Zhi-yong; Wang, He-yun; Zhou, Feng

    2013-06-12

    This work reports a polydopamine-graft-poly(acrylic acid) (Pdop-g-PAA)-coated controlled-release multi-element compound fertilizer with water-retention function by a combination of mussel-inspired chemistry and surface-initiated atom transfer radical polymerization (SI-ATRP) techniques for the first time. The morphology and composition of the products were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and inductively coupled plasma (ICP) emission spectrometry. The results revealed that the stimuli-responsive layer formed by a Pdop inner layer and a PAA outer corona exhibit outstanding selective permeability to charged nutrients and the release rate of encapsulated elements can be tailored by the pH values. At low pH, the Pdop-g-PAA layer can reduce nutrient loss, and at high pH, the coating restrains transportation of negative nutrients but favors the release of cations. Moreover, PAA brushes provide good water-retention property. This Pdop-graft-polymer brushes coating will be effective and promising in the research and development of multi-functional controlled-release fertilizer. PMID:23692274

  2. pH-responsive controlled-release fertilizer with water retention via atom transfer radical polymerization of acrylic acid on mussel-inspired initiator.

    PubMed

    Ma, Zhi-yuan; Jia, Xin; Zhang, Guo-xiang; Hu, Jia-mei; Zhang, Xiu-lan; Liu, Zhi-yong; Wang, He-yun; Zhou, Feng

    2013-06-12

    This work reports a polydopamine-graft-poly(acrylic acid) (Pdop-g-PAA)-coated controlled-release multi-element compound fertilizer with water-retention function by a combination of mussel-inspired chemistry and surface-initiated atom transfer radical polymerization (SI-ATRP) techniques for the first time. The morphology and composition of the products were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric analysis (TGA), gel permeation chromatography (GPC), and inductively coupled plasma (ICP) emission spectrometry. The results revealed that the stimuli-responsive layer formed by a Pdop inner layer and a PAA outer corona exhibit outstanding selective permeability to charged nutrients and the release rate of encapsulated elements can be tailored by the pH values. At low pH, the Pdop-g-PAA layer can reduce nutrient loss, and at high pH, the coating restrains transportation of negative nutrients but favors the release of cations. Moreover, PAA brushes provide good water-retention property. This Pdop-graft-polymer brushes coating will be effective and promising in the research and development of multi-functional controlled-release fertilizer.

  3. Biosynthetic pathway for acrylic acid from glycerol in recombinant Escherichia coli.

    PubMed

    Tong, Wenhua; Xu, Ying; Xian, Mo; Niu, Wei; Guo, Jiantao; Liu, Huizhou; Zhao, Guang

    2016-06-01

    Acrylic acid is an important industrial feedstock. In this study, a de novo acrylate biosynthetic pathway from inexpensive carbon source glycerol was constructed in Escherichia coli. The acrylic acid was produced from glycerol via 3-hydroxypropionaldehyde, 3-hydroxypropionyl-CoA, and acrylyl-CoA. The acrylate production was improved by screening and site-directed mutagenesis of key enzyme enoyl-CoA hydratase and chromosomal integration of some exogenous genes. Finally, our recombinant strain produced 37.7 mg/L acrylic acid under shaking flask conditions. Although the acrylate production is low, our study shows feasibility of engineering an acrylate biosynthetic pathway from inexpensive carbon source. Furthermore, the reasons for limited acrylate production and further strain optimization that should be performed in the future were also discussed. PMID:26782744

  4. A New Process for Acrylic Acid Synthesis by Fermentative Process

    NASA Astrophysics Data System (ADS)

    Lunelli, B. H.; Duarte, E. R.; de Toledo, E. C. Vasco; Wolf Maciel, M. R.; Maciel Filho, R.

    With the synthesis of chemical products through biotechnological processes, it is possible to discover and to explore innumerable routes that can be used to obtain products of high addes value. Each route may have particular advantages in obtaining a desired product, compared with others, especially in terms of yield, productivity, easiness to separate the product, economy, and environmental impact. The purpose of this work is the development of a deterministic model for the biochemical synthesis of acrylic acid in order to explore an alternative process. The model is built-up with the tubular reactor equations together with the kinetic representation based on the structured model. The proposed process makes possible to obtain acrylic acid continuously from the sugar cane fermentation.

  5. Precipitation polymerization of acrylic acid in supercritical carbon dioxide

    SciTech Connect

    Romack, T.J.; Maury, E.E.; DeSimone, J.M.

    1995-02-13

    Increasing concern regarding the dissemination of chemical waste (both aqueous and organic) into their environment has prompted considerable interest in new technologies aimed at reducing current waste streams. Processes utilizing carbon dioxide in lieu of conventional solvents for chemical manufacturing and processing provide a viable route to achieving near-zero waste production for these important industries. The authors report the successful precipitation polymerization of acrylic acid in supercritical carbon dioxide at pressure ranging from 125 to 345 bar utilizing AIBN as a free radical initiator. Analyses by gel permeation chromatography (GPC) and scanning electron microscopy (SEM) indicate that for the pressure range studied there is no appreciable effect on product molecular weight, molecular weight distribution, or particle size or morphology. In addition, effective molecular weight control was demonstrated for precipitation polymerizations of acrylic acid in CO{sub 2} through the use of ethyl mercaptan as a chain transfer agent.

  6. Polymerization of acrylic acid using atmospheric pressure DBD plasma jet

    NASA Astrophysics Data System (ADS)

    Bashir, M.; Bashir, S.

    2016-08-01

    In this paper polymerization of acrylic acid was performed using non thermal atmospheric pressure plasma jet technology. The goal of this study is to deposit organic functional coatings for biomedical applications using a low cost and rapid growth rate plasma jet technique. The monomer solution of acrylic acid was vaporized and then fed into the argon plasma for coating. The discharge was powered using a laboratory made power supply operating with sinusoidal voltage signals at a frequency of 10 kHz. The optical emission spectra were collected in order to get insight into the plasma chemistry during deposition process. The coatings were characterized using Fourier transform infrared spectroscopy, atomic force microscopy and growth rates analysis. A high retention of carboxylic functional groups of the monomer was observed at the surface deposited using this low power technique.

  7. Controlled release camptothecin tablets based on pluronic and poly(acrylic acid) copolymer. Effect of fabrication technique on drug stability, tablet structure, and release mode.

    PubMed

    Bromberg, Lev; Hatton, T Alan; Barreiro-Iglesias, Rafael; Alvarez-Lorenzo, Carmen; Concheiro, Angel

    2007-06-01

    Poly(ethylene oxide)-b-poly(propylene oxide)-b-(polyethylene oxide)-g-poly(acrylic acid), a graft-comb copolymer of Pluronic 127 and poly(acrylic acid) (Pluronic-PAA), was explored as an excipient for tablet dosage form of camptothecin (CPT). The tablets were prepared by either direct compression of the drug-polymer physical blend, suspension in ethanol followed by evaporation, or compression after kneading and characterized with respect to their physical structures, drug stability, and release behavior. Porosity and water uptake rate were strongly dependent on the fabrication procedure, ranking in the order: direct compression of physical blend > compression after suspension/evaporation in ethanol > compression after kneading. Tablets prepared by compression of physical blends swelled in water with a rapid surface gel layer formation that impeded swelling and disintegration of the tablets core. These tablets were able to sustain the CPT release for a period of time longer than those observed with the tablets made by either suspension/evaporation or kneading, which disintegrated within a few minutes. Despite the tablet disintegration, the CPT release was impeded for at least 6 hr, which was attributed to the ability of the Pluronic-PAA copolymers to form micellar aggregates at the hydrated surface of the particles. Physical mixing did not alter the fraction of CPT being in the pharmaceutically active lactone form, whilst the preparation of the tablets by the other two methods caused a significant reduction in the lactone form content. Tablets prepared from the physical blends demonstrated CPT release rates increasing with the pH due to the PAA ionization leading to the increase in the rate and extent of the tablet swelling. The results obtained demonstrate the potential of the Pluronic-PAA copolymers for the oral administration of chemotherapeutic agents. PMID:17613025

  8. Efficient removal of malachite green dye using biodegradable graft copolymer derived from amylopectin and poly(acrylic acid).

    PubMed

    Sarkar, Amit Kumar; Pal, Aniruddha; Ghorai, Soumitra; Mandre, N R; Pal, Sagar

    2014-10-13

    This article reports on the application of a high performance biodegradable adsorbent based on amylopectin and poly(acrylic acid) (AP-g-PAA) for removal of toxic malachite green dye (MG) from aqueous solution. The graft copolymer has been synthesized and characterized using various techniques including FTIR, GPC, SEM and XRD analyses. Biodegradation study suggests that the co-polymer is biodegradable in nature. The adsorbent shows excellent potential (Qmax, 352.11 mg g(-1); 99.05% of MG has been removed within 30 min) for removal of MG from aqueous solution. It has been observed that point to zero charge (pzc) of graft copolymer plays significant role in adsorption efficacy. The adsorption kinetics and isotherm follow pseudo-second order and Langmuir isotherm models, respectively. Thermodynamics parameters suggest that the process of dye uptake is spontaneous. Finally desorption study shows excellent regeneration efficiency of adsorbent.

  9. Cellular Response to Linear and Branched Poly(acrylic acid).

    PubMed

    Whitty, Elizabeth G; Maniego, Alison R; Bentwitch, Sharon A; Guillaneuf, Yohann; Jones, Mark R; Gaborieau, Marianne; Castignolles, Patrice

    2015-12-01

    Poly(acrylic acid-co-sodium acrylate) (PNaA) is a pH-responsive polymer with potential in anticancer drug delivery. The cytotoxicity and intracellular effects of 3-arm star, hyperbranched and linear PNaA were investigated with L1210 progenitor leukemia cells and L6 myoblast cells. Free solution capillary electrophoresis demonstrated interactions of PNaA with serum proteins. In a 72 h MTT assay most PNaAs exhibited a IC50 between 7 and 14 mmol L(-1), showing that precipitation may be a sufficient purification for PNaA dilute solutions. Dialyzed 3-arm star and hyperbranched PNaA caused an increase in L6 cell viability, challenging the suitability of MTT as cytotoxicity assay for PNaA. Fluorescent confocal microscopy revealed merging of cellular lipids after exposure to PNaA, likely caused by serum starvation.

  10. Poly(acrylic acid)/poly(ethylene glycol) adduct for attaining multifunctional cellulosic fabrics.

    PubMed

    Ibrahim, N A; Amr, A; Eid, B M; Mohamed, Z E; Fahmy, H M

    2012-06-20

    Aqueous polymerization of partially neutralized acrylic acid (AA) along with polyethylene glycol (PEG-600) at AA/PEG-600 mass ratio 3/1 using ammonium persulfate as initiator under proper conditions results in formation of PAA/PEG-600 adduct. The structure of the adduct was confirmed by FT-IR spectra. The potential applications of the prepared adduct in: sizing, durable hand building of cotton cellulose, as well as in functional finishing of cellulose containing fabrics, i.e. cotton, viscose and cotton/polyester, with Ag- or TiO2-nanoparticles were investigated. The modified substrates using the prepared adduct showed a remarkable improvement in their sizing, hand building and/or functional properties, i.e. antibacterial, anti-UV, and self cleaning, in addition to durability to wash. TEM images of the prepared nano-particles, SEM images of the untreated and treated substrates, as well as EDX spectra to analyze the surface elemental compositions were examined. The tentative mechanisms were also suggested. PMID:24750770

  11. Highly hydrophilic ultra-high molecular weight polyethylene powder and film prepared by radiation grafting of acrylic acid

    NASA Astrophysics Data System (ADS)

    Wang, Honglong.; Xu, Lu.; Li, Rong.; Pang, Lijuan.; Hu, Jiangtao.; Wang, Mouhua.; Wu, Guozhong.

    2016-09-01

    The surface properties of ultra-high molecular weight polyethylene (UHMWPE) are very important for its use in engineering or composites. In this work, hydrophilic UHMWPE powder and film were prepared by γ-ray pre-irradiation grafting of acrylic acid (AA) and further neutralization with sodium hydroxide solution. Variations in the chemical structure, grafting yield and hydrophilicity were investigated and compared. FT-IR and XPS analysis results showed that AA was successfully grafted onto UHMWPE powder and film; the powder was more suitable for the grafting reaction in 1 wt% AA solution than the film. Given a dose of 300 kGy, the grafting yield of AA was ∼5.7% for the powder but ∼0.8% for the film under identical conditions. Radiation grafting of a small amount of AA significantly improved the hydrophilicity of UHMWPE. The water contact angle of the UHMWPE-g-PAA powder with a grafting yield of AA at ∼5.7% decreased from 110.2° to 68.2°. Moreover, the grafting powder (UHMWPE-g-PAA) exhibited good dispersion ability in water.

  12. Graphene oxide/poly(acrylic acid)/gelatin nanocomposite hydrogel: experimental and numerical validation of hyperelastic model.

    PubMed

    Faghihi, Shahab; Karimi, Alireza; Jamadi, Mahsa; Imani, Rana; Salarian, Reza

    2014-05-01

    Owing to excellent thermal and mechanical properties, graphene-based nanomaterials have recently attracted intensive attention for a wide range of applications, including biosensors, bioseparation, drug release vehicle, and tissue engineering. In this study, the effects of graphene oxide nanosheet (GONS) content on the linear (tensile strength and strain) and nonlinear (hyperelastic coefficients) mechanical properties of poly(acrylic acid) (PAA)/gelatin (Gel) hydrogels are evaluated. The GONS with different content (0.1, 0.3, and 0.5 wt.%) is added into the prepared PAA/Gel hydrogels and composite hydrogels are subjected to a series of tensile and stress relaxation tests. Hyperelastic strain energy density functions (SEDFs) are calibrated using uniaxial experimental data. The potential ability of different hyperelastic constitutive equations (Neo-Hookean, Yeoh, and Mooney-Rivlin) to define the nonlinear mechanical behavior of hydrogels is verified by finite element (FE) simulations. The results show that the tensile strength (71%) and elongation at break (26%) of composite hydrogels are significantly increased by the addition of GONS (0.3 wt.%). The experimental data is well fitted with those predicted by the FE models. The Yeoh material model accurately defines the nonlinear behavior of hydrogels which can be used for further biomechanical simulations of hydrogels. This finding might have implications not only for the improvement of the mechanical properties of composite hydrogels but also for the fabrication of polymeric substrate materials suitable for tissue engineering applications.

  13. LC50 values for rats acutely exposed to vapors of acrylic and methacrylic acid esters

    SciTech Connect

    Oberly, R.; Tansy, M.F.

    1985-01-01

    Acute exposure studies were conducted using adult male Sprague-Dawley rats to obtain LC50/24 concentrations for the common esters of acrylic and methacrylic acids. The order of acute toxicity was determined to be methyl acrylate > ethyl acrylate > butyl acrylate > butyl methacrylate > methyl methacrylate > ethyl methacrylate. Four-hour daily exposures (excluding weekends) of young adult male rats to 110 ppm methyl acrylate in air over a period of 32 d failed to produce significant differences in body or tissue weights, blood chemistries, gross metabolic performance, and spontaneous small-intestinal motor activities when compared with a sham-exposed group.

  14. Direct fermentation route for the production of acrylic acid.

    PubMed

    Chu, Hun Su; Ahn, Jin-Ho; Yun, Jiae; Choi, In Suk; Nam, Tae-Wook; Cho, Kwang Myung

    2015-11-01

    There have been growing concerns regarding the limited fossil resources and global climate changes resulting from modern civilization. Currently, finding renewable alternatives to conventional petrochemical processes has become one of the major focus areas of the global chemical industry sector. Since over 4.2 million tons of acrylic acid (AA) is annually employed for the manufacture of various products via petrochemical processes, this chemical has been the target of efforts to replace the petrochemical route by ecofriendly processes. However, there has been limited success in developing an approach combining the biological production of 3-hydroxypropionic acid (3-HP) and its chemical conversion to AA. Here, we report the first direct fermentative route for producing 0.12 g/L of AA from glucose via 3-HP, 3-HP-CoA, and Acryloyl-CoA, leading to a strain of Escherichia coli capable of directly producing acrylic acid. This route was developed through extensive screening of key enzymes and designing a novel metabolic pathway for AA. PMID:26319589

  15. Freshwater dispersion stability of PAA-stabilised cerium oxide nanoparticles and toxicity towards Pseudokirchneriella subcapitata.

    PubMed

    Booth, Andy; Størseth, Trond; Altin, Dag; Fornara, Andrea; Ahniyaz, Anwar; Jungnickel, Harald; Laux, Peter; Luch, Andreas; Sørensen, Lisbet

    2015-02-01

    An aqueous dispersion of poly (acrylic acid)-stabilised cerium oxide (CeO₂) nanoparticles (PAA-CeO₂) was evaluated for its stability in a range of freshwater ecotoxicity media (MHRW, TG 201 and M7), with and without natural organic matter (NOM). In a 15 day dispersion stability study, PAA-CeO₂ did not undergo significant aggregation in any media type. Zeta potential varied between media types and was influenced by PAA-CeO₂ concentration, but remained constant over 15 days. NOM had no influence on PAA-CeO₂ aggregation or zeta potential. The ecotoxicity of the PAA-CeO₂ dispersion was investigated in 72 h algal growth inhibition tests using the freshwater microalgae Pseudokirchneriella subcapitata. PAA-CeO₂ EC₅₀ values for growth inhibition (GI; 0.024 mg/L) were 2-3 orders of magnitude lower than pristine CeO₂ EC₅₀ values reported in the literature. The concentration of dissolved cerium (Ce(3+)/Ce(4+)) in PAA-CeO₂ exposure suspensions was very low, ranging between 0.5 and 5.6 μg/L. Free PAA concentration in the exposure solutions (0.0096-0.0384 mg/L) was significantly lower than the EC10 growth inhibition (47.7 mg/L) value of pure PAA, indicating that free PAA did not contribute to the observed toxicity. Elemental analysis indicated that up to 38% of the total Cerium becomes directly associated with the algal cells during the 72 h exposure. TOF-SIMS analysis of algal cell wall compounds indicated three different modes of action, including a significant oxidative stress response to PAA-CeO₂ exposure. In contrast to pristine CeO₂ nanoparticles, which rapidly aggregate in standard ecotoxicity media, PAA-stabilised CeO₂ nanoparticles remain dispersed and available to water column species. Interaction of PAA with cell wall components, which could be responsible for the observed biomarker alterations, could not be excluded. This study indicates that the increased dispersion stability of PAA-CeO₂ leads to an increase in toxicity compared to

  16. Graft copolymerization of acrylic acid onto polyamide fibers

    NASA Astrophysics Data System (ADS)

    Makhlouf, Chahira; Marais, Stéphane; Roudesli, Sadok

    2007-04-01

    The grafting of acrylic acid (AA) monomer (CH 2dbnd CH sbnd COOH) on polyamide 6.6 monofilaments (PA 6.6) using benzoyl peroxide (BPO) as initiator was carried out in order to enhance the hydrophilic nature of fibers. The grafting rate depends on the AA concentration, the BPO concentration, the time and the temperature of reaction. The best conditions for optimum rate of grafting were obtained with a AA concentration of 0.5 M, a BPO concentration of 0.03 M, a reaction temperature of T = 85 °C and a reaction time of 120 mn. The fiber surface has been investigated by many experimental techniques of characterization such as Fourier transform infrared spectroscopy (FTIR), calorimetric analysis (DSC), scanning electron microscopy (SEM), and contact angle measurements. The effect of grafting of acrylic acid onto PA 6.6 fibers on their moisture and mechanical resistances was analyzed from water sorption and elongation at break measurements. The analysis of the experimental data shows clearly the efficiency of the grafting reaction used, leading to a significant increase of the hydrophilic character of the PA 6.6 surface.

  17. Toward "stable-on-the-table" enzymes: improving key properties of catalase by covalent conjugation with poly(acrylic acid).

    PubMed

    Riccardi, Caterina M; Cole, Kyle S; Benson, Kyle R; Ward, Jessamyn R; Bassett, Kayla M; Zhang, Yiren; Zore, Omkar V; Stromer, Bobbi; Kasi, Rajeswari M; Kumar, Challa V

    2014-08-20

    Several key properties of catalase such as thermal stability, resistance to protease degradation, and resistance to ascorbate inhibition were improved, while retaining its structure and activity, by conjugation to poly(acrylic acid) (PAA, Mw 8000) via carbodiimide chemistry where the amine groups on the protein are appended to the carboxyl groups of the polymer. Catalase conjugation was examined at three different pH values (pH 5.0, 6.0, and 7.0) and at three distinct mole ratios (1:100, 1:500, and 1:1000) of catalase to PAA at each reaction pH. The corresponding products are labeled as Cat-PAA(x)-y, where x is the protein to polymer mole ratio and y is the pH used for the synthesis. The coupling reaction consumed about 60-70% of the primary amines on the catalase; all samples were completely water-soluble and formed nanogels, as evidenced by gel electrophoresis and electron microscopy. The UV circular dichroism (CD) spectra indicated substantial retention of protein secondary structure for all samples, which increased to 100% with increasing pH of the synthesis and polymer mole fraction. Soret CD bands of all samples indicated loss of ∼50% of band intensities, independent of the reaction pH. Catalytic activities of the conjugates increased with increasing synthesis pH, where 55-80% and 90-100% activity was retained for all samples synthesized at pH 5.0 and pH 7.0, respectively, and the Km or Vmax values of Cat-PAA(100)-7 did not differ significantly from those of the free enzyme. All conjugates synthesized at pH 7.0 were thermally stable even when heated to ∼85-90 °C, while native catalase denatured between 55 and 65 °C. All conjugates retained 40-90% of their original activities even after storing for 10 weeks at 8 °C, while unmodified catalase lost all of its activity within 2 weeks, under similar storage conditions. Interestingly, PAA surrounding catalase limited access to the enzyme from large molecules like proteases and significantly increased

  18. Electroactive behavior of poly(acrylic acid) grafted poly(vinyl alcohol) samples, their synthesis using a Ce(IV) glucose redox system and their characterization

    NASA Astrophysics Data System (ADS)

    Kurkuri, Mahaveer D.; Lee, Jae-Rock; Han, Jae Hung; Lee, In

    2006-04-01

    Grafted copolymers of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) were prepared using a Ce(IV) glucose redox initiator by free radical polymerization. Three grafted copolymers having 20%, 50% and 80% grafting were selected for this study. Thus-modified polymer was characterized by means of Fourier transform infrared spectra, 1H NMR, gel permeation chromatography, thermogravimetric analysis and universal testing machine approaches. The membranes were prepared by a solution casting method, where the cross-linking process was performed through the in situ addition of glutaraldehyde and hydrochloric acid as the cross-linking agent and catalyst respectively. The following four membranes were prepared: (i) pure PVA; (ii) 20% grafted PVA; (iii) 50% grafted PVA; (iv) 80% grafted PVA. The membranes obtained were employed in the electroactive behavior study under a DC electric stimulus in different concentrations of electrolyte. The equilibrium bending angles (EBA) of these polymers were studied with respect to time, poly(acrylic acid) content, electric voltage applied across the polymer and ionic strength of the electrolyte used. Experimental results show stable reversibility of the bending behavior of these polymers under an applied DC electric field. The EBA increased with increase in the applied electric voltage and poly(acrylic acid) content within the polymer.

  19. "Stable-on-the-Table" Biosensors: Hemoglobin-Poly (Acrylic Acid) Nanogel BioElectrodes with High Thermal Stability and Enhanced Electroactivity.

    PubMed

    Ghimire, Ananta; Zore, Omkar V; Thilakarathne, Vindya K; Briand, Victoria A; Lenehan, Patrick J; Lei, Yu; Kasi, Rajeswari M; Kumar, Challa V

    2015-01-01

    In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, M(W) 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17-20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at -0.279 and -0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 μM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications. PMID:26393601

  20. “Stable-on-the-Table” Biosensors: Hemoglobin-Poly (Acrylic Acid) Nanogel BioElectrodes with High Thermal Stability and Enhanced Electroactivity

    PubMed Central

    Ghimire, Ananta; Zore, Omkar V.; Thilakarathne, Vindya K.; Briand, Victoria A.; Lenehan, Patrick J.; Lei, Yu; Kasi, Rajeswari M.; Kumar, Challa V.

    2015-01-01

    In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, MW 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17–20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at −0.279 and −0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 μM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications. PMID:26393601

  1. "Stable-on-the-Table" Biosensors: Hemoglobin-Poly (Acrylic Acid) Nanogel BioElectrodes with High Thermal Stability and Enhanced Electroactivity.

    PubMed

    Ghimire, Ananta; Zore, Omkar V; Thilakarathne, Vindya K; Briand, Victoria A; Lenehan, Patrick J; Lei, Yu; Kasi, Rajeswari M; Kumar, Challa V

    2015-09-18

    In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, M(W) 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17-20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at -0.279 and -0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 μM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications.

  2. pH- and ionic-strength-induced structural changes in poly(acrylic acid)-lipid-based self-assembled materials.

    SciTech Connect

    Crisci, A.; Hay, D. N. T.; Seifert, S.; Firestone, M. A.

    2009-01-01

    The effect of a polyanion introduced as a lipid conjugate (poly(acrylic acid)- dimyristoyl-sn-glycero-3-phosphoethanolamine, PAA-DMPE) on the structure of a self-assembled, biomembrane mimetic has been evaluated using synchrotron small-angle X-ray scattering (SAXS). At high grafting density (8-11 mol.%), the PAA chains were found to produce significant changes in structure in response to changes in pH and electrolyte composition. At low pH and in the absence of salt (NaCl), the neutral PAA chains adopt a coil conformational state that leads to the formation of a swollen lamellar structure. Upon the addition of salt at low to intermediate pH values, two lamellar phases, a collapsed and an expanded structure, coexist. Finally, when the polymer is fully ionized (at high pH), the extended conformation of the polymer generates a cubic phase. The results of this study contribute to an understanding of how polyelectrolytes may ultimately be harnessed for the preparation of self-assembling materials responsive to external stimuli.

  3. Plasma polymerization of acrylic acid onto polystyrene by cyclonic plasma at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Chang, Yi-Jan; Lin, Chin-Ho; Huang, Chun

    2016-01-01

    The cyclonic atmospheric-pressure plasma is developed for chamberless deposition of poly(acrylic acid) film from argon/acrylic acid mixtures. The photoemission plasma species in atmospheric-pressure plasma polymerization was identified by optical emission spectroscopy (OES). The OES diagnosis data and deposition results indicated that in glow discharge, the CH and C2 species resulted from low-energy electron-impact dissociation that creates deposition species, but the strong CO emission lines are related to nondeposition species. The acrylic acid flow rate is seen as the key factor affecting the film growth. The film surface analysis results indicate that a smooth, continuous, and uniform surface of poly(acrylic acid) films can be formed at a relatively low plasma power input. This study reveals the potential of chamberless film growth at atmospheric pressure for large-area deposition of poly(acrylic acid) films.

  4. Spectral filters based on ethylene/acrylic acid copolymer ionomers

    SciTech Connect

    Riley, M.O.; Walkup, C.M.; Hagen, W.F.; Jessop, E.S.

    1988-09-01

    We are investigating the possibility of utilizing ionomers as inexpensive, easily replaced optical filters for applications in large fusion lasers as well as high average power solid state lasers. To this end we have synthesized a number of other derivatives of the ethylene/acrylic acid (EAA) copolymer system. Specifically, we prepared several ionomers at nominal 3 wt. % metal ion concentration, including Fe(III), Co(II), Ni(II), Cu(II), and Ce(III), by reacting aqueous solutions of metal acetates or nitrates with aqueous ammonia dispersions (1) of EAA as described previously. The products were compression molded into thin optically clear films under the above-described conditions. A gel was formed in a similar reaction with samarium (III) nitrate. Accordingly, the samarium ionomer was synthesized by a melt phase reaction between the EAA resin and the metal nitrate. 6 refs., 2 figs., 2 tabs.

  5. Radiation-induced grafting of acrylic acid onto polyethylene filaments

    NASA Astrophysics Data System (ADS)

    Kaji, K.; Okada, T.; Sakurada, I.

    Radiation-induced grafting of acrylic acid onto high density polyethylene (PE) filaments was carried out in order to raise softening temperature and impart flame retardance and hydrophilic properties. Mutual γ-irradiation method was employed for the grafting in a mixture of acrylic acid (AA), ethylene dichloride and water containing a small amount of ferrous ammonium sulfate. The rate of grafting was very low at room temperature. On the other hand, large percent grafts were obtained when the grafting was performed at an elevated temperature. Activation energy for the initial rate of grafting was found to be 17 {kcal}/{mol} between 20 and 60°C and 10 {kcal}/{mol} between 60 and 80°C. Original PE filament begins to shrink at 70°C, show maximum shrinkage of 50% at 130°C and then breaks off at 136°C. When a 34% AA graft is converted to metallic salt such as sodium and calcium, the graft filament retains its filament form even above 300°C and gives maximum shrinkage of 15%. Burning tests by a wire-netting basket method indicate that graft filaments and its metallic salts do not form melting drops upon burning and are self-extinguishing. Original PE filament shows no moisture absorption, however, that of AA-grafted PE increases with increasing graft percent. The sodium salt of 15% graft shows the same level of moisture regain as cotton. The AA-grafted PE filament and its metallic salts can be dyed with cationic dyes even at 1% graft. Tensile properties of PE filament is impaired neither by grafting nor by conversion to metallic salts.

  6. 40 CFR 721.10389 - Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Styrene, copolymer with acrylic acid... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10389 Styrene, copolymer with acrylic... subject to reporting. (1) The chemical substance identified generically as styrene, copolymer with...

  7. 40 CFR 721.10389 - Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Styrene, copolymer with acrylic acid... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10389 Styrene, copolymer with acrylic... subject to reporting. (1) The chemical substance identified generically as styrene, copolymer with...

  8. 40 CFR 721.10389 - Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Styrene, copolymer with acrylic acid... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10389 Styrene, copolymer with acrylic... subject to reporting. (1) The chemical substance identified generically as styrene, copolymer with...

  9. Synthesis of a proline-modified acrylic acid copolymer in supercritical CO2 for glass-ionomer dental cement applications.

    PubMed

    Moshaverinia, Alireza; Roohpour, Nima; Darr, Jawwad A; Rehman, Ihtesham U

    2009-06-01

    Supercritical (sc-) fluids (such as sc-CO(2)) represent interesting media for the synthesis of polymers in dental and biomedical applications. Sc-CO(2) has several advantages for polymerization reactions in comparison to conventional organic solvents. It has several advantages in comparison to conventional polymerization solvents, such as enhanced kinetics, being less harmful to the environment and simplified solvent removal process. In our previous work, we synthesized poly(acrylic acid-co-itaconic acid-co-N-vinylpyrrolidone) (PAA-IA-NVP) terpolymers in a supercritical CO(2)/methanol mixture for applications in glass-ionomer dental cements. In this study, proline-containing acrylic acid copolymers were synthesized, in a supercritical CO(2) mixture or in water. Subsequently, the synthesized polymers were used in commercially available glass-ionomer cement formulations (Fuji IX commercial GIC). Mechanical strength (compressive strength (CS), diametral tensile strength (DTS) and biaxial flexural strength (BFS)) and handling properties (working and setting time) of the resulting modified cements were evaluated. It was found that the polymerization reaction in an sc-CO(2)/methanol mixture was significantly faster than the corresponding polymerization reaction in water and the purification procedures were simpler for the former. Furthermore, glass-ionomer cement samples made from the terpolymer prepared in sc-CO(2)/methanol exhibited higher CS and DTS and comparable BFS compared to the same polymer synthesized in water. The working properties of glass-ionomer formulations made in sc-CO(2)/methanol were comparable and better than the values of those for polymers synthesized in water. PMID:19269267

  10. Self-healing multilayer polyelectrolyte composite film with chitosan and poly(acrylic acid).

    PubMed

    Zhu, Yanxi; Xuan, Hongyun; Ren, Jiaoyu; Ge, Liqin

    2015-11-21

    If self-healing materials can be prepared via simple technology and methods using nontoxic materials, this would be a great step forward in the creation of environmentally friendly self-healing materials. In this paper, the specific structural parameters of the various hydrogen bonds between chitosan (CS) and polyacrylic acid (PAA) were calculated. Then, multilayer polyelectrolyte films were fabricated with CS and PAA based on layer-by-layer (LbL) self-assembly technology at different pH values. The possible influence of pH on the (CS/PAA) × 30 multilayer polyelectrolyte film was investigated. The results show that the interactions between CS and PAA, swelling capacity, microstructure, wettability, and self-healing ability are all governed by the pH of the CS solution. When the pH value of the CS solution is 3.0, the prepared multilayer polyelectrolyte film (CS3.0/PAA2.8) × 30 has fine-tuned interactions, a network-like structure, good swelling ability, good hydrophilicity, and excellent self-healing ability. This promises to greatly widen the future applications of environmentally friendly materials and bio-materials. PMID:26364567

  11. Chitosan-decorated polystyrene-b-poly(acrylic acid) polymersomes as novel carriers for topical delivery of finasteride.

    PubMed

    Caon, Thiago; Porto, Ledilege Cucco; Granada, Andréa; Tagliari, Monika Piazzon; Silva, Marcos Antonio Segatto; Simões, Cláudia Maria Oliveira; Borsali, Redouane; Soldi, Valdir

    2014-02-14

    In view of the fact that the oral administration of finasteride (FIN) has resulted in various undesirable systemic side effects, the topical application of polystyrene and poly(acrylic acid)-based polymersomes (underexplored system) was investigated. Undecorated PS139-b-PAA17 and PS404-b-PAA63 vesicles (C3 and C7, respectively) or vesicles decorated with chitosan samples of different molecular weight (C3/CS-oligo, C7/CS-oligo, C3/CS-37 and C7/CS-37) were prepared by the co-solvent self-assembly method and characterized by small-angle X-ray scattering,transmission electron microscopy and dynamic light scattering techniques. In vitro release experiments and ex vivo permeation using Franz diffusion cells were carried out (through comparison with hydroethanolic finasteride solution). The ideal system should provide high finasteride retention in the dermis and epidermis while allowing some control of the drug release. The particle size and in vitro release were negatively correlated with the permeation coefficient and skin retention in both the epidermis and dermis. The findings that the longest lag time was obtained for the hydroethanolic drug solution and lowest permeation for the systems able to release the drug faster support the hypothesis that nanostructured systems may be required to enhance the penetration and permeation of the drug. Chitosan-decorated polymersomes interacted more strongly with the skin components than non-decorated samples, probably due to the positive surface charge, which increased the FIN retention and reduced the lag time. C7 polymersomes decorated with chitosan were more appropriate for topical applications (high retention in the dermis and epidermis and controlled drug delivery).

  12. Synthesis and self-assembly of poly(3-hexylthiophene)-block-poly(acrylic acid)

    SciTech Connect

    Li, Zicheng; Ono, Robert J.; Wu, Zong-Quan; Bielawski, Christopher W.

    2011-01-01

    A modular and convenient synthesis of ethynyl end functionalized poly(3-hexylthiophene) in high purity is reported; this material facilitated access to poly(3-hexylthiophene)-block-poly(acrylic acid) which self-assembled into hierarchical structures.

  13. Chemical Analysis and Aqueous Solution Properties of Charged Amphiphilic Block Copolymers PBA-b-PAA Synthesized by MADIX

    SciTech Connect

    Jacquin,M.; Muller, P.; Talingting-Pabalan, R.; Cottet, H.; Berret, J.; Futterer, T.; Theodoly, O.

    2007-01-01

    We have linked the structural and dynamic properties in aqueous solution of amphiphilic charged diblock copolymers poly(butyl acrylate)-b-poly(acrylic acid), PBA-b-PAA, synthesized by controlled radical polymerization, with the physico-chemical characteristics of the samples. Despite product imperfections, the samples self-assemble in melt and aqueous solutions as predicted by monodisperse microphase separation theory. However, the PBA core are abnormally large; the swelling of PBA cores is not due to AA (the Flory parameter ?PBA/PAA, determined at 0.25, means strong segregation), but to h-PBA homopolymers (content determined by liquid chromatography at the point of exclusion and adsorption transition, LC-PEAT). Beside the dominant population of micelles detected by scattering experiments, capillary electrophoresis CE analysis permitted detection of two other populations, one of h-PAA, and the other of free PBA-b-PAA chains, that have very short PBA blocks and never self-assemble. Despite the presence of these free unimers, the self-assembly in solution was found out of equilibrium: the aggregation state is history dependant and no unimer exchange between micelles occurs over months (time-evolution SANS). The high PBA/water interfacial tension, measured at 20 mN/m, prohibits unimer exchange between micelles. PBA-b-PAA solution systems are neither at thermal equilibrium nor completely frozen systems: internal fractionation of individual aggregates can occur.

  14. Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.

    PubMed

    Essawy, Hisham A; Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F

    2016-08-01

    Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications. PMID:27126169

  15. Superabsorbent hydrogels via graft polymerization of acrylic acid from chitosan-cellulose hybrid and their potential in controlled release of soil nutrients.

    PubMed

    Essawy, Hisham A; Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F

    2016-08-01

    Superabsorbent polymers fabricated via grafting polymerization of acrylic acid from chitosan (CTS) yields materials that suffer from poor mechanical strength. Hybridization of chitosan with cellulose (Cell) via chemical bonding using thiourea formaldehyde resin increases the flexibility of the produced hybrid (CTS/Cell). The hybridization process and post graft polymerization of acrylic acid was followed using Fourier transform infrared (FTIR). Also, the obtained structures were homogeneous and exhibited uniform surface as could be shown from imaging with scanning electron microscopy (SEM). Thus, the polymers derived from the grafting of polyacrylic acid from (CTS/Cell) gave rise to much more mechanically robust structures ((CTS/Cell)-g-PAA) that bear wide range of pH response due to presence of chitosan and polyacrylic acid in one homogeneous entity. Additionally, the obtained structures possessed greater water absorbency 390, 39.5g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced retention potential even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high grafting efficiency (GE%), 86.4%, and grafting yield (GY%), 750%. The new superabsorbent polymers proved to be very efficient devices for controlled release of fertilizers into the soil which expands their use in agriculture and horticultural applications.

  16. Radiation grafting of acrylic acid onto polypropylene films

    NASA Astrophysics Data System (ADS)

    Taher, N. H.; Dessouki, A. M.; Khalil, F. H.

    A study has been made for the preparation of membranes by the direct radiation grafting of acrylic acid (AAc) onto polypropylene (PP) films. The appropriate reaction conditions were selected under which the graft polymerization was carried out successfully. The effect of different solvents such as benzene, methanol/water mixture, isopropanol/water mixture, dimethyl formalide and distilled water on the swelling and grafting process of AAc onto PP films was investigated. In this grafting system ammonium ferrous sulphate (Mohr's salt) and ferric chloride were used as inhibitors to minimize the homopolymerization of AAc and the suitable concentration of the inhibitor was found to be 1.0 and 1.5 wt% for Mohr's salt and ferric chloride, respectively. Also, the effect of monomer concentration on the rate of grafting was investigated. The dependence of the grafting rate on monomer concentration was found to be 1.1 order. This grafting system proceeded by diffusion controlled process. Some selected properties of the grafted films such as swelling behavior, gel determination, mechanical and electrical properties were also investigated. It was found that the grafted membranes possess good hydrophilic properties which may make them promising in some practical applications.

  17. Radiation-induced grafting of acrylic acid onto polypropylene film and its biodegradability

    NASA Astrophysics Data System (ADS)

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Chaudhari, C. V.; Dubey, K. A.; Varshney, L.

    2016-06-01

    Polypropylene based commodity polyolefins are widely used in packaging, manufacturing, electrical, pharmaceutical and other applications. The aim of the present work is to study the effect of grafting of acrylic acid on the biodegradability of acrylic acid grafted polypropylene. The effect of different conditions showed that grafting percentage increased with increase in monomer concentration, radiation dose and inhibitor concentration but decreased with increase in radiation dose rate. The maximum grafting of 159.4% could be achieved at optimum conditions. The structure of grafted polypropylene films at different degree of grafting was characterized by EDS, FTIR, TGA, DSC, SEM and XRD. EDS studies showed that the increase in acrylic acid grafting percentage increased the hydrophilicity of the grafted films. FTIR studies indicated the presence of acrylic acid on the surface of polypropylene film. TGA studies revealed that thermal stability decreased with increase in grafting percentage. DSC studies showed that melting temperature and crystallinity of the grafted polypropylene films lower than polypropylene film. SEM studies indicated that increase in acrylic acid grafting percentage increased the wrinkles in the grafted films. The maximum biodegradability could be achieved to 6.85% for 90.5% grafting. This suggested that microorganisms present in the compost could biodegrade acrylic acid grafted polypropylene.

  18. Surfactant mediated synthesis of poly(acrylic acid) grafted xanthan gum and its efficient role in adsorption of soluble inorganic mercury from water.

    PubMed

    Pal, Abhijit; Majumder, Kunal; Bandyopadhyay, Abhijit

    2016-11-01

    Noble copolymers from xanthan gum (XG) and poly(acrylic acid) (PAA) were synthesised through surfactant mediated graft copolymerization. The copolymers were applied as a biosorbent for inorganic Hg(II) at higher concentration level (300ppm). The copolymers were characterized using different analytical techniques which showed, the grafting principally occurred across the amorphous region of XG. Measurement of zeta potential and hydrodynamic size indicated, the copolymers were strong polyanion and possessed greater hydrodynamic size (almost in all cases) than XG, despite a strong molecular degradation that took place simultaneously during grafting. In the dispersed form, all grades of the copolymer displayed higher adsorption capability than XG, however, the grade with maximum grafting produced the highest efficiency (68.03%). Manipulation produced further improvement in efficiency to 72.17% with the same copolymer after 75min at a pH of 5.0. The allowable biosorbent dose, however, was 1000ppm as determined from the experimental evidences. PMID:27516248

  19. Reusable nanocomposite of CoFe2O4/chitosan-graft-poly(acrylic acid) for removal of Ni(II) from aqueous solution

    NASA Astrophysics Data System (ADS)

    Nguyen, Van Cuong; Huynh, Thi Kim Ngoc

    2014-06-01

    In this paper, CoFe2O4/chitosan-graft-poly(acrylic acid) (CoFe2O4/CS-graft-PAA) nanocomposites were prepared successfully by coprecipitation of the compounds in alkaline solution and were used for removal of nickel (II) ions from aqueous solution. The sorption rate was affected significantly by the initial concentration of the solution, sorbent amount, and pH value of the solution. Batch experiments were conducted to investigate the adsorption capacity under different initial concentration (ranging from 25 to 150 mg L-1), solution pH (4.1, 5.3, 6.4 and 7.6), and contact time. These nanocomposites can be recycled conveniently from water with the assistance of an external magnet because of their exceptional properties. The prepared nanocomposites were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), x-ray powder diffraction (XRD), and thermogravimetric analysis (TGA).

  20. High cycling stability of anodes for lithium-ion batteries based on Fe3O4 nanoparticles and poly(acrylic acid) binder

    NASA Astrophysics Data System (ADS)

    Maroni, F.; Gabrielli, S.; Palmieri, A.; Marcantoni, E.; Croce, F.; Nobili, F.

    2016-11-01

    Fe3O4 nanoparticles synthesized by a base catalyzed method are tested as anode material for Li-ion batteries. The pristine nanoparticles are morphologically characterized showing an average size of 11 nm. Electrodes are prepared using high-molecular weight Poly (acrylic acid) as improved binder and ethanol as low cost and environmentally friendly solvent. The evaluation of electrochemical properties shows high specific capacity values of 857 mA hg-1 after 200 cycles at a specific current of 462 mAg-1, as well as an excellent rate capability with specific current values up to 18480 mAg-1. To the best of our knowledge, this is the first report of Fe3O4 nanoparticles cycling with PAA as binder.

  1. Amorphous polymeric anode materials from poly(acrylic acid) and tin(II) oxide for lithium ion batteries

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Hiroyuki; Nakanishi, Shinji; Iba, Hideki; Itoh, Takahito

    2015-02-01

    The reaction of poly(acrylic acid) (PAA) and tin oxide (II) (SnO) provides an amorphous product (PSnA), which was found to be a promising precursor of an anode material for lithium ion batteries. The anode electrode composed of PSnA as the active material and polyimide as the binder showed a better cycling performance than the anode electrode using SnO as the active material. It is considered that the organic polymer chain present in PSnA might act as a buffer to the volume change in the active material during the charge-discharge cycles. The X-ray diffraction (XRD) results of the electrode after delithiation revealed that nano-sized cubic tin (α-Sn) and tetragonal tin (β-Sn) particles are formed in the active material. Therefore, it is concluded that these nano-sized tin particles in the polymer matrix were effective for the storage and release of Li ions.

  2. Radiation modification of water absorption of cassava starch by acrylic acid/acrylamide

    NASA Astrophysics Data System (ADS)

    Kiatkamjornwong, Suda; Chomsaksakul, Wararuk; Sonsuk, Manit

    2000-10-01

    Graft copolymerizations of acrylamide and/or acrylic acid onto cassava starch by a simultaneous irradiation technique using gamma-rays as the initiator were studied with regard to various parameters of importance: the monomer-to-cassava starch ratio, total dose (kGy), dose rate (kGy h -1), acrylamide-to-acrylic acid ratio, and the addition of nitric acid and maleic acid as the additives. Grafting parameters were determined in relation to the water absorption of the saponified graft copolymer. The water absorption of the saponified graft copolymer in salt and buffer solutions of different ionic strengths was also measured, from which the superabsorbent properties are found to be pH sensitive. The starch graft copolymers of acrylamide and acrylic acid give higher water absorption than the starch graft copolymers of either acrylamide or acrylic acid alone. The porosity of the saponified starch graft copolymers prepared by the acrylamide/acrylic acid ratios of 70:30 and 50:50 was much higher than the porosity of copolymers in terms of fine networks. Ionic strength and multi-oxidation states of the saline and buffer solutions markedly decreased the water absorption of the saponified cassava starch grafted superabsorbent polymers.

  3. Conversion of (Meth)acrylic acids to methane granular sludge: Initiation by specific anerobic microflora

    SciTech Connect

    Shtarkman, N.B.; Obraztova, A.Y.; Laurinavichyus, K.S.; Galushko, A.S.; Akimenko, V.K.

    1995-03-01

    The role of a specific anaerobic microflora in the initiation of degradation of (meth)acrylic acids to methane by granular sludge from a UASB reactor was investigated. Associations of anaerobic bacteria isolated from the anaerobic sludge, which was used for a long time for treatment of wastewater from (meth)acrylate production, were able to realize the initial stage of (meth)acrylic acid decomposition, i.e., a conversion of acrylic and methacrylic acids to propionic and isobutyric acids, respectively. When added to granules, these association played a role of an {open_quotes}initiator{close_quotes} of the degradation process, which was then continued by the granular sludge microflora utilizing propionate and isobutyrate. Some characteristics of the granules adapted to propionate or isobutyrate are presented. The rates of propionate and isobutyrate consumption by adapted granules is, respectively, 21 and 53 times higher than the values obtained for nonadapted granules. A combined use of {open_quotes}initiating{close_quotes} bacteria and adapted granules provided degradation of (meth)acrylic acids with a maximum methane yield. The possibility is discussed of employing the granules, which are adapted to short-chain fatty acids, and the {open_quotes}initiating{close_quotes} bacteria, which accomplish the initial steps of the organic material decomposition to lower fatty acids, for the conversion of various chemical compounds to methane. 10 refs., 3 figs., 2 tabs.

  4. Hindered Diffusion of Oligosaccharides in High Strength Poly(ethylene glycol)/Poly(acrylic acid) Interpenetrating Network Hydrogels: Hydrodynamic Versus Obstruction Models

    PubMed Central

    Waters, Dale J.; Frank, Curtis W.

    2010-01-01

    Diffusion coefficients of small oligosaccharides within high strength poly(ethylene glycol)/poly(acrylic acid) interpenetrating network (PEG/PAA IPN) hydrogels were measured by diffusion through hydrogel slabs. The ability of hindered diffusion models previously presented in the literature to fit the experimental data is examined. A model based solely on effects due to hydrodynamics is compared to a model based solely on solute obstruction. To examine the effect of polymer volume fraction on the observed diffusion coefficients, the equilibrium volume fraction of polymer in PEG/PAA IPNs was systematically varied by changing the initial PEG polymer concentration in hydrogel precursor solutions from 20 to 50 wt./wt.%. To examine the effect of solute radius on the observed diffusion coefficients, solute radii were varied from 3.3 to 5.1 Å by measuring diffusion coefficients of glucose, a monosaccharide; maltose, a disaccharide; and maltotriose, a trisaccharide. Both the hydrodynamic and obstruction models rely on scaling relationships to predict diffusion coefficients. The proper scaling relationship for each of the hindered diffusion models is evaluated based on fits to experimental data. The scaling relationship employed is found to have a greater significance for the hydrodynamic model than the obstruction model. Regardless of the scaling relationship employed, the obstruction model provides a better fit to our experimental data than the hydrodynamic model. PMID:20514136

  5. High strength of physical hydrogels based on poly(acrylic acid)-g-poly(ethylene glycol) methyl ether: role of chain architecture on hydrogel properties.

    PubMed

    Yang, Jun; Gong, Cheng; Shi, Fu-Kuan; Xie, Xu-Ming

    2012-10-01

    This investigation was to study the connections between polymer branch architecture of physical hydrogels and their properties. The bottle-brush-like polymer chains of poly(acrylic acid)-g-poly(ethylene glycol) methyl ether (PAA-g-mPEG) with PAA as backbones and mPEG as branch architecture were synthesized and in situ grafted from silica nanoparticles (SNs) to construct hydrogels cross-linked networks in aqueous solutions. The structural variables to be discussed included molecular weight and molar ratio of branch chains, and new aspects of the formation mechanism of physical hydrogels with branch structure in the absence of organic cross-links were present. The results indicated that the differences of polymer chain architecture could be distinguished via their different interactions that are present by gelation process and mature gel properties, such as gel strength and swelling ratio. The gelation occurred at the critical polymer concentration and molecular weight, respectively, and the inorganic/organic (SNs/PAA-g-mPEG) nanoparticles began to entangle and construct the cross-linking networks afterward. The gel-to-sol transition temperature (T(g-s)) and radii of SNs that were encapsulated by polymer chains as a function of time for chains' disentanglement were monitored according to the observation of the dissolution process, and the molecular weight between two consecutive entanglements (M(e)) was calculated thereafter. This study showed that the introduction of branch chain onto the linear backbone significantly promoted the chain interactions and increased entanglement density, which contributed to the hydrogels' network integrity and rigidity, thus illustrating greater elongation at break and tensile strength than the hydrogels formulated with linear polymer chains.

  6. Electrically conducting silver/guar gum/poly(acrylic acid) nanocomposite.

    PubMed

    Abdel-Halim, E S; Al-Deyab, Salem S

    2014-08-01

    This article describes the synthesis of an electrically conducting silver/guar gum/poly(acrylic acid) nanocomposite hydrogel. The synthesis process started with grafting acrylic acid monomers onto the natural polymer guar gum by the use of ammonium persulphate as a free radical initiator in acid medium. Guar gum/poly(acrylic acid) graft copolymer was separated from the polymerization medium, purified and subjected to crosslinking treatment, using alkaline epichlorohydrin as a crosslinking agent. Silver nitrate solution was added during the crosslinking treatment in varying concentrations, that the reaction conditions affect crosslinking of guar gum/poly(acrylic acid) graft copolymer to a hydrogel, as well as reduction of silver nitrate to silver nanoparticles, giving rise to the formation of silver/guar gum/poly(acrylic acid) nanocomposite. Factors affecting the grafting reaction as well as those affecting the crosslinking/reduction treatment were optimized. The so synthesized nanocomposite hydrogel samples were fully characterized, regarding their contents of silver nanoparticles and swelling ratio. The electrical conductivity of the nanocomposite hydrogel was studied and it was found to be affected by the swelling ratio of the hydrogel as well as its content of silver nanoparticles. PMID:24928058

  7. Electrically conducting silver/guar gum/poly(acrylic acid) nanocomposite.

    PubMed

    Abdel-Halim, E S; Al-Deyab, Salem S

    2014-08-01

    This article describes the synthesis of an electrically conducting silver/guar gum/poly(acrylic acid) nanocomposite hydrogel. The synthesis process started with grafting acrylic acid monomers onto the natural polymer guar gum by the use of ammonium persulphate as a free radical initiator in acid medium. Guar gum/poly(acrylic acid) graft copolymer was separated from the polymerization medium, purified and subjected to crosslinking treatment, using alkaline epichlorohydrin as a crosslinking agent. Silver nitrate solution was added during the crosslinking treatment in varying concentrations, that the reaction conditions affect crosslinking of guar gum/poly(acrylic acid) graft copolymer to a hydrogel, as well as reduction of silver nitrate to silver nanoparticles, giving rise to the formation of silver/guar gum/poly(acrylic acid) nanocomposite. Factors affecting the grafting reaction as well as those affecting the crosslinking/reduction treatment were optimized. The so synthesized nanocomposite hydrogel samples were fully characterized, regarding their contents of silver nanoparticles and swelling ratio. The electrical conductivity of the nanocomposite hydrogel was studied and it was found to be affected by the swelling ratio of the hydrogel as well as its content of silver nanoparticles.

  8. Synthesis of a novel acrylated abietic acid-g-bacterial cellulose hydrogel by gamma irradiation.

    PubMed

    Abeer, Muhammad Mustafa; Amin, Mohd Cairul Iqbal Mohd; Lazim, Azwan Mat; Pandey, Manisha; Martin, Claire

    2014-09-22

    Acrylated abietic acid (acrylated AbA) and acrylated abietic acid-grafted bacterial cellulose pH sensitive hydrogel (acrylated AbA-g-BC) were prepared by a one-pot synthesis. The successful dimerization of acrylic acid (AA) and abietic acid (AbA) and grafting of the dimer onto bacterial cellulose (BC) was confirmed by 13C solid state NMR as well as FT-IR. X-ray diffraction analysis showed characteristic peaks for AbA and BC; further, there was no effect of increasing amorphous AA content on the overall crystallinity of the hydrogel. Differential scanning calorimetry revealed a glass transition temperature of 80°C. Gel fraction and swelling studies gave insight into the features of the hydrogel, suggesting that it was suitable for future applications such as drug delivery. Scanning electron microscopy observations showed an interesting interpenetrating network within the walls of hydrogel samples with the lowest levels of AA and gamma radiation doses. Cell viability test revealed that the synthesized hydrogel is safe for future use in biomedical applications.

  9. Evaluation of liquid-liquid extraction process for separating acrylic acid produced from renewable sugars.

    PubMed

    Alvarez, M E T; Moraes, E B; Machado, A B; Maciel Filho, R; Wolf-Maciel, M R

    2007-04-01

    In this article, the separation and the purification of the acrylic acid produced from renewable sugars were studied using the liquid-liquid extraction process. Nonrandom two-liquids and universal quasi-chemical models and the prediction method universal quasi-chemical functional activity coefficients were used for generating liquid-liquid equilibrium diagrams for systems made up of acrylic acid, water, and solvents (diisopropyl ether, isopropyl acetate, 2-ethyl hexanol, and methyl isobutyl ketone) and the results were compared with available liquid-liquid equilibrium experimental data. Aspen Plus (Aspen Technology, Inc., version 2004.1) software was used for equilibrium and process calculations. High concentration of acrylic acid was obtained in this article using diisopropyl ether as solvent.

  10. Radiation synthesis of superabsorbent poly(acrylic acid)-carrageenan hydrogels

    NASA Astrophysics Data System (ADS)

    Francis, Sanju; Kumar, Manmohan; Varshney, Lalit

    2004-04-01

    A series of superabsorbent hydrogels were prepared from carrageenan and partially neutralized acrylic acid by gamma irradiation at room temperature. The gel fraction, swelling kinetics and the equilibrium degree of swelling (EDS) of the hydrogels were studied. It was found that the incorporation of even 1% carrageenan (sodium salt) increases the EDS of the hydrogels from ˜320 to ˜800 g/g. Thermal analysis were carried out to determine the amount of free water and bound water in the hydrogels. Under optimum conditions, poly(acrylic acid)-carrageenan hydrogels with high gel fraction (˜80%) and very high EDS (˜800 g/g) were prepared gamma radiolytically from aqueous solution containing 15% partially neutralized acrylic acid and 1-5% carrageenan. The hydrogels were also found to be sensitive to the pH and the ionic strength of the medium.

  11. Radiation grafting of acrylic and methacrylic acid to cellulose fibers to impart high water sorbency

    SciTech Connect

    Zahran, A.H.; Williams, J.L.; Stannett, V.T.

    1980-04-01

    Acrylic and methacrylic acids have been directly grafted to rayon and cotton using the preirradiation technique with /sup 60/ Co gamma rays. The rate of grafting increased with increasing temperature and monomer concentration, as did the final degree of grafting. The amount and rate of grafting also increased with the total irradiation dose but tended to level off at higher doses, in agreement with the leveling off of the radical content reported previously. Methacrylic acid grafted more and faster than acrylic acid to both rayon and cotton. Methacrylic acid grafted more with rayon than cotton, but acrylic acid gave somewhat similar yields with both fibers. The water abosrbency of the grafted fibers depended strongly on their posttreatment. Decrystallizing with 70% zinc chloride or with hot sodium hydroxidy developed supersorbency. The two treatments in succession, respectively, gave the highest values. Metacrylic acid brought about less sorbency than the corrsponding acrylic acid grafts. Useful levels of grafting and supersorbency could be readily and practically achieved by the methods described.

  12. Poly(acrylic acid) to induce competitive crystallization of a theophylline/oxalic acid cocrystal and a theophylline polymorph

    NASA Astrophysics Data System (ADS)

    Jang, Jisun; Kim, Il Won

    2016-01-01

    Polymeric additives to induce competitive crystallization of pharmaceutical compounds were explored. A cocrystal of theophylline and oxalic acid was used as a model system, and poly(acrylic acid), poly(caprolactone), and poly(ethylene glycol) were the additives. The cocrystal formation was selectively hindered with addition of poly(acrylic acid). First the size of the cocrystals were reduced, and eventually the cocrystallization was inhibited to generate neat theophylline crystals. The theophylline crystals were of a distinctively different crystal structure from known polymorphs, based on powder X-ray diffraction. They were also obtained in nanoscale size, when millimeter-scale crystals formed without poly(acrylic acid). Polymeric additives that could form specific interactions with crystallizing compounds seem to be useful tools for the phase and size control of pharmaceutical crystals.

  13. Stable plasma-deposited acrylic acid surfaces for cell culture applications.

    PubMed

    Detomaso, Loredana; Gristina, Roberto; Senesi, Giorgio S; d'Agostino, Riccardo; Favia, Pietro

    2005-06-01

    Continuous and modulated glow discharges were used to deposit thin films from acrylic acid vapors. Different deposition regimes were investigated, and their effect on chemical composition, morphology and homogeneity of the coatings, as well as on their stability in water and resistance to sterilization. Stable films were utilized in cell adhesion experiments with human fibroblasts. PMID:15626431

  14. Continuous process of preparation of n-butyl(meth)acrylate by esterification of (meth)acrylic acid by butanol on thermostable sulfo-cation exchanger

    SciTech Connect

    Zheleznaya, L.L.; Karakhanov, R.A.; Lunin, A.F.; Magadov, R.S.; Meshcheryakov, S.V.; Mkrtychan, V.R.; Fomin, V.A.

    1987-11-10

    The authors propose an effective thermostable sulfo-cation exchanger based on polymers with a system of conjugated bonds, sulfopolyphenylene ketone (SPP) differing from the known cation exchangers by the high thermostability (up to 250/sup 0/C), and also having the effect of the stabilization of the double bond in unsaturated monomers. The combination of inhibiting and cation exchange properties makes it also possible to use these sulfo-cation exchangers in the processes of esterification of (meth)acrylic acids by alcohols without addition of special inhibitors. The SPP catalyst was tested in esterification processes of acrylic an methacrylic acid by butanol at a pilot plant.

  15. Radioluminescence of polyester resin modified with acrylic acid and its salts

    NASA Astrophysics Data System (ADS)

    Szalińska, H.; Wypych, M.; Pietrzak, M.; Szadkowska-Nicze, M.

    Polimal-109 polyester resin and its compounds containing acrylic acid and its salts such as: sodium, potassium, magnesium, calcium, barium, iron, cobalt, copper and manganese acrylates were studied by the radioluminescence method, including isothermal luminescence (ITL) at a radiation temperature of 77 K, thermoluminescence (RTL) and spectral distributions of isothermal luminescence. Measurements of optical absorption at 77 K before and after irradiation of the investigated samples were also carried out. The results obtained have shown that metal ions play a significant part in the processes taking place in the polyester matrix under the influence of γ 60Co radiation.

  16. Pre-irradiation induced emulsion co-graft polymerization of acrylonitrile and acrylic acid onto a polyethylene nonwoven fabric

    NASA Astrophysics Data System (ADS)

    Liu, Hanzhou; Yu, Ming; Ma, Hongjuan; Wang, Ziqiang; Li, Linfan; Li, Jingye

    2014-01-01

    A pre-irradiation induced emulsion co-graft polymerization method was used to introduce acrylonitrile and acrylic acid onto a PE nonwoven fabric. The use of acrylic acid is meant to improve the hydrophilicity of the modified fabric. The kinetics of co-graft polymerization were studied. The existence of polyacrylonitrile (PAN) and poly(acrylic acid) (PAAc) graft chains was proven by Fourier transform infrared spectroscopy (FTIR) analysis. The existence of the nitrile groups in the graft chains indicates that they are ready for further amidoximation and adsorption of heavy metal ions.

  17. Dehydration of lactic acid to acrylic acid over lanthanum phosphate catalysts: the role of Lewis acid sites.

    PubMed

    Guo, Zhen; Theng, De Sheng; Tang, Karen Yuanting; Zhang, Lili; Huang, Lin; Borgna, Armando; Wang, Chuan

    2016-09-14

    Lanthanum phosphate (LaP) nano-rods were synthesized using n-butylamine as a shape-directing agent (SDA). The resulting catalysts were applied in the dehydration of lactic acid to acrylic acid. Aiming to understand the nature of the active sites, the chemical and physical properties of LaP materials were studied using a variety of characterization techniques. This study showed that the SDA not only affected the porosity of the LaP materials but also modified the acid-base properties. Clearly, the modification of the acid-base properties played a more critical role in determining the catalytic performance than porosity. An optimized catalytic performance was obtained on the LaP catalyst with a higher concentration of Lewis acid sites. Basic sites showed negative effects on the stability of the catalysts. Good stability was achieved when the catalyst was prepared using the appropriate SDA/La ratio. PMID:27514871

  18. Dehydration of lactic acid to acrylic acid over lanthanum phosphate catalysts: the role of Lewis acid sites.

    PubMed

    Guo, Zhen; Theng, De Sheng; Tang, Karen Yuanting; Zhang, Lili; Huang, Lin; Borgna, Armando; Wang, Chuan

    2016-09-14

    Lanthanum phosphate (LaP) nano-rods were synthesized using n-butylamine as a shape-directing agent (SDA). The resulting catalysts were applied in the dehydration of lactic acid to acrylic acid. Aiming to understand the nature of the active sites, the chemical and physical properties of LaP materials were studied using a variety of characterization techniques. This study showed that the SDA not only affected the porosity of the LaP materials but also modified the acid-base properties. Clearly, the modification of the acid-base properties played a more critical role in determining the catalytic performance than porosity. An optimized catalytic performance was obtained on the LaP catalyst with a higher concentration of Lewis acid sites. Basic sites showed negative effects on the stability of the catalysts. Good stability was achieved when the catalyst was prepared using the appropriate SDA/La ratio.

  19. Waveguide CP-FTMW and millimeter wave spectra of s-cis- and s-trans-acrylic acid

    NASA Astrophysics Data System (ADS)

    Alonso, E. R.; Kolesniková, L.; Peña, I.; Shipman, S. T.; Tercero, B.; Cernicharo, J.; Alonso, J. L.

    2015-10-01

    The millimeter wave spectrum of acrylic acid (CH2dbnd CHsbnd COOH), the simplest unsaturated carboxylic acid, was measured and analyzed from 130 to 360 GHz. Additional measurements from 18 to 26.5 GHz were also made using a waveguide CP-FTMW spectrometer. More than 4000 rotational lines were assigned to s-cis- and s-trans-acrylic acid in their ground vibrational states leading to precise determination of rotational, quartic and first complete set of sextic centrifugal distortion constants. New laboratory data of acrylic acid were then used to search for its spectral features in Orion KL, Sgr B2, and W51 molecular clouds. An upper limit to the column density of acrylic acid in Orion KL is provided.

  20. Superabsorbent biphasic system based on poly(lactic acid) and poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Sartore, Luciana; Pandini, Stefano; Baldi, Francesco; Bignotti, Fabio

    2016-05-01

    In this research work, biocomposites based on crosslinked particles of poly(acrylic acid), commonly used as superabsorbent polymer (SAP), and poly-L-lactic acid (PLLA) were developed to elucidate the role of the filler (i.e., polymeric crosslinked particles) on the overall physico-mechanical behavior and to obtain superabsorbent thermoplastic products. Samples prepared by melt-blending of components in different ratios showed a biphasic system with a regular distribution of particles, with diameter ranging from 5 to 10 μm, within the PLLA polymeric matrix. The polymeric biphasic system, coded PLASA i.e. superabsorbent poly(lactic acid), showed excellent swelling properties, demonstrating that cross-linked particles retain their superabsorbent ability, as in their free counterparts, even if distributed in a thermoplastic polymeric matrix. The thermal characteristics of the biocomposites evidence enhanced thermal stability in comparison with neat PLLA and also mechanical properties are markedly modified by addition of crosslinked particles which induce regular stiffening effect. Furthermore, in aqueous environments the particles swell and are leached from PLLA matrix generating very high porosity. These new open-pore PLLA foams, produced in absence of organic solvents and chemical foaming agents, with good physico-mechanical properties appear very promising for several applications, for instance in tissue engineering for scaffold production.

  1. Hierarchically organized architecture of potassium hydrogen phthalate and poly(acrylic acid): toward a general strategy for biomimetic crystal design.

    PubMed

    Oaki, Yuya; Imai, Hiroaki

    2005-12-28

    A hierarchically organized architecture in multiple scales was generated from potassium hydrogen phthalate crystals and poly(acrylic acid) based on our novel biomimetic approach with an exquisite association of polymers on crystallization. PMID:16333511

  2. Crystallization and preliminary X-ray diffraction studies of the transcriptional repressor PaaX, the main regulator of the phenylacetic acid degradation pathway in Escherichia coli W

    PubMed Central

    Rojas-Altuve, Alzoray; Carrasco-López, César; Hernández-Rocamora, Víctor M.; Sanz, Jesús M.; Hermoso, Juan A.

    2011-01-01

    PaaX is the main regulator of the phenylacetic acid aerobic degradation pathway in bacteria and acts as a transcriptional repressor in the absence of its inducer phenylacetyl-coenzyme A. The natural presence and the recent accumulation of a variety of highly toxic aromatic compounds owing to human pollution has created considerable interest in the study of degradation pathways in bacteria, the most important microorganisms capable of recycling these compounds, in order to design and apply novel bioremediation strategies. PaaX from Escherichia coli W was cloned, overexpressed, purified and crystallized using the sitting-drop vapour-diffusion method at 291 K. Crystals grew from a mixture of 0.9 M Li2SO4 and 0.5 M sodium citrate pH 5.8. These crystals, which belonged to the monoclinic space group C2 with unit-cell parameters a = 167.88, b = 106.23, c = 85.87 Å, β = 108.33°, allowed the collection of an X-ray data set to 2.3 Å resolution. PMID:22102047

  3. Ultrafine metal particles immobilized on styrene/acrylic acid copolymer particles

    SciTech Connect

    Tamai, Hisashi; Hamamoto, Shiro; Nishiyama, Fumitaka; Yasuda, Hajime

    1995-04-01

    Ultrafine metal particles immobilized on styrene/acrylic acid copolymer fine particles were produced by reducing the copolymer particles-metal ion complexes or refluxing an ethanol solution of metal ions in the presence of copolymer particles. The size of metal particles formed by reduction of the complex is smaller than that by reflux of the metal ion solution and depends on the amount of metal ions immobilized.

  4. Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocomposites.

    PubMed

    Wan, Sijie; Hu, Han; Peng, Jingsong; Li, Yuchen; Fan, Yuzun; Jiang, Lei; Cheng, Qunfeng

    2016-03-14

    Inspired by the relationship between interface interactions and the high performance mechanical properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepared via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, respectively. In addition, the effect of environmental relative humidity on the mechanical properties of bioinspired nanocomposites is also investigated, and is consistent with previous theoretical predictions. Moreover, this nacre-inspired nanocomposite also displays high electrical conductivity of 108.9 S cm(-1). These excellent physical properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future. PMID:26895081

  5. Nacre-inspired integrated strong and tough reduced graphene oxide-poly(acrylic acid) nanocomposites

    NASA Astrophysics Data System (ADS)

    Wan, Sijie; Hu, Han; Peng, Jingsong; Li, Yuchen; Fan, Yuzun; Jiang, Lei; Cheng, Qunfeng

    2016-03-01

    Inspired by the relationship between interface interactions and the high performance mechanical properties of nacre, a strong and tough nacre-inspired nanocomposite was demonstrated based on graphene oxide (GO) and polyacrylic acid (PAA) prepared via a vacuum-assisted filtration self-assembly process. The abundant hydrogen bonding between GO and PAA results in both high strength and toughness of the bioinspired nanocomposites, which are 2 and 3.3 times higher than that of pure reduced GO film, respectively. In addition, the effect of environmental relative humidity on the mechanical properties of bioinspired nanocomposites is also investigated, and is consistent with previous theoretical predictions. Moreover, this nacre-inspired nanocomposite also displays high electrical conductivity of 108.9 S cm-1. These excellent physical properties allow this type of nacre-inspired nanocomposite to be used in many applications, such as flexible electrodes, aerospace applications, and artificial muscles etc. This nacre-inspired strategy also opens an avenue for constructing integrated high performance graphene-based nanocomposites in the near future.

  6. Adsorption of methyl violet in aqueous solutions by poly(acrylamide-co-acrylic acid) hydrogels

    NASA Astrophysics Data System (ADS)

    Şolpan, D.; Duran, S.; Saraydin, D.; Güven, O.

    2003-02-01

    In this study, Acrylamide(AAm)/Acrylic Acid(AAc) monomer mixtures which contain different quantities of acrylic acid have been irradiated to form hydrogels with γ-radiation. Acrylamide/Acrylic Acid (AAm/AAc) monomer mixtures which contain 15%, 20%, 30% AAm and irradiated with 8.0 kGy were used for swelling and diffusion studies in water and solutions of methyl violet. Diffusions of water and methyl violet within the hydrogels were found to be non-Fickian in character. In experiments on the adsorption of methyl violet, Type-S adsorption was found. Poly(AAm-co-AAc) hydrogel adsorbed methyl violet, while poly(AAm) hydrogel did not adsorb any dye. (Δ H) Heat of adsorption, (Δ G) Free energy of adsorption, (Δ S) Entropy of adsorption were calculated. These results show that poly(AAm-co-AAc) hydrogels can be used as a sorbent for water pollutants such as dyes and treatment of these organic contaminants from wastewater.

  7. Preparation and characterization of poly(acrylic acid)-hydroxyethyl cellulose graft copolymer.

    PubMed

    Abdel-Halim, E S

    2012-10-01

    Poly(acrylic acid) hydroxyethyl cellulose [poly(AA)-HEC] graft copolymer was prepared by polymerizing acrylic acid (AA) with hydroxyethyl cellulose (HEC) using potassium bromate/thiourea dioxide (KBrO(3)/TUD) as redox initiation system. The polymerization reaction was carried out under a variety of conditions including concentrations of AA, KBrO(3) and TUD, material to liquor ratio and polymerization temperature. The polymerization reaction was monitored by withdrawing samples from the reaction medium and measuring the total conversion. The rheological properties of the poly(AA)-HEC graft copolymer were investigated. The total conversion and rheological properties of the graft copolymer depended on the ratio of KBrO(3) to TUD and on acrylic acid concentration as well as temperature and material to liquor ratio. Optimum conditions of the graft copolymer preparation were 30 mmol KBrO(3) and 30 mmol TUD/100g HEC, 100% AA (based on weight of HEC), duration 2h at temperature 50 °C using a material to liquor ratio of 1:10. PMID:22840022

  8. Thermal preparation of chitosan-acrylic acid superabsorbent: optimization, characteristic and water absorbency.

    PubMed

    Ge, Huacai; Wang, Senkang

    2014-11-26

    Chitosan-acrylic acid superabsorbent polymer was successfully prepared by the thermal reaction without using initiator and crosslinker in air. The effects of some reaction variables on the water absorbency of this polymer were investigated by orthogonal tests, and the optimal conditions were described. The influences of temperature, time, ratio of the reactants and neutralization degree of acrylic acid on the reaction were further studied. These polymers were also prepared in nitrogen atmosphere and by using a radical initiator and compared against thermal reaction obtained polymers. The structures of the polymers were characterized by FT-IR, TGA, XRD, (13)C NMR and elemental analyses. The results showed that the thermal reaction product of acrylic acid with chitosan might form N-carboxyethyl grafted and amide-linked polymer and this product could absorb water 644 times its own dry weight. The possible mechanism for the thermal reaction was further suggested. The purpose of this research was to explore the friendly synthesized method of the superabsorbent. PMID:25256488

  9. Pluronic-poly (acrylic acid)-cysteine/Pluronic L121 mixed micelles improve the oral bioavailability of paclitaxel.

    PubMed

    Zhao, Yanli; Li, Yanli; Ge, Jianjun; Li, Na; Li, Ling-Bing

    2014-11-01

    The aim of the study is to synthesize a thiolated Pluronic copolymer, Pluronic-poly (acrylic acid)-cysteine copolymer, to construct a mixed micelle system with the Pluronic-poly (acrylic acid)-cysteine copolymer and Pluronic L121 (PL121) and to evaluate the potential of these mixed micelles as an oral drug delivery system for paclitaxel. Compared with Pluronic-poly (acrylic acid)-cysteine micelles, drug-loading capacity of Pluronic-poly (acrylic acid)-cysteine/PL121 mixed micelles was increased from 0.4 to 2.87%. In vitro release test indicated that Pluronic-poly (acrylic acid)-cysteine/PL121 mixed micelles exhibited a pH sensitivity. The permeability of drug-loaded micelles in the intestinal tract was studied with an in situ perfusion method in rats. The presence of verapamil and Pluronic both improved the intestinal permeability of paclitaxel, which further certified the inhibition effect of thiolated Pluronic on P-gp. In pharmacokinetic study, the area under the plasma concentration-time curve (AUC0→∞) of paclitaxel-loaded mixed micelles was four times greater than that of the paclitaxel solution (p < 0.05). In general, Pluronic-poly (acrylic acid)-cysteine/PL121 micelles were proven to be a potential oral drug delivery system for paclitaxel.

  10. FT-IR and FT-Raman studies of cross-linking processes with Ca(2+) ions, glutaraldehyde and microwave radiation for polymer composition of poly(acrylic acid)/sodium salt of carboxymethyl starch--part I.

    PubMed

    Grabowska, Beata; Sitarz, Maciej; Olejnik, Ewa; Kaczmarska, Karolina

    2015-01-25

    FT-IR and FT-Raman spectroscopic methods allowed to identify the cross-linking process of the aqueous composition of poly(acrylic acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) applied as a binder for moulding sands. The cross-linking was performed by chemical methods by introducing cross-linking substances with Ca(2+) ions or glutaraldehyde and by physical way, applying the microwave radiation. It was found that Ca(2+) ions cause formation of cross-linking ionic bonds within carboxyl and carboxylate groups. Glutaraldehyde generates formation of cross-linking bonds with hemiacetal and acetal structures. Whereas in the microwave radiation field, due to dehydration, lattices are formed by anhydride bonds.

  11. FT-IR and FT-Raman studies of cross-linking processes with Ca2+ ions, glutaraldehyde and microwave radiation for polymer composition of poly(acrylic acid)/sodium salt of carboxymethyl starch - Part I

    NASA Astrophysics Data System (ADS)

    Grabowska, Beata; Sitarz, Maciej; Olejnik, Ewa; Kaczmarska, Karolina

    2015-01-01

    FT-IR and FT-Raman spectroscopic methods allowed to identify the cross-linking process of the aqueous composition of poly(acrylic acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) applied as a binder for moulding sands. The cross-linking was performed by chemical methods by introducing cross-linking substances with Ca2+ ions or glutaraldehyde and by physical way, applying the microwave radiation. It was found that Ca2+ ions cause formation of cross-linking ionic bonds within carboxyl and carboxylate groups. Glutaraldehyde generates formation of cross-linking bonds with hemiacetal and acetal structures. Whereas in the microwave radiation field, due to dehydration, lattices are formed by anhydride bonds.

  12. 2-Fatty acrylic acids: new highly derivatizable lipophilic platform molecules

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper reports the incorporation of an alpha-methylene unit into fatty acid skeletons. Since the new olefin is conjugated with the carboxylate, it is susceptible to 1,4- (Michael) additions. We have used multifunctional thiols and amines for additions at the methylene. The resulting products ...

  13. Phase Transition of Poly(acrylic acid-co-N-isopropylacrylamide) Core-shell Nanogels

    NASA Astrophysics Data System (ADS)

    Liu, Xiao-bing; Zhou, Jian-feng; Ye, Xiao-dong

    2012-08-01

    A series of poly(acrylic acid) macromolecular chain transfer agents with different molecular weights were synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization and characterized by 1H NMR and gel permeation chromatography. Multiresponsive core-shell nanogels were prepared by dispersion polymerization of N-isopropylacrylamide in water using these poly(potassium acrylate) macro-RAFT agents as the electrosteric stabilizer. The size of the nanogels decreases with the amount of the macro-RAFT agent, indicating that the surface area occupied by per polyelectrolyte group is a critical parameter for stabilizing the nanogels. The volume phase transition and the zeta potentials of the nanogels in aqueous solutions were studied by dynamic light scattering and zetasizer analyzer, respectively.

  14. Electrospinning of Bioactive Dex-PAA Hydrogel Fibers

    NASA Astrophysics Data System (ADS)

    Louie, Katherine Boyook

    In this work, a novel method is developed for making nano- and micro-fibrous hydrogels capable of preventing the rejection of implanted materials. This is achieved by either (1) mimicking the native cellular environment, to exert fine control over the cellular response or (2) acting as a protective barrier, to camouflage the foreign nature of a material and evade recognition by the immune system. Comprehensive characterization and in vitro studies described here provide a foundation for developing substrates for use in clinical applications. Hydrogel dextran and poly(acrylic acid) (PAA) fibers are formed via electrospinning, in sizes ranging from nanometers to microns in diameter. While "as-electrospun" fibers are continuous in length, sonication is used to fragment fibers into short fiber "bristles" and generate nano- and micro- fibrous surface coatings over a wide range of topographies. Dex-PAA fibrous surfaces are chemically modified, and then optimized and characterized for non-fouling and ECM-mimetic properties. The non-fouling nature of fibers is verified, and cell culture studies show differential responses dependent upon chemical, topographical and mechanical properties. Dex-PAA fibers are advantageously unique in that (1) a fine degree of control is possible over three significant parameters critical for modifying cellular response: topography, chemistry and mechanical properties, over a range emulating that of native cellular environments, (2) the innate nature of the material is non-fouling, providing an inert background for adding back specific bioactive functionality, and (3) the fibers can be applied as a surface coating or comprise the scaffold itself. This is the first reported work of dex-PAA hydrogel fibers formed via electrospinning and thermal cross-linking, and unique to this method, no toxic solvents or cross-linking agents are needed to create hydrogels or for surface attachment. This is also the first reported work of using sonication to

  15. Radiation synthesis of eco-friendly water reducing sulfonated starch/acrylic acid hydrogel designed for cement industry

    NASA Astrophysics Data System (ADS)

    Abd El-Rehim, H. A.; Hegazy, El-Sayed A.; Diaa, D. A.

    2013-04-01

    Starch was treated with chlorosulfonic acid to obtain sulfonated starch. Acrylic acid/sulfonated starch semi-interpenetrated network IPN of different compositions was prepared using ionizing radiation. Swelling of prepared IPNs at different environmental conditions was studied. The possible use of sulfonated starch/acrylic acid IPN as a water-retarding agent in the cement industry was investigated. ζ-potential measurements were used to determine the stability of the colloidal cement—SS/AA and cement -poly-naphthalene sulfonic acid (SNF) water retarding mixtures. Sulfonated starch/acrylic acid water-retarding property was influenced by hydrogel concentration and composition. Sulfonated starch/acrylic acid IPN admixture has a great effect on the cement initial setting time. Using 2% of SS/AA or SNF resulted in an increase in initial setting time by 2 and 1 h respectively, if compared with native cement initial setting time. The results showed that the synthetic commercial super-plasticizers could be replaced by an eco-friendly water-retarding sulfonated starch/acrylic acid IPN in the cement industry.

  16. Salicylic acid-releasing polyurethane acrylate polymers as anti-biofilm urological catheter coatings.

    PubMed

    Nowatzki, Paul J; Koepsel, Richard R; Stoodley, Paul; Min, Ke; Harper, Alan; Murata, Hironobu; Donfack, Joseph; Hortelano, Edwin R; Ehrlich, Garth D; Russell, Alan J

    2012-05-01

    Biofilm-associated infections are a major complication of implanted and indwelling medical devices like urological and venous catheters. They commonly persist even in the presence of an oral or intravenous antibiotic regimen, often resulting in chronic illness. We have developed a new approach to inhibiting biofilm growth on synthetic materials through controlled release of salicylic acid from a polymeric coating. Herein we report the synthesis and testing of a ultraviolet-cured polyurethane acrylate polymer composed, in part, of salicyl acrylate, which hydrolyzes upon exposure to aqueous conditions, releasing salicylic acid while leaving the polymer backbone intact. The salicylic acid release rate was tuned by adjusting the polymer composition. Anti-biofilm performance of the coatings was assessed under several biofilm forming conditions using a novel combination of the MBEC Assay™ biofilm multi-peg growth system and bioluminescence monitoring for live cell quantification. Films of the salicylic acid-releasing polymers were found to inhibit biofilm formation, as shown by bioluminescent and GFP reporter strains of Pseudomonas aeruginosa and Escherichia coli. Urinary catheters coated on their inner lumens with the salicylic acid-releasing polymer significantly reduced biofilm formation by E. coli for up to 5 days under conditions that simulated physiological urine flow.

  17. Electrochemical investigations of 3-(3-thienyl) acrylic acid protected nanoclusters and planar gold surfaces.

    PubMed

    Nirmal, R G; Kavitha, A L; Berchmans, Sheela; Yegnaraman, V

    2007-06-01

    Formation of self assembled monolayers on gold surface by thiols and disulphides is a well known phenomenon and extensive research work has been carried out in this area with envisaged applications in the area of sensors, molecular electronics, lithography, device fabrication using bottom-up approach, etc. Recently, it has been established that thiophene molecules can self assemble on gold surface due to Au-S interactions. 3-(3-thienyl) acrylic acid, a bifunctional ligand is used in this work to form self-assembled monolayers on planar gold surfaces (two dimensional assemblies) and to prepare monolayer protected gold nano clusters (three-dimensional assemblies). The electron transfer blocking properties of the two-dimensional monolayers were evaluated by using standard redox probes like ferrocyanide anions and Ruthenium hexamine cations. The functionalisation of the two-dimensional and three-dimensional assemblies has been carried out with ferrocene carboxylic acid and the functionalised monolayers were characterized by Cyclic voltammetry. The formation of thienyl acrylic acid protected nanoclusters has been verified by TEM and surface plasmon resonance absorption. It has been observed that when thiophene based ligands are used as stabilizers for the formation of metal nanoparticles, they tend to aggregate as a result of pi-pi interactions between adjacent thiophene ligands. In this case it is found that aggregation is prevented. The substituent at the thiophene ring hinders pi-pi interactions. The quantised nature of electrochemical charging of these nanoparticles has been demonstrated by differential pulse voltammetry (DPV), which exhibit peak like features (coulomb's staircase). This work also explores the possibility of using 3-(3-thienyl) acrylic acid as building blocks or spacers on planar and colloidal gold surfaces for potential applications in the field of sensors and devices.

  18. Grafting acrylic acid onto polypropylene by reactive extrusion with pre-irradiated PP as initiator

    NASA Astrophysics Data System (ADS)

    Cai, Chuanlun; Shi, Qiang; Li, Lili; Zhu, Lianchao; Yin, Jinghua

    2008-03-01

    In this paper, the modification of polypropylene (PP) with acrylic acid (AA) by reactive extrusion using pre-irradiated PP (rPP) as initiator was investigated. It was found the relatively high graft degree (Gd) and slight degradation of modified PP was obtained when 20 wt% rPP was used. This result can be explained in terms of effective concentration of free radicals. Compared with the neat PP, the modified PP showed the high-notched impact strength and improved adhesion of PP to polar substrate. This technique is of potential industrial interest for PP modification.

  19. Surface component distribution in a vanadium-molybdenum oxide catalyst for making acrylic acid from acrolein

    SciTech Connect

    Zazhigalov, V.A.; Kholyavenko, K.M.

    1986-11-01

    A scanning electron microscope and microprobe analyzer have been used to examine the surfaces of vanadium-molybdenum catalysts on aerosil. It is found that the phase VMo/sub 3/O/sub 11/ is formed, which is dispersed on the SiO/sub 2/. MoO/sub 3/ crystals of various shapes occur at the surface of the dispersed phase. It is suggested that this catalyst is highly active in oxidizing acrolein to acrylic acid because of the presence of VMo/sub 3/O/sub 11/.

  20. Pharmacokinetics of copolymers of N-vinylpyrrolidone with acrylic acid. Article 1

    SciTech Connect

    Rafikov, R.Z.; Sakhibov, A.D.; Akhmedzhanov, R.I.; Aliev, K.U.

    1987-01-01

    The authors studied the pharmacokinetics of the copolymers of n-vinyl-pyrrolidone (I) with acrylic acid (II) (copolymer III) using the radioactive isotope /sup 125/I. In experiments on mice, they studied the distribution of a copolymer of I with II (/sup 125/I-III) in the organism of the animals. The content of /sup 125/I-III and its possible radioactive metabolites in the blood and organs of mice after a single intravenous administration of the given preparation is shown. The radioactivity of organs after butanol extraction is presented.

  1. Thermal destruction of copolymers of polypropylene glycol maleate with acrylic acid

    NASA Astrophysics Data System (ADS)

    Burkeev, M. Zh.; Sarsenbekova, A. Zh.; Tazhbaev, E. M.; Figurinene, I. V.

    2015-12-01

    The results from thermogravimetric and kinetic studies of copolymers of polypropylene glycol maleate with acrylic acid at different molar ratios are presented. The results from conventional thermogravimetric studies are used to determine kinetic characteristics of the process of thermal decomposition, i.e., activation energy and pre-exponential factors. These parameters are determined in three ways: the Achar, Freeman-Carroll, and Sharp-Wentworth methods. Activation energies calculated using all the three methods confirm the dependence of the destruction process on the ratio of components in a synthesized copolymer. It is shown that the obtained values of the activation energies and thermodynamic characteristics allow us to predict a copolymer's composition.

  2. Synthesis of carboxymethylcellulose/acrylic acid hydrogels with superabsorbent properties by radiation-initiated crosslinking

    NASA Astrophysics Data System (ADS)

    Fekete, Tamás; Borsa, Judit; Takács, Erzsébet; Wojnárovits, László

    2016-07-01

    Superabsorbent hydrogels were prepared by gamma irradiation from aqueous solutions of carboxymethylcellulose (CMC) and acrylic acid (AAc) with varying CMC:AAc ratio. By partially replacing the CMC with AAc the gelation increased and led to a higher gel fraction and lower water uptake. Moreover, the gelation required significantly milder synthesis conditions. Decreasing both the dose and the solute concentration in the presence of AAc led to gels with higher gel fraction and higher degree of swelling compared to pure CMC gels. Increasing the AAc content up to 10% proved to be very effective, while very high AAc content (over 50%) hindered the gelation process.

  3. Aliphatic amidase of Rhodococcus rhodochrous PA-34: Purification, characterization and application in synthesis of acrylic acid.

    PubMed

    Thakur, Neerja; Kumar, Vijay; Sharma, Nirmal Kant; Thakur, Shikha; Bhalla, Tek Chand

    2016-01-01

    An intracellular aliphatic amide degrading inducible amidase produced by Rhodococcus rhodochrous PA-34 was characterized and acrylic acid synthesis from acrylamide was carried out using whole cell amidase. A bioprocess was developed at 50 ml fed batch reaction using 400 mM acrylamide feeding at an interval of 30 min resulted in the production of 4 g acrylic acid with volumetric and catalytic productivity of 80 g/l and 19 g/g/h respectively. The amidase of this organism had molecular weight of 40 kDa and was purified to 8.5 fold with 8% yield. This enzyme was active within the temperature range of 30 to 60 °C, with optimum temperature 45 °C and pH 7.5. The Vmax, Km, and kcat of purified amidase were calculated as 250 U/mg protein, 4.5 mM, and 166 sec-1 for acrylamide. The enzyme showed tolerance to metal chelating agent (EDTA) and was strongly inhibited by heavy metal ions Hg2+, Ag2+, Cu2+ and Co2+. R. rhodochrous PA-34 amidase preferentially hydrolyzed small aliphatic toxic amide such as acrylamide. Thus, the amidase of R. rhodochrous PA-34 is promising biocatalyst for the synthesis of industrially important acids and biodegradation of toxic amides. PMID:26667322

  4. Multielement crystalline and pseudocrystalline oxides as efficient catalysts for the direct transformation of glycerol into acrylic acid.

    PubMed

    Chieregato, Alessandro; Soriano, M Dolores; García-González, Ester; Puglia, Giuseppe; Basile, Francesco; Concepción, Patricia; Bandinelli, Claudia; López Nieto, José M; Cavani, Fabrizio

    2015-01-01

    Glycerol surplus from biodiesel synthesis still represents a major problem in the biofuel production chain. Meanwhile, those in the acrylic acid market are looking for new processes that are able to offer viable alternatives to propylene-based production. Therefore, acrylic acid synthesis from glycerol could be an effective solution to both issues. Among the viable routes, one-pot synthesis theoretically represents the most efficient process, but it is also highly challenging from the catalyst design standpoint. A new class of complex W--Mo--V mixed-oxide catalysts, which are strongly related to the hexagonal tungsten bronze structure, able to directly convert glycerol into acrylic acid with yields of up to 51 % are reported. PMID:25488515

  5. Topological characterization of a bacterial cellulose-acrylic acid polymeric matrix.

    PubMed

    Halib, N; Mohd Amin, M C I; Ahmad, I; Abrami, M; Fiorentino, S; Farra, R; Grassi, G; Musiani, F; Lapasin, R; Grassi, M

    2014-10-01

    This paper focuses on the micro- and nano-topological organization of a hydrogel, constituted by a mixture of bacterial cellulose and acrylic acid, and intended for biomedical applications. The presence of acrylic acid promotes the formation of two interpenetrated continuous phases: the primary "pores phase" (PP) containing only water and the secondary "polymeric network phase" (PNP) constituted by the polymeric network swollen by the water. Low field Nuclear Magnetic Resonance (LF NMR), rheology, Scanning Electron Microscopy (SEM) and release tests were used to determine the characteristics of the two phases. In particular, we found that this system is a strong hydrogel constituted by 81% (v/v) of PP phase the remaining part being occupied by the PNP phase. Pores diameters span in the range 10-100 μm, the majority of them (85%) falling in the range 30-90 μm. The high PP phase tortuosity indicates that big pores are not directly connected to each other, but their connection is realized by a series of interconnected small pores that rend the drug path tortuous. The PNP is characterized by a polymer volume fraction around 0.73 while mesh size is around 3 nm. The theoretical interpretation of the experimental data coming from the techniques panel adopted, yielded to the micro- and nano-organization of our hydrogel. PMID:24932712

  6. Acrylic acid grafted cellulosic Luffa cylindrical fiber for the removal of dye and metal ions.

    PubMed

    Gupta, Vinod Kumar; Agarwal, Shilpi; Singh, Prerna; Pathania, Deepak

    2013-10-15

    Acrylic acid grafted cellulosic Luffa cylindrical fiber was utilized for the removal of methylene blue and metal ions from the water system using batch process. The grafted sample used was found to demonstrate a maximum grafting efficiency of 90.8% under concentrations of 0.432×10(-3) mol/L, temperature of 35 °C, time of 60 min and pH of 7.0 respectively. The remarkable improvement in thermal properties of the grafted sample was observed. The formation of new bands in FTIR spectra of grafted sample confirmed the grafting of acrylic acid onto the cellulosic fiber. The maximum adsorption capacity of dye onto adsorbent was observed to be 62.15 mg g(-1) at 175 min. A maximum removal of 45.8% was observed for Mg(2+) as compared to other metal ions. High values of correlation coefficient for methylene blue (0.995) and metal ions such as Mg(2+) (0.996), Ni(2+) (0.995), Zn(2+) (0.996) confirmed the applicability of Langmuir isotherm that assumed a monolayer coverage and uniform activity distribution on the adsorbent surface.

  7. Characterization of thin-film deposition in a pulsed acrylic acid polymerizing discharge

    SciTech Connect

    Voronin, Sergey A.; Bradley, James W.; Fotea, Catalin; Zelzer, Mischa; Alexander, Morgan R.

    2007-07-15

    In this study, thin-film deposition in a pulsed rf polymerizing discharge (13.56 MHz) struck in acrylic acid has been investigated by mass spectrometry, x-ray photoelectron spectroscopy, and quartz crystal microbalance techniques. The experiment was conducted at a fixed acrylic acid pressure of 1.3 Pa and 'on' pulse duration of 0.1 ms, whereas the 'off' time was varied between 0 and 20 ms. The rf input power in the 'on' time and gas flow rate were varied between 10 and 50 W and 1.5 and 4.8 sccm (sccm denotes cubic centimeter per minute at STP), respectively. These changes of the discharge conditions resulted in large-scale progressive variations in film and gas-phase plasma composition. In particular, the -COOH functionality of the monomer was increasingly retained in the plasma-generated thin films as the duty cycle was lowered (i.e., with lowered time-averaged powers). The monomer retention reached its maximum value of 66% for 'off' times exceeding 5 ms, when the discharge was operating in the power-deficient regime. The results show that the film deposition rate is a strong function of the monomer flow rate, whereas -COOH retention is correlated to the amount of unfragmented monomer in the plasma, controlled by the applied power.

  8. Precipitation-Redispersion of Cerium Oxide Nanoparticles with Poly(acrylic acid): Toward Stable Dispersions

    SciTech Connect

    Sehgal,A.; Lalatonne, Y.; Berret, J.; Morvan, M.

    2005-01-01

    We exploit a precipitation-redispersion mechanism for complexation of short chain polyelectrolytes with cerium oxide nanoparticles to extend their stability ranges. As synthesized, cerium oxide sols at pH 1.4 consist of monodisperse cationic nanocrystalline particles having a hydrodynamic diameter of 10 nm and a molecular weight of 400 000 g mol{sup -1}. We show that short chain uncharged poly(acrylic acid) at low pH when added to a cerium oxide sols leads to macroscopic precipitation. As the pH is increased, the solution spontaneously redisperses into a clear solution of single particles with an anionic poly(acrylic acid) corona. The structure and dynamics of cerium oxide nanosols and their hybrid polymer-inorganic complexes in solution are investigated by static and dynamic light scattering, X-ray scattering, and chemical analysis. Quantitative analysis of the redispersed sol gives rise to an estimate of 40-50 polymer chains per particle for stable suspension. This amount represents 20% of the mass of the polymer-nanoparticle complexes. This complexation adds utility to the otherwise unstable cerium oxide dispersions by extending the range of stability of the sols in terms of pH, ionic strength, and concentration.

  9. MexAB-OprM specific efflux pump inhibitors in Pseudomonas aeruginosa. Part 4: Addressing the problem of poor stability due to photoisomerization of an acrylic acid moiety.

    PubMed

    Nakayama, Kiyoshi; Kuru, Noriko; Ohtsuka, Masami; Yokomizo, Yoshihiro; Sakamoto, Atsunobu; Kawato, Haruko; Yoshida, Ken-ichi; Ohta, Toshiharu; Hoshino, Kazuki; Akimoto, Katsuya; Itoh, Junko; Ishida, Hiroko; Cho, Aesop; Palme, Monica H; Zhang, Jason Z; Lee, Ving J; Watkins, William J

    2004-05-17

    Exchange of the ethylene tether in a series of pyridopyrimidine-based MexAB-OprM specific efflux pump inhibitors to an amide bond stabilized the olefin of the acrylic acid moiety, preventing facile photoisomerization to the Z-isomer. Furthermore, the activity was drastically improved in the amide tether variants, providing extremely potent acrylic acid and vinyl tetrazole analogues.

  10. Peptide immobilization onto radiation grafted PVDF-g-poly(acrylic acid) films

    NASA Astrophysics Data System (ADS)

    Clochard, M.-C.; Betz, N.; Goncalves, M.; Bittencourt, C.; Pireaux, J.-J.; Gionnet, K.; Déléris, G.; Moël, A. Le

    2005-07-01

    Introducing hydrophilic functions on poly(vinylidene fluoride) (PVDF) films surface allows the covalent immobilization of peptides. Therefore radiation grafting of acrylic acid (AA) in pre-irradiated PVDF films was achieved to allow surface functionalization with linear and cyclic peptides. Peptides were bound via spacer molecules using EDC as a coupling agent. The reactions were followed by Fourier Transform Infrared (FTIR) spectroscopy in attenuated total reflection (ATR) mode. The amount of immobilized peptides was determined by UV spectroscopy. As well, an uncommon method for PVDF characterization and reactions quantification was used: high-resolution-magic angle spinning nuclear mass spectroscopy (HR-MAS NMR). Spacer saturation of the film surface corresponded to 25 mol% yield meaning that one spacer on 4 carboxylic acids was covalently bound. XPS experiments were also performed to deepen analysis of the surface composition. Peptide density is governed by steric hindrance. ELISA tests showed that the peptides' activity is maintained.

  11. The active component of vanadium-molybdenum catalysts for the oxidation of acrolein to acrylic acid

    SciTech Connect

    Andrushkevich, T.V.; Kuznetsova, T.G.

    1986-12-01

    The catalytic properties of the vanadium-molybdenum oxide system were investigated in the oxidation of acrolein to acrylic acid. The active component of the catalyst is the compound VMo/sub 3/O/sub 11/, the maximum amount of which is observed at a content of 7-15 mole% V/sub 2/O/sub 4/. The compound VMo/sub 3/O/sub 11/ is formed in the thermodecomposition of silicomolybdovanadium heteropoly acids or isopoly compounds, reduced with respect to vanadium, and contains V/sup 4 +/ and Mo/sup 6 +/. The optimum treatment for the formation of this compound is treatment in the reaction mixture at 400 degrees C.

  12. Covalently-layers of PVA and PAA and in situ formed Ag nanoparticles as versatile antimicrobial surfaces.

    PubMed

    Fragal, Vanessa H; Cellet, Thelma S P; Pereira, Guilherme M; Fragal, Elizângela H; Costa, Marco Antonio; Nakamura, Celso Vataru; Asefa, Tewodros; Rubira, Adley F; Silva, Rafael

    2016-10-01

    The in situ synthesis of silver nanoparticles (AgNPs) within covalently-modified poly(ethylene terephthalate) (PET) films possessing ultra-thin layer of poly(vinyl alcohol) (PVA) and poly(acrylic acid) (PAA) is successfully demonstrated. The resulting polymeric films are shown to exhibit antimicrobial activities toward Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria and fungus (Candida albicans). To make the films, first PET surfaces were subject to photo-oxidation and subsequent solid-state grafting to attach a PVA layer, followed by a PAA layer. To synthesize the AgNPs inside the films, the PVA and PAA-modified PET was soaked in AgNO3 solution and the polymeric film was modified with the Ag(+) ions via Ag(+)-carboxylate interaction, and then the Ag(+) ions-containing polymer film was subject to either photo-reduction or thermal reduction processes. The PVA and PAA thin layers attached by covalent bonds to the PET surface uniquely promoted not only the in situ synthesis but also the stabilization of AgNPs. The formation of the AgNPs was confirmed by UV-vis spectroscopy or by monitoring the surface plasmon resonance (SPR) peak associated with AgNPs. The resulting PVA and PAA ultrathin layers modified and AgNPs containing PET served as bactericide and fungicide, inhibiting the growth of bacteria and fungi on the surfaces. Given PET's versatility and common use in many commercial processes, the method can be used for producing plastic surfaces with versatile antimicrobial and antibacterial properties. PMID:27196366

  13. Synthesis and self-assembly of PAMAM/PAA Janus dendrimers

    NASA Astrophysics Data System (ADS)

    Gao, Chunmei; Liu, Mingzhu; Lü, Shaoyu; Zhang, Xinjie; Chen, Yuanmou

    2014-03-01

    Janus dendrimers have two differently functionalized segments which are located on opposite sides. They have many excellent properties and broad application prospects. In this study, poly(amido amine)/poly(acrylic acid) (PAMAM/PAA) Janus dendrimers were prepared by click chemistry. One of the first steps taken was the synthesis of N-Boc-G3.0 PAMAM dendrimers with primary amine groups at the periphery. Second, by amide coupling between propargylic acid and N-Boc-G3.0 PAMAM, PAMAM dendrimers with alkyne were successfully synthesized. After being dissolved in aqueous solutions with different pH, Janus dendrimers spontaneously form flowerlike micellar, Janus particles, and spherical micelles due to primary amino, tertiary amino, and carboxyl groups in the dendrimers. This self-assembly behavior depending on pH changes has a number of potential applications in the field of materials.

  14. Preparation and drug-loading properties of Fe3O4/Poly(styrene-co-acrylic acid) magnetic polymer nanocomposites

    NASA Astrophysics Data System (ADS)

    Lu, Wensheng; Shen, Yuhua; Xie, Anjian; Zhang, Weiqiang

    2013-11-01

    Fe3O4/poly(styrene-co-acrylic acid) magnetic polymer nanocomposites were synthesized by the dispersion polymerization method using styrene as hard monomer, acrylic acid as functional monomer, Fe3O4 nanoparticles modified with oleic acid as core, and poly(styrene-co-acrylic acid) as shell. Drug-loading properties of magnetic polymer nanocomposites with curcumin as a model drug were also studied. The results indicated that magnetic polymer nanocomposites with monodisperse were obtained, the particle size distribution was 50-120 nm, and the average size was about 100 nm. The contents of poly(styrene-co-acrylic acid) and Fe3O4 nanoparticles in magnetic polymer nanocomposites were 74% and 24.7%, respectively. The drug-loading capacity and entrapment efficiency were 2.5% and 44.4%, respectively. The saturation magnetization of magnetic polymer nanocomposites at 300 K was 20.2 emu/g without coercivity and remanence. The as-prepared magnetic polymer nanocomposites have not only lots of functional carboxyl groups but also stronger magnetic response, which might have potential applications in drug carrier and targeted drug release.

  15. Novel one-dimensional lanthanide acrylic acid complexes: an alternative chain constructed by hydrogen bonding

    NASA Astrophysics Data System (ADS)

    Li, Hui; Hu, Chang Wen

    2004-12-01

    Novel one-dimensional (1D) chains of three lanthanide complexes La(L 1) 3(CH 3OH)]·CH 3OH (L 1=(E)-3-(2-hydroxyl-phenyl)-acrylic acid) 1, La(L 2) 3(H 2O) 2]·2.75H 2O (L 2=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) 2, and La(L 3) 3(CH 3OH) 2(H 2O)]·CH 3OH (L 3=(E)-3-(4-hydroxyl-phenyl)-acrylic acid) 3 are reported. The crystal structure data are as follows for 1: C 29H 29LaO 11, monoclinic, P2 1/ n, a=15.4289(12) Å, b=7.9585(6) Å, c=23.041(2) Å, β=99.657(2)°, Z=4, R1=0.0637, w R2=0.0919; for 2: C 27H 30.50LaO 13.75, triclinic, P-1, a=8.4719(17) Å, b=13.719(3) Å, c=14.570(3) Å, α=62.19(3)°, β=99.657(2)°, γ=78.22(3)°, Z=2, R1=0.0384, w R2=0.0820; and for 3: C 30H 35LaO 13, monoclinic, P2(1)/ c, a=9.5667(6) Å, b=24.3911(15) Å, c=14.0448(9) Å, β=109.245(2)°, Z=4, R1=0.0374, w R2=0.0630. All the three structure data were collected using graphite monochromated molybdenum Kα radiation and refined using full-matrix least-squares techniques on F 2. These structures show that four kinds of the carboxylato bridge modes are included in these chains to link the La(III) ions. It is the first time that it has been found that the intra-chain hydrogen bonding can construct an alternative chain even, when the coordination bridge mode is the same along the chain (complex 2). There are 2D and 3D hydrogen bonding in the crystal lattices of complexes 1- 3.

  16. Ex vivo bioadhesion and in vivo testosterone bioavailability study of different bioadhesive formulations based on starch-g-poly(acrylic acid) copolymers and starch/poly(acrylic acid) mixtures.

    PubMed

    Ameye, D; Voorspoels, J; Foreman, P; Tsai, J; Richardson, P; Geresh, S; Remon, J P

    2002-02-19

    Starch-g-poly(acrylic acid) copolymers or grafted starches synthesized by 60Co irradiation or chemical modification and co-freeze-dried starch/poly(acrylic acid) mixtures were evaluated on their ex vivo bioadhesion capacity. The buccal absorption of testosterone from a bioadhesive tablet formulated with the grafted starches or starch/poly(acrylic acid) mixtures was investigated. The results were compared to a reference formulation (physical mixture of 5% Carbopol 974P and 95% Drum Dried Waxy Maize). Rice starch-based irradiated grafted starches showed the best bioadhesion results. Partial neutralization of the acrylic acid with Ca(2+) ions resulted in significantly higher bioadhesion values compared to the reference. Ca(2+) and Mg(2+) partially neutralized maltodextrin-based irradiated grafted starches showed significantly higher bioadhesion values compared to the reference formulation. The chemically modified grafted starches showed significantly higher adhesion force values than for the reference tablet. None of the co-freeze-dried starch/poly(acrylic acid) mixtures showed significantly higher bioadhesion results than the reference (Bonferroni test, P<0.05). A chemically modified grafted starch could sustain the 3 ng/ml plasma testosterone target concentration during +/- 8 h (T(>3 ng/ml)). By lyophilization of a partially neutralized irradiated grafted starch, the in vivo adhesion time (22.0 +/- 7.2 h) and the T(>3 ng/ml) (13.5 +/- 1.3 h) could be increased. The absolute bioavailability of the lyophilized formulation approached the reference formulation. Some of the grafted starches showed to be promising buccal bioadhesive drug carriers for systemic delivery. PMID:11853929

  17. A stencil printed, high energy density silver oxide battery using a novel photopolymerizable poly(acrylic acid) separator.

    PubMed

    Braam, Kyle; Subramanian, Vivek

    2015-01-27

    A novel photopolymerized poly(acrylic acid) separator is demonstrated in a printed, high-energy-density silver oxide battery. The printed battery demonstrates a high capacity of 5.4 mA h cm(-2) at a discharge current density of 2.75 mA cm(-2) (C/2 rate) while delivering good mechanical flexibility and robustness. PMID:25475759

  18. Properties of amylose-oleic acid inclusion complexes from corn starch grafted with poly(methyl acrylate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn starch granules have been previously investigated as fillers in polymers. In this study, much smaller particles in the form of spherulites produced by steam jet-cooking high-amylose corn starch and oleic acid to form amylose inclusion complexes were graft polymerized with methyl acrylate, both ...

  19. Photoinduced Graft-Polymerization of Acrylic Acid on Polyethylene and Polypropylene Surfaces: Comparative Study Using IR-ATR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Gorbachev, A. A.; Tretinnikov, O. N.; Shkrabatovskaya, L. V.; Prikhodchenko, L. K.

    2014-11-01

    Photoinduced graft-polymerization of acrylic acid on the surface of polyethylene and polypropylene films containing a photoinitiator pre-adsorbed from a thin layer of non-de-aerated aqueous monomer solution was investigated. Data about the monomer conversion and grafting depth as functions of the UV irradiation time and polymer nature were obtained using IR-ATR spectroscopy.

  20. Structure-function properties of amylose-oleic acid inclusion complexes grafted with poly(methyl acrylate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spherulites, produced by steam jet-cooking high-amylose starch and oleic acid, were grafted with methyl acrylate, both before and after removal of un-complexed amylopectin. For comparison, granular high-amylose corn starch was graft polymerized in a similar manner. The amount of grafted and ungrafte...

  1. A stencil printed, high energy density silver oxide battery using a novel photopolymerizable poly(acrylic acid) separator.

    PubMed

    Braam, Kyle; Subramanian, Vivek

    2015-01-27

    A novel photopolymerized poly(acrylic acid) separator is demonstrated in a printed, high-energy-density silver oxide battery. The printed battery demonstrates a high capacity of 5.4 mA h cm(-2) at a discharge current density of 2.75 mA cm(-2) (C/2 rate) while delivering good mechanical flexibility and robustness.

  2. Graft polymerization of acrylic acid onto chitin nanofiber to improve dispersibility in basic water.

    PubMed

    Ifuku, Shinsuke; Iwasaki, Masayoshi; Morimoto, Minoru; Saimoto, Hiroyuki

    2012-09-01

    Graft copolymerization of acrylic acid (AA) on chitin nanofibers was carried out with potassium persulfate as a free radical initiator in an aqueous medium. The molar ratio of grafted AA increased with the AA concentration. The grafted chitin nanofibers were characterized by FT-IR, FE-SEM, UV-vis, XRD, and TGA. After polymerization, the characteristic morphology of chitin nanofibers was maintained. Chitin nanofibers grafted with AA were efficiently dissociated and dispersed homogeneously in basic water because of the electrostatic repulsion effect between nanofibers. AA was grafted on the surface and amorphous part of chitin nanofibers, and the original crystalline structure of α-chitin was maintained. At 330 °C, the weight residue of the graft copolymer increased with the grafted AA content. PMID:24751085

  3. The graft polymers from different species of lignin and acrylic acid: synthesis and mechanism study.

    PubMed

    Ye, De zhan; Jiang, Li; Ma, Chao; Zhang, Ming-hua; Zhang, Xi

    2014-02-01

    The influence of lignin species on the grafting mechanism of lignosulfonate (from eucalyptus and pine, recorded as HLS and SLS, respectively) with acrylic acid (AA) was investigated. The graft polymers were confirmed by the absorption of carbonyl groups in the FTIR spectra. The decreasing phenolic group's content (Ph-OH) is not only due to its participation as grafting site but also to the negative effect of initiator. In the initial period (0-60 min), HLS and SLS both accelerate the polymerization of AA. Additionally, Ph-OH group's content is proportional to product yield (Y%), monomer conversion (C%) and grafting efficiency (GE%), strongly indicating that it acts as active center. Nevertheless, compared with HLS, Y% and C% in SLS grafting system are lower though it has higher Ph-OH group's content, which is due to the quinonoid structure formed by the self-conjugated of phenoxy radical in Guaiacyl unit. Finally, the lignosulfonate grafting mechanism was proposed. PMID:24076194

  4. Dyed acrylic-acid grafted polypropylene films for high-dose radiation dosimetry

    NASA Astrophysics Data System (ADS)

    Abdel-Fattah, A. A.; Said, F. I. A.; Ebraheem, S.; El-Kelany, M.; El Miligy, A. A.

    1999-03-01

    Gamma radiation-induced polymerization of acrylic acid (AAc) onto polypropylene (PP) film has been carried out under nitrogen atmosphere. The grafted film of PP-g-PAAc was allowed to react with solutions of two ionic dyes, namely malachite green (MALG) or methylene green (METG). The investigations show that these new dosimeter films of PPMALG and PPMETG may be useful for high-dose gamma radiation applications. The useful absorbed dose range of the dyed films extends up to about 400 kGy, with a minimum useful dose of about 5 kGy. The radiation-induced colour bleaching has been analyzed with visible spectrophotometry, either at the maximum of the absorption band peaking at 601 nm (for PPMETG) or that peaking at 623 nm for (PPMALG). The effects of relative humidity during irradiation, shelf-life and post-irradiation storage in dark and indirect daylight conditions on dosimeters performance are discussed.

  5. Dyes adsorption using a synthetic carboxymethyl cellulose-acrylic acid adsorbent.

    PubMed

    Zhang, Genlin; Yi, Lijuan; Deng, Hui; Sun, Ping

    2014-05-01

    Removal of noxious dyes is gaining public and technological attention. Herein grafting polymerization was employed to produce a novel adsorbent using acrylic acid and carboxymethyl cellulose for dye removal. Scanning electron microscopy and Fourier-transform infrared spectroscopy verified the adsorbent formed under optimized reaction conditions. The removal ratio of adsorbent to Methyl Orange, Disperse Blue 2BLN and malachite green chloride reached to 84.2%, 79.6% and 99.9%, respectively. The greater agreement between the calculated and experimental results suggested that pseudo second-order kinetic model better represents the kinetic adsorption data. Equilibrium adsorptions of dyes were better explained by the Temkin isotherm. The results implied that this new cellulose-based absorbent had the universality for removal of dyes through the chemical adsorption mechanism. PMID:25079652

  6. Study on swelling behaviour of hydrogel based on acrylic acid and pectin from dragon fruit

    NASA Astrophysics Data System (ADS)

    Abdullah, Mohd Fadzlanor; Lazim, Azwani Mat

    2014-09-01

    Biocompatible hydrogel based on acrylic acid (AA) and pectin was synthesized using gamma irradiation technique. AA was grafted onto pectin backbone that was extracted from dragon fruit under pH 3.5 and extracts and ethanol ratios (ER) 1:0.5. The optimum hydrogel system with high swelling capacity was obtained by varying the dose of radiation and ratio of pectin:AA. FTIR-ATR spectroscopy was used to verify the interaction while thermal properties were analyzed by TGA and DSC. Swelling studies was carried out in aqueous solutions with different pH values as to determine the pH sensitivity. The results show that the hydrogel with a ratio of 2:3 (pectin:AA) and 30 kGy radiation dose has the highest swelling properties at pH of 10.

  7. Synthesis and characterization of zinc chloride containing poly(acrylic acid) hydrogel by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Park, Jong-Seok; Kuang, Jia; Gwon, Hui-Jeong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Seob Khil, Myung; Nho, Young-Chang

    2013-07-01

    In this study, the characterization of zinc chloride incorporated into a poly(acrylic acid) (PAAc) hydrogel prepared by gamma-ray irradiation was investigated. Zinc chloride powder with different concentrations was dissolved in the PAAc solution, and it was crosslinked with gamma-ray irradiation. The effects of various parameters such as zinc ion concentration and irradiation doses on characteristics of the hydrogel formed were investigated in detail for obtaining an antibacterial wound dressing. In addition, the gel content, pH-sensitive (pH 4 or 7) swelling ratio, and UV-vis absorption spectra of the zinc particles in the hydrogels were characterized. Moreover, antibacterial properties of these new materials against Staphylococcus aureus and Escherichia coli strains were observed on solid growth media. The antibacterial tests indicated that the zinc chloride containing PAAc hydrogels have good antibacterial activity.

  8. Extruded films of blended chitosan, low density polyethylene and ethylene acrylic acid.

    PubMed

    Martínez-Camacho, A P; Cortez-Rocha, M O; Graciano-Verdugo, A Z; Rodríguez-Félix, F; Castillo-Ortega, M M; Burgos-Hernández, A; Ezquerra-Brauer, J M; Plascencia-Jatomea, M

    2013-01-16

    The obtaining of chitosan extruded films was possible by using low density polyethylene (LDPE) as a matrix polymer and ethylene-acrylic acid copolymer as an adhesive, in order to ensure adhesion in the interphase of the immiscible polymers. The obtained blend films were resistant; however, a reduction in the mechanical resistance was observed as chitosan concentration increased. The thermal stability of the films showed a certain grade of interaction between polymers as seen in FTIR spectra. The antifungal activity of the extruded films was assessed against Aspergillus niger and high inhibition percentages were observed, which may be mainly attributed to barrier properties of the extruded films and the limited oxygen availability, resulting in the inability of the fungi to grow. A low adherence of fungal spores to the material surface was observed, mainly in areas with chitosan clumps, which can serve as starting points for material degradation.

  9. SYNTHESIS AND CHARACTERIZATION OF SUBSTITUTED POLY(STYRENE)-b-POLY(ACRYLIC ACID) BLOCK COPOLYMER MICELLES

    SciTech Connect

    Pickel, Deanna L; Pickel, Joseph M; Devenyi, Jozsef; Britt, Phillip F

    2009-01-01

    Block copolymer micelle synthesis and characterization has been extensively studied. In particular, most studies have focused on the properties of the hydrophilic corona due to the micelle corona structure s impact on the biodistribution and biocompatibility. Unfortunately, less attention has been given to the effect of the core block on the micelle stability, morphology, and the rate of diffusion of small molecules from the core. This investigation is focused on the synthesis of block copolymers composed of meta-substituted styrenes and acrylic acid by Atom Transfer Radical Polymerization. Micelles with cores composed of substituted styrenes having Tgs ranging from -30 to 100 oC have been prepared and the size and shape of these micelles were characterized by Static and Dynamic Light Scattering and TEM. In addition, the critical micelle concentration and rate of diffusion of small molecules from the core were determined by fluorimetry using pyrene as the probe.

  10. Terpolymers of ethyl acrylate/methacrylic acid/unsaturated acid ester of alcohols and acids as anti-settling agents in coal water slurries

    SciTech Connect

    Savoly, A.; Villa, J.L.; Grinstein, R.H.; Nachfolger, S.J.

    1988-05-17

    This patent describes a pumpable stabilized coal water slurry, having a coal content of at least about 50% by weight wherein at least 80% of the coal particles are about 200 mesh or finer, containing from about 0.01% to about 1% by weight of the slurry of a water soluble terpolymer of ethylacrylate (A), metacrylic acid (B) and a third monomer (C) selected from the group consisting of an unsaturated carboxylic acid ester of an alcohol and an ethoxylated carboxylic acid. The unsaturated carboxylic acid is a mono- or di- basic unsaturated carboxylic acid of 3 to 10 carbon atoms selected from the group consisting of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid.

  11. Self-assembly and the hemolysis effect of monodisperse N,N-diethylacrylamide/acrylic acid nanogels with high contents of acrylic acid.

    PubMed

    Li, Xueting; Zhao, Di; Shi, Xiaodi; Qiu, Gao; Lu, Xihua

    2016-09-21

    Monodisperse temperature/pH sensitive poly(N,N-diethylacrylamide/acrylic acid) (P(DEA/AAc)) nanogels with high contents of AAc up to 40 wt% have been prepared. In this study, it was unexpectedly found that the polydispersity of the nanogels with 40 wt% AAc strongly depended on the initiator concentration. Monodisperse P(DEA/AA) nanogels were synthesized only at a very low concentration of initiator. The phase transition behavior of the nanogels in water can be tuned by pH and temperature. Due to low polydispersity, the nanogels self-assembled into colloidal crystals at different temperatures below the volume phase transition temperature (VPTT). The sharp Bragg peaks of the crystals were significantly blue-shifted as the concentration of the nanogels was increased. In contrast, the condensed suspensions without crystals still exhibited clear colours resulting from a short-range order structure. The reflection spectra of the coloured suspensions showed that the peak wavelength became a bit longer and much broader. And the reflection intensity of the coloured suspensions was much weaker. Elastic and coloured crosslinked nanogel networks prepared by a one-pot and rapid light-initiated crosslinking method showed responses to pH and temperature. Furthermore, the interaction between the nanogels and peptide melittin was investigated. The results showed that an increasing AAc composition led to more efficient inhibition of the hemolytic activity of melittin. The nanogels with 40 wt% AAc composition completely inhibited hemolytic activity at a nanogel concentration of 400 µg ml(-1). Thus, monodisperse P(DEA/AAc) nanogels of high AAc composition may be developed as efficient substitutes for antibody-based antidotes. Owing to the combined influence of the periodic structure of the crystals of the nanogels and an efficient neutralization effect, the P(DEA/AAc) nanogels show promise to become an integral step for preparing valuable naked-eye biosensors as simple, cheap and

  12. Thiomers: Influence of molecular mass and thiol group content of poly(acrylic acid) on efflux pump inhibition.

    PubMed

    Grabovac, Vjera; Laffleur, Flavia; Bernkop-Schnürch, Andreas

    2015-09-30

    The aim of the present study was to investigate the influence of molecular mass and thiol group content of poly(acrylic acid)-cysteine conjugates on the permeation of sulforhodamine 101 and penicillin G. acting as substrates for multidrug resistance-associated protein 2 efflux pump. Poly(acrylic acids) of 2 kDa, 100 kDa, 250 kDa, 450 kDa and 3000 kDa were conjugated with cysteine. The thiol group content of all these polymers was in the range from 343.3 ± 48.4 μmol/g to 450.3 ± 76.1 μmol/g. Transport studies were performed on rat small intestine mounted in Ussing-type chambers. Since 250 kDa poly(acrylic acid) showed the highest permeation enhancing effect, additionally thiolated 250 kDa polyacrylates displaying 157.2 μmol/g, 223.0 ± 18.1 and 355.9 μmol/g thiol groups were synthesized in order to investigate the influence of thiol group content on the permeation enhancement. The permeation of sulforhodamine was 3.93- and 3.85-fold improved using 250 kDa poly(acrylic acid)-cysteine conjugate exhibiting 355.9 ± 39.5 μmol/g and 223.0 ± 18.1 μmol/g thiol groups. Using the same conjugates the permeation of penicillin G was 1.70- and 1.59-fold improved, respectively. The study demonstrates that thiolated poly(acrylic acid) inhibits Mrp2 mediated transport and that the extent of inhibition depends on the molecular mass and degree of thiolation of the polymer. PMID:26238816

  13. Thiomers: Influence of molecular mass and thiol group content of poly(acrylic acid) on efflux pump inhibition.

    PubMed

    Grabovac, Vjera; Laffleur, Flavia; Bernkop-Schnürch, Andreas

    2015-09-30

    The aim of the present study was to investigate the influence of molecular mass and thiol group content of poly(acrylic acid)-cysteine conjugates on the permeation of sulforhodamine 101 and penicillin G. acting as substrates for multidrug resistance-associated protein 2 efflux pump. Poly(acrylic acids) of 2 kDa, 100 kDa, 250 kDa, 450 kDa and 3000 kDa were conjugated with cysteine. The thiol group content of all these polymers was in the range from 343.3 ± 48.4 μmol/g to 450.3 ± 76.1 μmol/g. Transport studies were performed on rat small intestine mounted in Ussing-type chambers. Since 250 kDa poly(acrylic acid) showed the highest permeation enhancing effect, additionally thiolated 250 kDa polyacrylates displaying 157.2 μmol/g, 223.0 ± 18.1 and 355.9 μmol/g thiol groups were synthesized in order to investigate the influence of thiol group content on the permeation enhancement. The permeation of sulforhodamine was 3.93- and 3.85-fold improved using 250 kDa poly(acrylic acid)-cysteine conjugate exhibiting 355.9 ± 39.5 μmol/g and 223.0 ± 18.1 μmol/g thiol groups. Using the same conjugates the permeation of penicillin G was 1.70- and 1.59-fold improved, respectively. The study demonstrates that thiolated poly(acrylic acid) inhibits Mrp2 mediated transport and that the extent of inhibition depends on the molecular mass and degree of thiolation of the polymer.

  14. 808 nm photocontrolled UCL imaging guided chemo/photothermal synergistic therapy with single UCNPs-CuS@PAA nanocomposite.

    PubMed

    Liu, Bei; Li, Chunxia; Xie, Zhongxi; Hou, Zhiyao; Cheng, Ziyong; Jin, Dayong; Lin, Jun

    2016-08-16

    Recently, incorporating multiple components into one nanostructured matrix to construct a multifunctional nanomedical platform has attracted more and more attention for simultaneous anticancer diagnosis and therapy. Herein, a novel anti-cancer nanoplatform has been successfully developed by coating a uniform shell of poly(acrylic acid) (PAA) on the surface of CuS-decorated upconversion nanoparticles (UCNPs). Benefiting from the enhanced 808 nm-excited UCL intensity of the multilayer UCNPs, the unique photothermal properties of CuS and the pH-responsive drug release capacity of the PAA shell, such a nanoplatform design of UCNPs-CuS@PAA (labeled UCP) offers a new route to achieve 808 nm-excited UCL imaging guided chemo/photothermal combination therapy. We have found that the combined chemo/photothermal therapy can significantly improve the therapeutic efficacy compared with chemotherapy or photothermal therapy (PTT) alone. Moreover, the pH/NIR-dependent drug delivery properties, 808 nm-excited UCL imaging, as well as in vitro/in vivo biocompatibility tests were also investigated in detail. These results show promising applications of UCP nanoparticles as a novel theranostic agent for the detection and treatment of tumors. PMID:27529086

  15. Controlled release of insulin through hydrogels of (acrylic acid)/trimethylolpropane triacrylate

    NASA Astrophysics Data System (ADS)

    Raymundi, Vanessa C.; Aguiar, Leandro G.; Souza, Esmar F.; Sato, Ana C.; Giudici, Reinaldo

    2016-10-01

    Hydrogels of poly(acrylic acid) crosslinked with trimethylolpropane triacrylate (TMPTA) were produced through solution polymerization. After these hydrogels were loaded with insulin solution, they evidenced swelling. Experiments of controlled release of insulin through the hydrogels were performed in acidic and basic media in order to evaluate the rates of release of this protein provided by the referred copolymer. Additionally, a mathematical description of the system based on differential mass balance was made and simulated in MATLAB. The model consists of a system of differential equations which was solved numerically. As expected, the values of swelling index at the equilibrium and the rates of insulin release were inversely proportional to the degree of crosslinking. The mathematical model provided reliable predictions of release profiles with fitted values of diffusivity of insulin through the hydrogels in the range of 6.0 × 10-7-1.3 × 10-6 cm2/s. The fitted and experimental values of partition coefficients of insulin between the hydrogel and the medium were lower for basic media, pointing out good affinity of insulin for these media in comparison to the acidic solutions.

  16. Controlled release of insulin through hydrogels of (acrylic acid)/trimethylolpropane triacrylate

    NASA Astrophysics Data System (ADS)

    Raymundi, Vanessa C.; Aguiar, Leandro G.; Souza, Esmar F.; Sato, Ana C.; Giudici, Reinaldo

    2015-12-01

    Hydrogels of poly(acrylic acid) crosslinked with trimethylolpropane triacrylate (TMPTA) were produced through solution polymerization. After these hydrogels were loaded with insulin solution, they evidenced swelling. Experiments of controlled release of insulin through the hydrogels were performed in acidic and basic media in order to evaluate the rates of release of this protein provided by the referred copolymer. Additionally, a mathematical description of the system based on differential mass balance was made and simulated in MATLAB. The model consists of a system of differential equations which was solved numerically. As expected, the values of swelling index at the equilibrium and the rates of insulin release were inversely proportional to the degree of crosslinking. The mathematical model provided reliable predictions of release profiles with fitted values of diffusivity of insulin through the hydrogels in the range of 6.0 × 10-7-1.3 × 10-6 cm2/s. The fitted and experimental values of partition coefficients of insulin between the hydrogel and the medium were lower for basic media, pointing out good affinity of insulin for these media in comparison to the acidic solutions.

  17. Sustainable production of acrylic acid: alkali-ion exchanged beta zeolite for gas-phase dehydration of lactic acid.

    PubMed

    Yan, Bo; Tao, Li-Zhi; Liang, Yu; Xu, Bo-Qing

    2014-06-01

    Gas-phase dehydration of lactic acid (LA) to acrylic acid (AA) was investigated over alkali-exchanged β zeolite (M(x)Na(1-x)β, M=Li(+), K(+), Rb(+), or Cs(+)) of different exchange degrees (x). The reaction was conducted under varying conditions to understand the catalyst selectivity for AA production and trends of byproduct formation. The nature and exchange degree of M(+) were found to be critical for the acid-base properties and catalytic performance of the exchanged zeolite. K(x)Na(1-x)β of x=0.94 appeared to be the best performing catalyst whereas Li(x)Na(1-x)β and Naβ were the poorest in terms of AA selectivity and yield. The AA yield as high as 61 mol % (selectivity: 64 mol %) could be obtained under optimized reaction conditions for up to 8 h over the best performing K0.94Na0.06β. The acid and base properties of the catalysts were probed, respectively by temperature-programmed desorption (TPD) of adsorbed NH3 and CO2, and were related to the electrostatic potentials of the alkali ions in the zeolite, which provided a basis for the discussion of the acid-base catalysis for sustainable AA formation from LA.

  18. Oleanolic acid acrylate elicits antidepressant-like effect mediated by 5-HT1A receptor.

    PubMed

    Fajemiroye, James O; Polepally, Prabhakar R; Chaurasiya, Narayan D; Tekwani, Babu L; Zjawiony, Jordan K; Costa, Elson A

    2015-01-01

    The development of new drugs for the treatment of depression is strategic to achieving clinical needs of patients. This study evaluates antidepressant-like effect and neural mechanisms of four oleanolic acid derivatives i.e. acrylate (D1), methacrylate (D2), methyl fumarate (D3) and ethyl fumarate (D4). All derivatives were obtained by simple one-step esterification of oleanolic acid prior to pharmacological screening in the forced swimming (FS) and open field (OF) tests. Pharmacological tools like α-methyl-p-tyrosine (AMPT, catecholamine depletor), p-chlorophenylalanine (serotonin depletor), prazosin (PRAZ, selective α1-receptor antagonist), WAY-100635 (selective serotonin 5-HT1A receptor antagonist) as well as monoamine oxidase (MAO) and functional binding assays were conducted to investigate possible neural mechanisms. In the FS test, D1 showed the most promising antidepressant-like effect without eliciting locomotor incoordination. Unlike group of mice pretreated with AMPT 100 mg/kg, PCPA 100 mg/kg or PRAZ 1 mg/kg, the effect of D1 was attenuated by WAY-100635 0.3 mg/kg pretreatment. D1 demonstrated moderate inhibition of MAO-A (IC50 = 48.848 ± 1.935 μM), potency (pEC50 = 6.1 ± 0.1) and intrinsic activity (E max = 26 ± 2.0%) on 5-HT1A receptor. In conclusion, our findings showed antidepressant-like effect of D1 and possible involvement of 5-HT1A receptor.

  19. Biocompatible and mucoadhesive bacterial cellulose-g-poly(acrylic acid) hydrogels for oral protein delivery.

    PubMed

    Ahmad, Naveed; Amin, Mohd Cairul Iqbal Mohd; Mahali, Shalela Mohd; Ismail, Ismanizan; Chuang, Victor Tuan Giam

    2014-11-01

    Stimuli-responsive bacterial cellulose-g-poly(acrylic acid) hydrogels were investigated for their potential use as an oral delivery system for proteins. These hydrogels were synthesized using electron beam irradiation without any cross-linking agents, thereby eliminating any potential toxic effects associated with cross-linkers. Bovine serum albumin (BSA), a model protein drug, was loaded into the hydrogels, and the release profile in simulated gastrointestinal fluids was investigated. Cumulative release of less than 10% in simulated gastric fluid (SGF) demonstrated the potential of these hydrogels to protect BSA from the acidic environment of the stomach. Subsequent conformational stability analyses of released BSA by SDS-PAGE, circular dichroism, and an esterase activity assay indicated that the structural integrity and bioactivity of BSA was maintained and preserved by the hydrogels. Furthermore, an increase in BSA penetration across intestinal mucosa tissue was observed in an ex vivo penetration experiment. Our fabricated hydrogels exhibited excellent cytocompatibility and showed no sign of toxicity, indicating the safety of these hydrogels for in vivo applications.

  20. Synthesis, characterization, and swelling behaviors of salt-sensitive maize bran-poly(acrylic acid) superabsorbent hydrogel.

    PubMed

    Zhang, Mingyue; Cheng, Zhiqiang; Zhao, Tianqi; Liu, Mengzhu; Hu, Meijuan; Li, Junfeng

    2014-09-01

    A novel composite hydrogel was prepared via UV irradiation copolymerization of acrylic acid and maize bran (MB) in the presence of composite initiator (2,2-dimethoxy-2-phenylacetophenone and ammonium persulfate) and cross-linker (N,N'-methylenebis(acrylamide)). Under the optimized conditions, maize bran-poly(acrylic acid) was obtained (2507 g g(-1) in distilled water and 658 g g(-1) in 0.9 wt % NaCl solution). Effects of granularity, salt concentration, and various cations and anions on water absorbency were investigated. It was found that swelling was extremely sensitive to the ionic strength and cation and anion type. Swelling kinetics and water diffusion mechanism in distilled water were also discussed. Moreover, the product showed excellent water retention capability under the condition of high temperature or high pressure. The salt sensitivity, good water absorbency, and excellent water retention capability of the hydrogels give this intelligentized polymer wide potential applications.

  1. Synthesis, characterization, and swelling behaviors of salt-sensitive maize bran-poly(acrylic acid) superabsorbent hydrogel.

    PubMed

    Zhang, Mingyue; Cheng, Zhiqiang; Zhao, Tianqi; Liu, Mengzhu; Hu, Meijuan; Li, Junfeng

    2014-09-01

    A novel composite hydrogel was prepared via UV irradiation copolymerization of acrylic acid and maize bran (MB) in the presence of composite initiator (2,2-dimethoxy-2-phenylacetophenone and ammonium persulfate) and cross-linker (N,N'-methylenebis(acrylamide)). Under the optimized conditions, maize bran-poly(acrylic acid) was obtained (2507 g g(-1) in distilled water and 658 g g(-1) in 0.9 wt % NaCl solution). Effects of granularity, salt concentration, and various cations and anions on water absorbency were investigated. It was found that swelling was extremely sensitive to the ionic strength and cation and anion type. Swelling kinetics and water diffusion mechanism in distilled water were also discussed. Moreover, the product showed excellent water retention capability under the condition of high temperature or high pressure. The salt sensitivity, good water absorbency, and excellent water retention capability of the hydrogels give this intelligentized polymer wide potential applications. PMID:25133321

  2. Preparation, characterization, and antibacterial activity studies of silver-loaded poly(styrene-co-acrylic acid) nanocomposites.

    PubMed

    Song, Cunfeng; Chang, Ying; Cheng, Ling; Xu, Yiting; Chen, Xiaoling; Zhang, Long; Zhong, Lina; Dai, Lizong

    2014-03-01

    A simple method for preparing a new type of stable antibacterial agent was presented. Monodisperse poly(styrene-co-acrylic acid) (PSA) nanospheres, serving as matrices, were synthesized via soap-free emulsion polymerization. Field-emission scanning electron microscopy micrographs indicated that PSA nanospheres have interesting surface microstructures and well-controlled particle size distributions. Silver-loaded poly(styrene-co-acrylic acid) (PSA/Ag-NPs) nanocomposites were prepared in situ through interfacial reduction of silver nitrate with sodium borohydride, and further characterized by transmission electron microscopy and X-ray diffraction. Their effects on antibacterial activity including inhibition zone, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and bactericidal kinetics were evaluated. In the tests, PSA/Ag-NPs nanocomposites showed excellent antibacterial activity against both gram-positive Staphylococcus aureus and gram-negative Escherichia coli. These nanocomposites are considered to have potential application in antibacterial coatings on biomedical devices to reduce nosocomial infection rates. PMID:24433897

  3. A Novel Approach for the Desalination of Seawater by Means of Reusable Poly(acrylic acid) Hydrogels and Mechanical Force.

    PubMed

    Höpfner, Johannes; Klein, Christopher; Wilhelm, Manfred

    2010-08-01

    Desalination of a sodium chloride solution is achieved by the incorporation of salt depleted water into an acrylic acid based hydrogel and the subsequent deswelling of the gel by mechanical force to gain water with a lower salt content. This is a new approach towards the problem of desalination of seawater that has, to the best of our knowledge, not been presented before. In a proof-of-principle experiment the salt content of a 10 g/L NaCl solution could be reduced by 35% in one cycle. The influence of main chemical parameters, e.g. degree of crosslinking, degree of neutralization and experimental parameters like particle size and salt concentration on the desalination process are examined. Possible optimum conditions for the desalination using a poly(acrylic acid) network are discussed and the construction of a simple apparatus for deswelling by mechanical force is described.

  4. Lactic acid conversion to 2,3-pentanedione and acrylic acid over silica-supported sodium nitrate: Reaction optimization and identification of sodium lactate as the active catalyst

    SciTech Connect

    Wadley, D.C.; Tam, M.S.; Miller, D.J.

    1997-01-15

    Lactic acid is converted to 2,3-pentanedione, acrylic acid, and other products in vapor-phase reactions over silica-supported sodium lactate formed from sodium nitrate. Multiparameter optimization of reaction conditions using a Box-Benkhen experimental design shows that the highest yield and selectivity to 2,3-pentanedione are achieved at low temperature, elevated pressure, and long contact time, while yield and selectivity to acrylic acid are most favorable at high temperature, low pressure, and short contact time. Post-reaction Fourier transform infrared spectroscopic analyses of the catalyst indicate that sodium nitrate as the initial catalyst material is transformed to sodium lactate at the onset of reaction via proton transfer from lactic acid to nitrate. The resultant nitric acid vaporizes as it is formed, leaving sodium lactate as the sole sodium-bearing species on the catalyst during reaction. 19 refs., 8 figs., 5 tabs.

  5. Frequency-dependent magnetic susceptibility of magnetite and cobalt ferrite nanoparticles embedded in PAA hydrogel.

    PubMed

    van Berkum, Susanne; Dee, Joris T; Philipse, Albert P; Erné, Ben H

    2013-05-14

    Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here, acrylic acid monomers are adsorbed onto ferrite nanoparticles, which subsequently participate in polymerization during synthesis of poly(acrylic acid)-based hydrogels (PAA). To demonstrate the fixation of the nanoparticles to the polymer, our original approach is to measure low-field AC magnetic susceptibility spectra in the 0.1 Hz to 1 MHz range. In the hydrogel, the magnetization dynamics of small iron oxide nanoparticles are comparable to those of the particles dispersed in a liquid, due to fast Néel relaxation inside the particles; this renders the ferrogel useful for chemical sensing at frequencies of several kHz. However, ferrogels holding thermally blocked iron oxide or cobalt ferrite nanoparticles show significant decrease of the magnetic susceptibility resulting from a frozen magnetic structure. This confirms that the nanoparticles are unable to rotate thermally inside the hydrogel, in agreement with their irreversible fixation to the polymer network.

  6. Frequency-Dependent Magnetic Susceptibility of Magnetite and Cobalt Ferrite Nanoparticles Embedded in PAA Hydrogel

    PubMed Central

    van Berkum, Susanne; Dee, Joris T.; Philipse, Albert P.; Erné, Ben H.

    2013-01-01

    Chemically responsive hydrogels with embedded magnetic nanoparticles are of interest for biosensors that magnetically detect chemical changes. A crucial point is the irreversible linkage of nanoparticles to the hydrogel network, preventing loss of nanoparticles upon repeated swelling and shrinking of the gel. Here, acrylic acid monomers are adsorbed onto ferrite nanoparticles, which subsequently participate in polymerization during synthesis of poly(acrylic acid)-based hydrogels (PAA). To demonstrate the fixation of the nanoparticles to the polymer, our original approach is to measure low-field AC magnetic susceptibility spectra in the 0.1 Hz to 1 MHz range. In the hydrogel, the magnetization dynamics of small iron oxide nanoparticles are comparable to those of the particles dispersed in a liquid, due to fast Néel relaxation inside the particles; this renders the ferrogel useful for chemical sensing at frequencies of several kHz. However, ferrogels holding thermally blocked iron oxide or cobalt ferrite nanoparticles show significant decrease of the magnetic susceptibility resulting from a frozen magnetic structure. This confirms that the nanoparticles are unable to rotate thermally inside the hydrogel, in agreement with their irreversible fixation to the polymer network. PMID:23673482

  7. A novel poly(acrylic acid-co-acrylamide)/diatomite composite flocculant with outstanding flocculation performance.

    PubMed

    Xu, Kun; Liu, Yao; Wang, Yang; Tan, Ying; Liang, Xuecheng; Lu, Cuige; Wang, Haiwei; Liu, Xiusheng; Wang, Pixin

    2015-01-01

    Series of anionic flocculants with outstanding flocculation performance, poly(acrylic acid-co-acrylamide)/diatomite composite flocculants (PAAD) were successfully prepared through aqueous solution copolymerization and applied to flocculate from oil-field fracturing waste-water. The structure of PAAD was characterized by Fourier transform infra-red spectroscopy, (13)C nuclear magnetic resonance and X-ray diffraction tests, and its properties were systematically evaluated by viscometer, thermogravimetry analysis and flocculation measurements. Furthermore, the influences of various reaction parameters on the apparent viscosity of flocculant solution were studied, and the optimum synthesis condition was determined. The novel composite flocculants exhibited outstanding flocculation properties. Specifically, the dosage of composite flocculants that could make the transmittance of treated wastewater exceed 90% was only approximately 12-35 ppm, which was far lower than that of conventional flocculants. Meanwhile, the settling time was lower than 5 s, which was similar to that of conventional flocculants. This was because PAAD flocculants had a higher absorption capacity, and larger chain extending space than conventional linear flocculants, which could refrain from the entanglement of linear polymer chains and significantly improve flocculation capacity. PMID:26360748

  8. Synthesis and Biomedical Applications of Poly((meth)acrylic acid) Brushes.

    PubMed

    Qu, Zhenyuan; Xu, Hong; Gu, Hongchen

    2015-07-15

    Poly((meth)acrylic acid) (P(M)AA) brushes possess a number of distinctive properties that are particularly attractive for biomedical applications. This minireview summarizes recent advances in the synthesis and biomedical applications of P(M)AA brushes and brushes containing P(M)AA segments. First, we review different surface-initiated polymerization (SIP) methods, with a focus on recent progress in the surface-initiated controlled/living radical polymerization (SI-CLRP) techniques used to generate P(M)AA brushes with a tailored structure. Next, we discuss biomolecule immobilization methods for P(M)AA brushes, including physical adsorption, covalent binding, and affinity interactions. Finally, typical biomedical applications of P(M)AA brushes are reviewed, and their performance is discussed based on their unique properties. We conclude that P(M)AA brushes are promising biomaterials, and more potential biomedical applications are expected to emerge with the further development of synthetic techniques and increased understanding of their interactions with biological systems.

  9. Removal of cationic dyes by poly(acrylamide-co-acrylic acid) hydrogels in aqueous solutions

    NASA Astrophysics Data System (ADS)

    Şolpan, Dilek; Duran, Sibel; Torun, Murat

    2008-04-01

    Poly(acrylamide-co-acrylic acid (poly(AAm-co-AAc)) hydrogels prepared by irradiating with γ-radiation were used in experiments on swelling, diffusion, and uptake of some cationic dyes such as Safranine-O (SO) and Magenta (M). Poly(AAm-co-AAc) hydrogels irradiated at 8.0 kGy have been used for swelling and diffusion studies in water and cationic dye solutions. The maximum swellings in water, and SO, and M solutions observed are 2700%, 3500%, and 4000%, respectively. Diffusions of water and cationic dyes within hydrogels have been found to be non-Fickian in character. Adsorption of the cationic dyes onto poly(AAm-co-AAc) hydrogels is studied by the batch adsorption technique. The adsorption type was found Langmuir type in the Giles classification system. The moles of adsorbed dye for SO and M per repeating unit in hydrogel (binding ratio, r) have been calculated as 3834×10 -6 and 1323×10 -6, respectively. These results show that poly(AAm-co-AAc) hydrogels can be used as adsorbent for water pollutants such as cationic dyes.

  10. Potassium fulvate as co-interpenetrating agent during graft polymerization of acrylic acid from cellulose.

    PubMed

    Ghazy, Mohamed B M; El-Hai, Farag Abd; Mohamed, Magdy F; Essawy, Hisham A

    2016-10-01

    Grafting polymerization of acrylic acid onto cellulose in presence of potassium fulvate (KF) as a co-interpenetrating agent results enhanced water sorption compared to materials prepared similarly in its absence. The insertion of potassium fulvate (KF) did not affect the grafting process and is thought to proceed in parallel to the graft polymerization via intensive polycondensation reactions of its function groups (-COOH and OH) with COOH of the monomer and OH groups of cellulose. The combination of graft copolymerization and polycondensation reactions is assumed to produce interpenetrating network structure. Fourier transform infrared (FTIR) confirmed successful incorporation within the network structure which is an evidence for formation of interpenetrating network. The obtained structures showed homogeneous uniform surface as revealed by scanning electron microscopy (SEM). The obtained superabsorbent possessed high water absorbency 422 and 48.8g/g in distilled water and saline (0.9wt.% NaCl solution), respectively, and enhanced water retention even at elevated temperatures as revealed by thermogravimetric analysis (TGA). This could be explained by the high content of hydrophilic groups. The new superabsorbents proved to be efficient devices for controlled release of fertilizers which expands their use in agricultural applications. PMID:27370745

  11. A novel poly(acrylic acid-co-acrylamide)/diatomite composite flocculant with outstanding flocculation performance.

    PubMed

    Xu, Kun; Liu, Yao; Wang, Yang; Tan, Ying; Liang, Xuecheng; Lu, Cuige; Wang, Haiwei; Liu, Xiusheng; Wang, Pixin

    2015-01-01

    Series of anionic flocculants with outstanding flocculation performance, poly(acrylic acid-co-acrylamide)/diatomite composite flocculants (PAAD) were successfully prepared through aqueous solution copolymerization and applied to flocculate from oil-field fracturing waste-water. The structure of PAAD was characterized by Fourier transform infra-red spectroscopy, (13)C nuclear magnetic resonance and X-ray diffraction tests, and its properties were systematically evaluated by viscometer, thermogravimetry analysis and flocculation measurements. Furthermore, the influences of various reaction parameters on the apparent viscosity of flocculant solution were studied, and the optimum synthesis condition was determined. The novel composite flocculants exhibited outstanding flocculation properties. Specifically, the dosage of composite flocculants that could make the transmittance of treated wastewater exceed 90% was only approximately 12-35 ppm, which was far lower than that of conventional flocculants. Meanwhile, the settling time was lower than 5 s, which was similar to that of conventional flocculants. This was because PAAD flocculants had a higher absorption capacity, and larger chain extending space than conventional linear flocculants, which could refrain from the entanglement of linear polymer chains and significantly improve flocculation capacity.

  12. Synthesis, structure and phase transition property of acrylic acid grafted paraffin

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaowen; Liu, Pengfei; Ye, Lin

    2014-05-01

    Polar monomer acrylic acid (AA) was used to modify paraffin in order to improve the latent heat of paraffin as phase change materials. The composition and sequence structure of the grafted products were characterized by FTIR, 13C NMR, 1H NMR and GPC analysis, and the thermal properties of paraffin-g-AA were investigated. It was found that AA was confirmed to be grafted onto the molecular chain of paraffin successfully. The mechanism of free radical grafting of AA may be only monomeric grafts. At low grafting ratio, the structure B can be mainly formed as a result of the radical coupling termination; while at the high grafting ratio, structure A was the primary structure as a result of the radical chain growth process. The number-average molecular weight of the grafted samples increased at first but leveled off with increasing grafting ratio, while the weight-average molecular weight increased gradually. The latent heat capacity of the grafted paraffin can be improved obviously at low grafting ratio due to the formation of structure B.

  13. Surfactants modify the release from tablets made of hydrophobically modified poly (acrylic acid).

    PubMed

    Knöös, Patrik; Onder, Sebla; Pedersen, Lina; Piculell, Lennart; Ulvenlund, Stefan; Wahlgren, Marie

    2013-01-01

    Many novel pharmaceutically active substances are characterized by a high hydrophobicity and a low water solubility, which present challenges for their delivery as drugs. Tablets made from cross-linked hydrophobically modified poly (acrylic acid) (CLHMPAA), commercially available as Pemulen™, have previously shown promising abilities to control the release of hydrophobic model substances. This study further investigates the possibility to use CLHMPAA in tablet formulations using ibuprofen as a model substance. Furthermore, surfactants were added to the dissolution medium in order to simulate the presence of bile salts in the intestine. The release of ibuprofen is strongly affected by the presence of surfactant and/or buffer in the dissolution medium, which affect both the behaviour of CLHMPAA and the swelling of the gel layer that surrounds the disintegrating tablets. Two mechanisms of tablet disintegration were observed under shear, namely conventional dissolution of a soluble tablet matrix and erosion of swollen insoluble gel particles from the tablet. The effects of surfactant in the surrounding medium can be circumvented by addition of surfactant to the tablet. With added surfactant, tablets that may be insusceptible to the differences in bile salt level between fasted or fed states have been produced, thus addressing a central problem in controlled delivery of hydrophobic drugs. In other words CLHMPAA is a potential candidate to be used in tablet formulations for controlled release with poorly soluble drugs.

  14. Preparation and adsorption property of xylan/poly(acrylic acid) magnetic nanocomposite hydrogel adsorbent.

    PubMed

    Sun, Xiao-Feng; Liu, Baichen; Jing, Zhanxin; Wang, Haihong

    2015-03-15

    Adsorbents based on natural polysaccharides have attracted increasing interest because of their low-cost and biodegradability, particularly, polysaccharide-based nanocomposite adsorbents. In this study the xylan/poly(acrylic acid) magnetic nanocomposite hydrogel adsorbent was prepared from wheat straw xylan and Fe3O4 nanoparticles, and its adsorption property was studied on methylene blue removal. The prepared hydrogel adsorbent had a semi-interpenetrating network structure and exhibited a macro-porous structure with interconnected porous channels. Super-paramagnetic characteristic behavior was observed from magnetic analysis using a vibrating sample magnetometer. The optimum condition for methylene blue adsorption on the adsorbent was found at pH 8 with an adsorbent dosage of 3g/L and an initial concentration of 400mg/L, and the removal percentage reached above 90%. The adsorption isotherm of methylene blue on the prepared hydrogel adsorbent was fitted to the Langmuir model, and the pseudo-second-order kinetic model could describe the adsorption process. All obtained results indicated that the prepared hydrogel adsorbent is promising for water treatment applications. PMID:25542101

  15. Graft polymerization of acrylic acid and methacrylic acid onto poly(vinylidene fluoride) powder in presence of metallic salt and sulfuric acid

    NASA Astrophysics Data System (ADS)

    Deng, Bo; Yu, Yang; Zhang, Bowu; Yang, Xuanxuan; Li, Linfan; Yu, Ming; Li, Jingye

    2011-02-01

    Poly(vinylidene fluoride) (PVDF) powder was grafted with acrylic acid (AAc) or methacrylic acid (MAA) by the pre-irradiation induced graft polymerization technique. The presence of graft chains was proven by FT-IR spectroscopy. The degree of grafting (DG) was calculated by the acid-base back titration method. The synergistic effect of acid and Mohr's salt on the grafting kinetics was examined. The results indicated that adding sulfuric acid and Mohr's salt simultaneously in AAc or MAA solutions led to a strong enhancement in the degree of grafting. The grafted PVDF powder was cast into microfiltration (MF) membranes using the phase inversion method and some properties of the obtained MF membranes were characterized.

  16. A study on the effect of the concentration of N,N-methylenebisacrylamide and acrylic acid toward the properties of Dioscorea hispida-starch-based hydrogel

    NASA Astrophysics Data System (ADS)

    Ashri, Airul; Lazim, Azwan

    2014-09-01

    The research investigated the effects of acrylic acid (monomer) and N,N,-methylenebisacrylamide, MBA (crosslinker) toward the percentage of gel content, swelling ratio and ionic strength of a starch-based hydrogel. Starch grafted on poly (sodium acrylate), St-g-PAANa hydrogel was prepared by incorporating starch extracted from Dioscorea hispida in NaOH/aqueous solution using different composition of acrylic acid (AA) and N,N-methylenebisacrylamide (MBA) in the presence of potassium persulfate (KPS) as chemical initiator. The highest gel content was observed at 1:30 ratio of starch to AA and 0.10 M of MBA. Results showed the highest swelling ratio was observed at 1:15 ratio of starch to acrylic acid and 0.02 M of MBA solution. The same results also gave the highest swelling ratio for the ionic strength study. The FTIR analysis was also conducted in order to confirm the grafting of AA onto starch backbone.

  17. Oleanolic acid acrylate elicits antidepressant-like effect mediated by 5-HT1A receptor

    PubMed Central

    Fajemiroye, James O.; Polepally, Prabhakar R.; Chaurasiya, Narayan D.; Tekwani, Babu L.; Zjawiony, Jordan K.; Costa, Elson A.

    2015-01-01

    The development of new drugs for the treatment of depression is strategic to achieving clinical needs of patients. This study evaluates antidepressant-like effect and neural mechanisms of four oleanolic acid derivatives i.e. acrylate (D1), methacrylate (D2), methyl fumarate (D3) and ethyl fumarate (D4). All derivatives were obtained by simple one-step esterification of oleanolic acid prior to pharmacological screening in the forced swimming (FS) and open field (OF) tests. Pharmacological tools like α-methyl-p-tyrosine (AMPT, catecholamine depletor), p-chlorophenylalanine (serotonin depletor), prazosin (PRAZ, selective α1-receptor antagonist), WAY-100635 (selective serotonin 5-HT1A receptor antagonist) as well as monoamine oxidase (MAO) and functional binding assays were conducted to investigate possible neural mechanisms. In the FS test, D1 showed the most promising antidepressant-like effect without eliciting locomotor incoordination. Unlike group of mice pretreated with AMPT 100 mg/kg, PCPA 100 mg/kg or PRAZ 1 mg/kg, the effect of D1 was attenuated by WAY-100635 0.3 mg/kg pretreatment. D1 demonstrated moderate inhibition of MAO-A (IC50 = 48.848 ± 1.935 μM), potency (pEC50 = 6.1 ± 0.1) and intrinsic activity (Emax = 26 ± 2.0%) on 5-HT1A receptor. In conclusion, our findings showed antidepressant-like effect of D1 and possible involvement of 5-HT1A receptor. PMID:26199018

  18. The C-F...F-C short contacts in the metal complexes of fluoro-phenyl-acrylic acids

    SciTech Connect

    Liu Guilei; Liu CaiMing; Li Hui

    2011-03-15

    Four new complexes of fluoro-phenyl-acrylic acids (E)-3-(3-fluoro-phenyl)-acrylic acid (L1) [Mn{sub 3}(L1){sub 6}(L2){sub 2}].H{sub 2}O.CH{sub 3}CN (1), [Zn{sub 2}(L1){sub 4}(L3)]{sub n} (2), [Mn(L1){sub 2}(H{sub 2}O){sub 2}]{sub n} (3) and [Co(L1){sub 2}(H{sub 2}O){sub 2}]{sub n} (4) (L2=1,10-phenanthroline, L3=4,4'-bipy) have been synthesized based on the molecular design and research of halogen-halogen interactions (especially fluoro-fluoro contact). The structure analyses reveal that complex 1 is a trinuclear complex, which is blocked by L2. Complex 2 is a 1D chain bridged through L3. Complexes 3 and 4 exhibit 2D grid like metal-organic framework structures through carboxylato bridge ligand. Variable-temperature magnetic measurements showed an antiferromagnetic interaction between Mn(II) ions and between Co(II) ions in complexes 3 and 4, respectively. A short C-F...F-C contact with a distance of 2.953 A was found between the trinuclear coordination compound 1. -- Graphical Abstract: The short distance between F...F (2.953 A) was found in the complex of [Mn{sub 3}(L1){sub 6}(L2){sub 2}].H{sub 2}O.CH{sub 3}CN (L1=(E)-3-(3-fluoro-phenyl)-acrylic acid, L2=1,-10-phenanthroline). Display Omitted Research highlights: > Four new complexes of fluoro-phenyl-acrylic acids (E)-3-(3-fluoro-phenyl)-acrylic acid (L1) [Mn{sub 3}(L1){sub 6}(L2){sub 2}].H{sub 2}O.CH{sub 3}CN (1), [Zn{sub 2}(L1){sub 4}(L3)]{sub n} (2), [Mn(L1){sub 2}(H{sub 2}O){sub 2}]{sub n} (3) and [Co(L1){sub 2}(H{sub 2}O){sub 2}]{sub n} (4) (L2=1,10-phenanthroline, L3=4,4'-bipy) have been synthesized based on the molecular design and research of halogen-halogen interactions (especially fluoro-fluoro contact). > A short C-F...F-C contact with a distance of 2.953 A was found between the trinuclear coordination compound 1. > Variable-temperature magnetic measurements showed an antiferromagnetic interaction between Mn(II) ions and between Co(II) ions in complexes 3 and 4, respectively.

  19. Production of dimethylsulfide and acrylic acid from dimethylsulfoniopropionate during growth of three marine microalgae

    NASA Astrophysics Data System (ADS)

    Liu, Chunying; Gao, Caixia; Zhang, Haibo; Chen, Shuo; Deng, Ping; Yue, Xin'an; Guo, Xiaoyi

    2014-11-01

    We measured the concentrations of dimethylsulfide (DMS), acrylic acid (AA), and dimethylsulfoniopropionate (DMSP) during growth of three microalgae: Prorocentrum micans, Gephyrocapsa oceanica, and Platymonas subcordiformis. The DMSP, AA, and DMS concentrations in culture media varied significantly among algal growth stages, with the highest concentrations in the late stationary growth stage or the senescent stage. In the stationary growth stage, the average DMSP concentration per cell in P. micans (0.066 5 pmol/cell) was 1.3 times that in G. oceanica (0.049 5 pmol/cell) and 20.2 times that in P. subcordiformis (0.003 29 pmol/cell). The average concentrations of AA were 0.044 6, 0.026 9, and 0.003 05 pmol/cell in P. micans, G. oceanica, and P. subcordiformi s, respectively, higher than the concentrations of DMS (0.272, 0.497, and 0.086 2 fmol/cell, respectively). There were significant positive correlations between cell density and AA, DMSP, and DMS concentrations. The ratios of DMS/AA and AA/(DMSP+AA) in the three algae differed significantly over the growth cycle. In all three microalgae, the DMS/AA ratios were less than 25% during the growth period, suggesting that the enzymatic cleavage pathway, which generates DMS, was not the main DMSP degradation pathway. The changes in the DMS/AA ratio indicated that there was a higher rate of enzymatic breakdown of DMSP in the early growth period and a lower rate during senescence. In all three microalgae, the AA/(DMSP+AA) ratio (degradation ratio of DMSP) decreased during the exponential growth phase, and then increased. The variations in these ratios can approximately indicate the cleavage mechanism of DMSP at different stages of algal growth.

  20. Production of dimethylsulfide and acrylic acid from dimethylsulfoniopropionate during growth of three marine microalgae

    NASA Astrophysics Data System (ADS)

    Liu, Chunying; Gao, Caixia; Zhang, Haibo; Chen, Shuo; Deng, Ping; Yue, Xin'an; Guo, Xiaoyi

    2014-07-01

    We measured the concentrations of dimethylsulfide (DMS), acrylic acid (AA), and dimethylsulfoniopropionate (DMSP) during growth of three microalgae: Prorocentrum micans, Gephyrocapsa oceanica, and Platymonas subcordiformis. The DMSP, AA, and DMS concentrations in culture media varied significantly among algal growth stages, with the highest concentrations in the late stationary growth stage or the senescent stage. In the stationary growth stage, the average DMSP concentration per cell in P. mican s (0.066 5 pmol/cell) was 1.3 times that in G. oceanica (0.049 5 pmol/cell) and 20.2 times that in P. subcordiformi s (0.003 29 pmol/cell). The average concentrations of AA were 0.044 6, 0.026 9, and 0.003 05 pmol/cell in P. micans, G. oceanica, and P. subcordiformi s, respectively, higher than the concentrations of DMS (0.272, 0.497, and 0.086 2 fmol/cell, respectively). There were significant positive correlations between cell density and AA, DMSP, and DMS concentrations. The ratios of DMS /AA and AA /(DMSP+AA) in the three algae differed significantly over the growth cycle. In all three microalgae, the DMS/AA ratios were less than 25% during the growth period, suggesting that the enzymatic cleavage pathway, which generates DMS, was not the main DMSP degradation pathway. The changes in the DMS/AA ratio indicated that there was a higher rate of enzymatic breakdown of DMSP in the early growth period and a lower rate during senescence. In all three microalgae, the AA /(DMSP+AA) ratio (degradation ratio of DMSP) decreased during the exponential growth phase, and then increased. The variations in these ratios can approximately indicate the cleavage mechanism of DMSP at different stages of algal growth.

  1. Low Light CMOS Contact Imager with an Integrated Poly-Acrylic Emission Filter for Fluorescence Detection

    PubMed Central

    Dattner, Yonathan; Yadid-Pecht, Orly

    2010-01-01

    This study presents the fabrication of a low cost poly-acrylic acid (PAA) based emission filter integrated with a low light CMOS contact imager for fluorescence detection. The process involves the use of PAA as an adhesive for the emission filter. The poly-acrylic solution was chosen due its optical transparent properties, adhesive properties, miscibility with polar protic solvents and most importantly its bio-compatibility with a biological environment. The emission filter, also known as an absorption filter, involves dissolving an absorbing specimen in a polar protic solvent and mixing it with the PAA to uniformly bond the absorbing specimen and harden the filter. The PAA is optically transparent in solid form and therefore does not contribute to the absorbance of light in the visible spectrum. Many combinations of absorbing specimen and polar protic solvents can be derived, yielding different filter characteristics in different parts of the spectrum. We report a specific combination as a first example of implementation of our technology. The filter reported has excitation in the green spectrum and emission in the red spectrum, utilizing the increased quantum efficiency of the photo sensitive sensor array. The thickness of the filter (20 μm) was chosen by calculating the desired SNR using Beer-Lambert’s law for liquids, Quantum Yield of the fluorophore and the Quantum Efficiency of the sensor array. The filters promising characteristics make it suitable for low light fluorescence detection. The filter was integrated with a fully functional low noise, low light CMOS contact imager and experimental results using fluorescence polystyrene micro-spheres are presented. PMID:22399920

  2. Synthesis and physicochemical properties of organofluorine esters of acrylic, methacrylic, and maleic acids

    SciTech Connect

    Gol'din, G.S.; Averbakh, K.O.; Lavygin, I.A.; Nekrasova, L.A.

    1985-12-01

    The authors synthesize and study the physicochemical properties of organofluorine acrylates, methacrylates, and maleates. The organofluorine esters are colorless liquids; their composition and structure were confirmed by elemental analysis and IR spectra. The results of studies of the dependence of the density, surface tension, and viscosity of these compounds on temperature are presented. The results revealed the influence of the length of the fluorocarbon chain on the combination of the physicochemical properties of organofluorine acrylates, methacrylates, and maleates, and also provided a method for estimating certain thermophysical characteristics of such compounds without recourse to experimental measurements.

  3. SYNTHESIS AND IN VITRO CHARACTERIZATION OF HYDROXYPROPYL METHYLCELLULOSE-GRAFT-POLY (ACRYLIC ACID/2-ACRYLAMIDO-2-METHYL-1-PROPANESULFONIC ACID) POLYMERIC NETWORK FOR CONTROLLED RELEASE OF CAPTOPRIL.

    PubMed

    Furqan Muhammad, Iqbal; Mahmood, Ahmad; Aysha, Rashid

    2016-01-01

    A super-absorbent hydrogel was developed by crosslinking of 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) and acrylic acid with hydroxypropyl methylcellulose (HPMC) for controlled release drug delivery of captopril, a well known antihypertensive drug. Acrylic acid and AMPS were polymerized and crosslinked with HPMC by free radical polymerization, a widely used chemical crosslinking method. N,N'-methylenebisacrylamide (MBA) and potassium persulfate (KPS) were added as cross-linker and initiator, respectively. The hydrogel formulation was loaded with captopril (as model drug). The concentration of captopril was monitored at 205 nm using UV spectrophotometer. Equilibrium swelling ratio was determined at pH 2, 4.5 and 7.4 to evaluate the pH responsiveness of the formed hydrogel. The super-absorbent hydrogels were evaluated by FTIR, SEM, XRD, and thermal analysis (DSC and TGA). The formation of new copolymeric network was determined by FTIR, XRD, TGA and DSC analysis. The hydrogel formulations with acrylic acid and AMPS ratio of 4: 1 and lower amounts of crosslinker had shown maximum swelling. Moreover, higher release rate of captopril was observed at pH 7.4 than at pH 2, because of more swelling capacity of copolymer with increasing pH of the aqueous medium. The present research work confirms the development of a stable hydrogel comprising of HPMC with acrylic acid and AMPS. The prepared hydrogels exhibited pH sensitive behav-ior. This superabsorbent composite prepared could be a successful drug carrier for treating hypertension. PMID:27008813

  4. Tuning of thermally induced sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid).

    PubMed

    Jin, Naixiong; Zhang, Hao; Jin, Shi; Dadmun, Mark D; Zhao, Bin

    2012-03-15

    We report in this article a method to tune the sol-to-gel transitions of moderately concentrated aqueous solutions of doubly thermosensitive hydrophilic diblock copolymers that consist of two blocks exhibiting distinct lower critical solution temperatures (LCSTs) in water. A small amount of weak acid groups is statistically incorporated into the lower LCST block so that its LCST can be tuned by varying solution pH. Well-defined diblock copolymers, poly(methoxytri(ethylene glycol) acrylate)-b-poly(ethoxydi(ethylene glycol) acrylate-co-acrylic acid) (PTEGMA-b-P(DEGEA-co-AA)), were prepared by reversible addition-fragmentation chain transfer polymerization and postpolymerization modification. PTEGMA and PDEGEA are thermosensitive water-soluble polymers with LCSTs of 58 and 9 °C, respectively, in water. A 25 wt % aqueous solution of PTEGMA-b-P(DEGEA-co-AA) with a molar ratio of DEGEA to AA units of 100:5.2 at pH = 3.24 underwent multiple phase transitions upon heating, from a clear, free-flowing liquid (<15 °C) to a clear, free-standing gel (15-46 °C) to a clear, free-flowing hot liquid (47-56 °C), and a cloudy mixture (≥57 °C). With the increase of pH, the sol-to-gel transition temperature (T(sol-gel)) shifted to higher values, while the gel-to-sol transition (T(gel-sol)) and the clouding temperature (T(clouding)) of the sample remained essentially the same. These transitions and the tunability of T(sol-gel) originated from the thermosensitive properties of two blocks of the diblock copolymer and the pH dependence of the LCST of P(DEGEA-co-AA), which were confirmed by dynamic light scattering and differential scanning calorimetry studies. Using the vial inversion test method, we mapped out the C-shaped sol-gel phase diagrams of the diblock copolymer in aqueous buffers in the moderate concentration range at three different pH values (3.24, 5.58, and 5.82, all measured at ~0 °C). While the upper temperature boundaries overlapped, the lower temperature boundary

  5. Highly efficient asymmetric hydrogenation of cyano-substituted acrylate esters for synthesis of chiral γ-lactams and amino acids.

    PubMed

    Kong, Duanyang; Li, Meina; Wang, Rui; Zi, Guofu; Hou, Guohua

    2016-01-28

    A highly efficient and enantioselective synthesis of γ-lactams and γ-amino acids by Rh-catalyzed asymmetric hydrogenation has been developed. Using the Rh-(S,S)-f-spiroPhos complex, under mild conditions a wide range of 3-cyano acrylate esters including both E and Z-isomers and β-cyano-α-aryl-α,β-unsaturated ketones were first hydrogenated with excellent enantioselectivities (up to 98% ee) and high turnover numbers (TON up to 10,000). PMID:26661067

  6. Molecularly imprinted films of acrylonitrile/methyl methacrylate/acrylic acid terpolymers: influence of methyl methacrylate in the binding performance of L-ephedrine imprinted films.

    PubMed

    Brisbane, Carrie; McCluskey, Adam; Bowyer, Michael; Holdsworth, Clovia I

    2013-05-01

    Molecularly imprinted polymeric films (MIPFs) highly selective to 1R,2S(-)ephedrine (L-ephedrine, EPD) were produced by phase inversion post-polymerization imprinting on poly(acrylonitrile-co-methyl methacrylate-co-acrylic acid) (PAMA) terpolymers. The inclusion of methyl methacrylate (MMA) to the polymer formulation resulted in enhanced EPD selectivity which appears to be dictated by polymer composition to achieve the necessary balance between polymer rigidity and porosity. Substitution of MMA with methyl acrylate, ethyl acrylate and n-butyl acrylate resulted in a loss of EPD selectivity and EPD entrapment within the polymer matrix not observed in PAMA MIPFs. MMA, by virtue of its methyl group, is able to provide the scaffolding and rigidity necessary for stability and preservation of imprinted cavities within the PAMA MIPF leading to high EPD selectivity.

  7. Investigations of PAA degradation in aqueous solutions: Impacts of water hardness, salinity and DOC

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is used in aquaculture under various conditions for disinfection purposes. However, there is lack of information about its environmental fate. Therefore, the impact of water hardness, salinity, and dissolved organic carbon (DOC) on PAA-degradation within 5 hours was investigat...

  8. Poly(ethylene glycol)-co-methacrylamide-co-acrylic acid based nanogels for delivery of doxorubicin.

    PubMed

    Kumar, Parveen; Behl, Gautam; Sikka, Manisha; Chhikara, Aruna; Chopra, Madhu

    2016-10-01

    Polymeric nanogels have been widely explored for their potential application as delivery carriers for cancer therapeutics. The ability of nanogels to encapsulate therapeutics by simple diffusion mechanism and the ease of their fabrication to impart target specificity in addition to their ability to get internalized into target cells make them good candidates for drug delivery. The present study aims to investigate the applicability of poly(ethylene glycol)-co-methacrylamide-co-acrylic acid (PMA)-based nanogels as a viable option for the delivery of doxorubicin (DOX). The nanogels were synthesized by free radical polymerization in an inverse mini-emulsion and characterized by nuclear magnetic resonance spectroscopy ((1)H NMR), Fourier transform infrared spectroscopy, dynamic light scattering, transmission electron microscopy (TEM), X-ray diffraction and differential scanning calorimetry. DOX was physically incorporated into the nanogels (PMA-DOX) and the mechanism of its in vitro release was studied. TEM experiment revealed spherical morphology of nanogels and the hydrodynamic diameter of the neat nanogels was in the range of 160 ± 46.95 nm. The size of the nanogels increased from 235.1 ± 28.46 to 403.7 ± 89.89 nm with the increase in drug loading capacity from 4.68 ± 0.03 to 13.71 ± 0.01%. The sustained release of DOX was observed upto 80 h and the release rate decreased with increased loading capacity following anomalous release mechanism as indicated by the value of diffusion exponent (n = 0.64-0.75) obtained from Korsmeyer-Peppas equation. Further, cytotoxicity evaluation of PMA-DOX nanogels on HeLa cells resulted in relatively higher efficacy (IC50~5.88 μg/mL) as compared to free DOX (IC50~7.24 μg/mL) thus demonstrating that the preparation is potentially a promising drug delivery carrier.

  9. Study of the influence of the acrylic acid plasma parameters on silicon and polyurethane substrates using XPS and AFM

    NASA Astrophysics Data System (ADS)

    Vilani, C.; Weibel, D. E.; Zamora, R. R. M.; Habert, A. C.; Achete, C. A.

    2007-10-01

    XPS and AFM have been used to investigate surface modifications produced by acrylic acid (AA) vapor plasma treatment of silicon (Si)(1 0 0) substrates and polyurethanes (PUs) membranes. XPS analyses of Si and PUs treated substrates at low plasma power (5-20 W) revealed the formation of a thin film on the surfaces, which chemically resembles the poly(acrylic acid) film conventionally synthesised. No signal of the Si substrate could be seen under these low plasma power applications on silicon. However, when the plasma power is higher than 30 W one can clearly see XPS silicon signatures. AFM measurements of silicon substrates treated with AA plasma at low power (5-20 W) showed the formation of a thin polymer film of about 220-55 nm thickness. Further, applications of high plasma power (30-100 W) displayed a marked difference from low plasma modifications and it was found sputtering of the silicon substrate. Pervaporation results of AA plasma treated PUs membranes revealed that the selectivity for the separation of methanol from methyl- t-butyl ether is higher at 100 W and 1 min treatment time, than the other conditions studied. This last finding is discussed concerning the surface modifications produced on plasma treated silicon substrates and PU membranes.

  10. Emission spectroscopy of the predissociative excited state dynamics of acrolein, acrylic acid, and acryloyl chloride at 199 nm

    SciTech Connect

    Arendt, M.F.; Browning, P.W.; Butler, L.J.

    1995-10-08

    The emission spectroscopy of acrolein (C{sub 3}H{sub 4}O), acrylic acid (C{sub 2}H{sub 3}COOH), and acryloyl chloride (C{sub 2}H{sub 3}COCl) excited at 199 nm elucidates the dominant electronic character of the excited state reached by the optical transition at this wavelength. Progressions in the C=C and C=O stretching overtones and various combination bands suggest the antibonding orbital has mixed {pi}*(C=C)/{pi}*(C=O) character. We interpret the results in conjunction with {ital ab} {ital initio} calculations at the configuration interaction singles level to identify the influence of resonance in the excited state of these conjugated molecules. The results on acrylic acid are of particular interest as excitation in this absorption band produces the HOCO intermediate of the OH+CO{r_arrow}H+CO{sub 2} reaction that is important in combustion. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  11. Water-soluble complexes of star-shaped poly(acrylic acid) with quaternized poly(4-vinylpyridine).

    PubMed

    Pergushov, Dmitry V; Babin, Ivan A; Plamper, Felix A; Zezin, Alexander B; Müller, Axel H E

    2008-06-01

    The interaction of star-shaped poly(acrylic acid) having various numbers of arms (5, 8, and 21) and a strong cationic polyelectrolyte, viz., poly( N-ethyl-4-vinylpyridinium bromide), was examined at pH 7 by means of turbidimetry and dynamic light scattering. Mixing aqueous solutions of the oppositely charged polymeric components was found to result in phase separation only if their base-molar ratio Z = [N+]/[COO (-) + COOH] exceeds a certain critical value ZM ( ZM < 1); this threshold value is determined by the number of arms of the star-shaped polyelectrolyte and the ionic strength of the surrounding solution. At Z < ZM, the homogeneous aqueous mixtures of the oppositely charged polymeric components contain two types of complex species clearly differing in their sizes, with the fractions of these species appearing to depend distinctly on the number of arms of the star-shaped poly(acrylic acid), the base-molar ratio of the oppositely charged polymeric components in their mixtures, and the ionic strength of the surrounding solution. The small complex species (major fraction) are assumed to represent the particles of the water-soluble interpolyelectrolyte complex whereas the large complex species (minor fraction) are considered to be complex aggregates.

  12. Developing the potential ophthalmic applications of pilocarpine entrapped into polyvinylpyrrolidone-poly(acrylic acid) nanogel dispersions prepared by γ radiation.

    PubMed

    Abd El-Rehim, Hassan A; Swilem, Ahmed E; Klingner, Anke; Hegazy, El-Sayed A; Hamed, Ashraf A

    2013-03-11

    The aim of this study was to improve the stability and bioavailability of pilocarpine in order to maintain an adequate concentration of the pilocarpine at the site of action for prolonged period of time. Thus, pH-sensitive polyvinylpyrrolidone-poly(acrylic acid) (PVP/PAAc) nanogels prepared by γ radiation-induced polymerization of acrylic acid (AAc) in an aqueous solution of polyvinylpyrrolidone (PVP) as a template polymer were used to encapsulate pilocarpine. Factors affecting size and encapsulation efficiency were optimized to obtain nanogel suitable for entrapping drug efficiently. The PVP/PAAc nanogel particles were characterized by dynamic light scattering (DLS), zeta potential, Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM), and their size can be controlled by the feed composition and concentration as well as the irradiation dose. Pilocarpine was loaded into the nanogel particles through electrostatic interactions where the AAc-rich nanogels exhibited the highest loading efficiency. The transmittance, mucoadhesion, and rheological characteristics of the nanogel particles were studied to evaluate their ocular applicability. The in vitro release study conducted in simulated tear fluid showed a relatively long sustained release of pilocarpine from the prepared PVP/PAAc nanogel particles if compared with pilocarpine in solution.

  13. Segregation of mass at the periphery of N -isopropylacrylamide-co-acrylic-acid microgels at high temperatures

    DOE PAGES

    Hyatt, John S.; Do, Changwoo; Hu, Xiaobo; Choi, Hong Sung; Kim, Jin Woong; Lyon, L. Andrew; Fernandez-Nieves, Alberto

    2015-09-29

    Here, we investigate poly(N-isopropylacrylamide) (pNIPAM) microgels randomly copolymerized with large mol % of protonated acrylic acid (AAc), finding that above the lower critical solution temperature the presence of the acid strongly disrupts pNIPAM's collapse, leading to unexpected new behavior at high temperatures. We see a dramatic increase in the ratio between the radius of gyration and the hydrodynamic radius above the theoretical value for homogeneous spheres, and a corresponding increase of the network length scale, which we attribute to the presence of a heterogeneous polymer distribution that forms due to frustration of pNIPAM's coil-to-globule transition by the AAc. Finally, wemore » analyze this phenomenon using a Debye-Bueche-like scattering contribution as opposed to the Lorentzian term often used, interpreting the results in terms of mass segregation at the particle periphery.« less

  14. Involvement of the TetR-Type Regulator PaaR in the Regulation of Pristinamycin I Biosynthesis through an Effect on Precursor Supply in Streptomyces pristinaespiralis

    PubMed Central

    Zhao, Yawei; Feng, Rongrong; Zheng, Guosong; Tian, Jinzhong; Ruan, Lijun; Ge, Mei; Jiang, Weihong

    2015-01-01

    ABSTRACT Pristinamycin I (PI), produced by Streptomyces pristinaespiralis, is a streptogramin type B antibiotic, which contains two proteinogenic and five aproteinogenic amino acid precursors. PI is coproduced with pristinamycin II (PII), a member of streptogramin type A antibiotics. The PI biosynthetic gene cluster has been cloned and characterized. However, thus far little is understood about the regulation of PI biosynthesis. In this study, a TetR family regulator (encoded by SSDG_03033) was identified as playing a positive role in PI biosynthesis. Its homologue, PaaR, from Corynebacterium glutamicum serves as a transcriptional repressor of the paa genes involved in phenylacetic acid (PAA) catabolism. Herein, we also designated the identified regulator as PaaR. Deletion of paaR led to an approximately 70% decrease in PI production but had little effect on PII biosynthesis. Identical to the function of its homologue from C. glutamicum, PaaR is also involved in the suppression of paa expression. Given that phenylacetyl coenzyme A (PA-CoA) is the common intermediate of the PAA catabolic pathway and the biosynthetic pathway of l-phenylglycine (l-Phg), the last amino acid precursor for PI biosynthesis, we proposed that derepression of the transcription of paa genes in a ΔpaaR mutant possibly diverts more PA-CoA to the PAA catabolic pathway, thereby with less PA-CoA metabolic flux toward l-Phg formation, thus resulting in lower PI titers. This hypothesis was verified by the observations that PI production of a ΔpaaR mutant was restored by l-Phg supplementation as well as by deletion of the paaABCDE operon in the ΔpaaR mutant. Altogether, this study provides new insights into the regulation of PI biosynthesis by S. pristinaespiralis. IMPORTANCE A better understanding of the regulation mechanisms for antibiotic biosynthesis will provide valuable clues for Streptomyces strain improvement. Herein, a TetR family regulator PaaR, which serves as the repressor of the

  15. Removal of Cu(II) and Ni(II) using cellulose extracted from sisal fiber and cellulose-g-acrylic acid copolymer.

    PubMed

    Hajeeth, T; Vijayalakshmi, K; Gomathi, T; Sudha, P N

    2013-11-01

    The extraction of cellulose from sisal fiber was done initially using the steam explosion method. The batch adsorption studies were conducted using the cellulose extracted from the sisal fiber and cellulose-g-acrylic acid as an adsorbent for the removal of Cu(II) and Ni(II) metal ions from aqueous solution. The effect of sorbent amount, agitation period and pH of solution that influence sorption capacity were investigated. From the observed results, it was evident that the adsorption of metal ions increases with the increase in contact time and adsorbent dosage. The optimum pH was found to be 5.0 for the removal of copper(II) and nickel(II) for both the extracted cellulose and cellulose-g-acrylic acid copolymer. The adsorption data were modeled using Langmuir and Freundlich isotherms. The experimental results of the Langmuir, Freundlich isotherms revealed that the adsorption of Cu(II) and nickel(II) ion onto cellulose extracted from the sisal fiber and cellulose-g-acrylic acid copolymer was found to fit well with Freundlich isotherm. The kinetics studies show that the adsorption follows the pseudo-second-order kinetics. From the above results, it was concluded that the cellulose-g-acrylic acid copolymer was found to be an efficient adsorbent. PMID:23994787

  16. 40 CFR 721.10526 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1-dodecanethiol, N-(hydroxymethyl)-2-methyl-2-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated (generic). 721.10526 Section 721.10526...

  17. 40 CFR 721.10526 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, telomers with C18-26-alkyl acrylate, 1-dodecanethiol, N-(hydroxymethyl)-2-methyl-2-propenamide, polyfluorooctyl methacrylate and vinylidene chloride, 2,2'- hydrochloride (1:2)-initiated (generic). 721.10526 Section 721.10526...

  18. A new coordination mode of (E)-3-(3-hydroxyl-phenyl)-acrylic acid in copper complex: Crystal structure and magnetic properties

    SciTech Connect

    Jin, Xin; Zhou, Pei; Zheng, Chunying; Li, Hui

    2015-05-15

    A copper complex ([Cu(py){sub 2}(L){sub 2}]·2CH{sub 3}OH){sub n} (HL=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) (1) with acrylic acid ligand was synthesized and structurally analyzed by IR, elemental analysis, TGA and the single-crystal X-ray diffraction methods. It is the first time to find that phenolic hydroxyl of L coordinates to Cu(II). Complex 1 exhibits 1D chain by a double-bridge of ligands, and the 3D supramolecular framework in complex 1 is constructed by π–π stacking interactions and van der Waals Contacts among the 1D chains. The magnetic properties of complex 1 have been studied. - Graphical abstract: A copper complex based on (E)-3-(3-hydroxyl-phenyl)-acrylic acid in a novel coordinated way was synthesized and a ferromagnetic exchange interactions between neighboring Cu(II) ions has be achieved. - Highlights: • A new copper complex with acrylic acid ligand was synthesized and analyzed. • We find the phenolic hydroxyl of MCA ligand coordinates to metal ion firstly. • A ferromagnetic exchange interactions between Cu(II) ions has been achieved.

  19. Investigation of PAA/PVDF-NZVI hybrids for metronidazole removal: synthesis, characterization, and reactivity characteristics.

    PubMed

    Yang, Jiacheng; Wang, Xiangyu; Zhu, Minping; Liu, Huiling; Ma, Jun

    2014-01-15

    For the first time, the removal process of metronidazole (MNZ) from aqueous solutions over nano zerovalent iron (NZVI) encapsulated within poly(acrylic acid) (PAA)/poly(vinylidene fluoride) (PVDF) membranes was reported. The resultant composite (PPN) demonstrated high reactivity, excellent stability and reusability over the reaction course. Such excellent performance might be attributed to the presence of the charged carboxyl groups in PVDF membrane support, which could enhance NZVI dispersion and improve its longevity. Results showed that a lower initial concentration and higher reaction temperature facilitated the removal of MNZ by PPN, and that the acidic and neutral conditions generally exhibited more favorable effect on MNZ removal than the alkaline ones. Kinetics of the MNZ removal by PPN was found to follow a two-parameter pseudo-first-order decay model well, and the activation energy of the MNZ degradation by PPN was determined to be 30.49kJ/mol. The presence of chloride ions slightly enhanced the reactivity of PPN with MNZ, whereas sulfate ions inhibited its reactivity. In addition, MNZ degradation pathways by PPN were proposed based on the identified intermediates. This study suggests that PPN composite possessing excellent performance may be a promising functional material to pretreat antibiotic wastewaters.

  20. Synthesis of perm-selective membranes by grafting acrylic acid into air-irradiated Teflon-FEP films

    NASA Astrophysics Data System (ADS)

    Bozzi, Annick; Chapiro, Adolphe

    Grafting acrylic acid into air-irradiated Teflon-FEP films was investigated. Pre-irradiation doses ranged from 0.5 to 10 kGy. Grafting occurred at 45 or 60°C. Homopolymerization inhibitors, ferrous ions or methylene blue, were added to the system. It was found that after completion of the reaction, within 40-100 min, membranes were obtained with very low electric resistivities. The influence of added inhibitors, pre-irradiation dose and grafting temperature was studied. From the results it is concluded that the initiating centers in air-irradiated Teflon-FEP are, on the one hand, peroxides of structure POOP', in which P is a polymeric radical and Pprime; a small fragment, and on the other trapped PO .2 radicals. The latter only react after losing their oxygen. In the presence of polymerization inhibitors, initiation involves a redox process which reduces the overall activation energy.

  1. Synthesis, characterization and electrical properties of Fe3O4/poly(vinyl alcohol-co-acrylic acid) nanocomposites

    NASA Astrophysics Data System (ADS)

    P, Jayakrishnan; Ramesan, M. T.

    2014-10-01

    This work focused on the synthesis of magnetite (Fe3O4)/poly(vinyl alcohol-co-acrylic acid) nanocomposite by in situ polymerization. The composite were characterized by FT-IR spectroscopy, XRD, SEM, TGA, AC and DC conductivity measurements. The spectroscopic studies revealed the molecular interaction between the polymer and nanocomposites. SEM, XRD indicated the uniform dispersion of nanoparticle inside the molecular chain of copolymer. TGA studies indicated the excellent thermal stability of copolymer nanocomposites. AC and DC conductivity of nanocomposites were higher than that of the copolymer and conductivity values were significantly increased with increase in concentration of metal oxide nanoparticles. These properties suggest that the polymer composite can be used as multifunctional material for nanoelectronics.

  2. Poly(acrylic acid)-directed synthesis of colloidally stable single domain magnetite nanoparticles via partial oxidation

    NASA Astrophysics Data System (ADS)

    Altan, Cem L.; Gurten, Berna; Sadza, Roel; Yenigul, Elcin; Sommerdijk, Nico A. J. M.; Bucak, Seyda

    2016-10-01

    Octahedral, single domain magnetite nanoparticles with average size of ~55 nm were synthesized through oxidative aging of a ferrous hydroxide (Fe(OH)2) precursor at high pH in water. The synthesis was also carried out in the presence of the hydrophilic polymer poly(acrylic acid). Presence of the polymer changed the particle morphology from octahedral to spherical while average size decreased to 40-50 nm. Although these particles have a tendency to precipitate due to their high magnetic moment, dispersions of these particles were obtained in the presence of this particular polymer which made the particles stable in water for several days making them suitable for various biotechnological applications such as cell separation owing to their low toxicity.

  3. Removal of reactive dyes from textile wastewater by immobilized chitosan upon grafted Jute fibers with acrylic acid by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Hassan, Mahmoud S.

    2015-10-01

    Jute fibers were grafted with acrylic acid by gamma irradiation technique. Chitosan was immobilized upon the grafted Jute fibers to be used as an adsorbent for waste reactive dye. The treated Jute fibers were characterized by using of Fourier-transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effect of Jute treatment on its thermal stability by using thermogravimetric analysis (TGA) and its mechanical properties were investigated. The adsorption isotherm and the different factors affecting the dye adsorption such as pH and contact time were also studied. It was found that the dye adsorption was enhanced in the low pH range and increased with increasing of the contact time, regardless of temperature change.

  4. Preparation and Properties of Ethylene Vinyl Acetate Copolymer/Silica Nanocomposites in Presence of EVA-g-Acrylic Acid.

    PubMed

    Tham, Do Quang; Tuan, Vu Manh; Thanh, Dinh Thi Mai; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Trang, Nguyen Thi Thu; Hang, To Thi Xuan; Huong, Ho Thu; Dung, Nguyen Thi Kim; Hoang, Thai

    2015-04-01

    Here we report a facile approach to enhance the dispersibility of ethylene vinyl acetate copolymer (EVA)/silica nanocomposites (for the EVA/silica nanocomposites and interaction between silica nanoparticles (nanosilica) and EVA by adding EVA-g-acrylic acid (EVAgAA) as a compatibilizer, which was formed by grafting acrylic acid onto EVA chains with the aid of dicumyl peroxide). The above nanocomposites with and without EVAgAA were prepared by melt mixing in a Haake intermixer with different contents of silica and EVAgAA. Their structure and morphology were characterized by Fourier transform infra-red (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), and the mechanical, rheological, dielectrical, and flammability properties of the nanocomposites were also investigated. The FT-IR spectra of the nanocomposites confirmed the formation of hydrogen bonds between the surface silanol groups of nanosilica and C=O groups of EVA and/or EVAgAA. The presence of EVAgAA remarkably increased the intensity of hydrogen bonding between nanosilica and EVA which not only enhanced the dispersion of nanosilica in EVA matrix but also increased the mechanical, viscosity and storage modulus of EVA/silica nanocomposites. In addition, the flammability of EVA/silica nanocomposites is also significantly reduced after the functionalization with EVAgAA. However, the mechanical properties of EVA/silica nanocomposites tended to level off when its content was above 1.5 wt.%. It has also been found that the dielectric constant value of the EVA/EVAgAA/silica nanocomposites is much lower than that of the EVA/silica nanocomposites, which is another evidence of the hydrogen bonding formation between EVAgAA and nanosilica. PMID:26353492

  5. Preparation and evaluation of MRI detectable poly (acrylic acid) microspheres loaded with superparamagnetic iron oxide nanoparticles for transcatheter arterial embolization.

    PubMed

    Wang, Huan; Qin, Xiao-Ya; Li, Zi-Yuan; Guo, Li-Ying; Zheng, Zhuo-Zhao; Liu, Li-Si; Fan, Tian-Yuan

    2016-09-25

    To monitor the spatial distribution of embolic particles inside the target tissues during and after embolization, blank poly (acrylic acid) microspheres (PMs) were initially prepared by inverse suspension polymerization method and then loaded with superparamagnetic iron oxide (SPIO) nanoparticles by in situ precipitation method to obtain magnetic resonance imaging (MRI) detectable SPIO-loaded poly (acrylic acid) microspheres (SPMs). The loading of SPIO nanoparticles in SPMs was confirmed by vibrating sample magnetometer, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and infrared spectrum, respectively. The results showed that SPMs exhibited excellent superparamagnetism and the SPIO embedded in SPMs were proved to be inverse spinel magnetite. The content of SPIO loaded in wet SPMs of subgroups of 100-300, 300-500, 500-700 and 700-900μm was measured to be 11.84±0.07, 10.20±0.05, 9.98±0.00 and 8.79±0.01mg/ml, corresponding to the weight percentage in freeze-dried SPMs to be 18.07±0.28%, 18.54±0.13%, 18.66±0.01% and 18.50±0.07%, respectively. The SPMs were spherical in shape, had smooth surface, and were within the size range of clinical demands for embolization. The compression tests indicated that SPMs were more rigid than PMs and commercially used Embospheres (P<0.01). The MRI detectability of SPMs was evaluated with the SPMs embedded in gel phantom in vitro and injected subcutaneously into the back of mice in vivo. Both the results demonstrated that the SPMs could provide distinct negative contrast enhancement and be sensitively detected by T2-weighted MR imaging. All the results show that SPMs are potential MRI detectable embolic microspheres for the future embolotherapy. PMID:27426106

  6. Insulin release from islets of Langerhans entrapped in a poly(N-isopropylacrylamide-co-acrylic acid) polymer gel.

    PubMed

    Vernon, B; Kim, S W; Bae, Y H

    1999-01-01

    A copolymer of N-isopropylacrylamide (98 mol% in feed) and acrylic acid, poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAAm-co-AAc)), was prepared by free radical polymerization for development of a thermally reversible polymer to entrap islets of Langerhans for a refillable biohybrid artificial pancreas. A 5 wt% solution of the polymer in Hanks' balanced salt solution forms a gel at 37 degrees C that exhibits no syneresis. Diffusion of fluorescein isothiocyanate (FITC) dextrans having molecular weights of 4400 and 70000 were used to evaluate mass transport in the gel at 37 degrees C. Insulin secretion from islets in the polymer gel was also investigated in both static and dynamic systems. The polymer gel exhibited excellent diffusion of FITC dextran 4400 and FITC dextran 70000 with diffusion ratios, D/D0 (ratio of diffusion in the gel to diffusion in water), of 0.20+/-0.04 and 0.35+/-0.17, respectively. Human islets entrapped in the polymer gel showed prolonged insulin secretion in response to basal (5.5 mM) glucose concentration compared to free human islets. Rat islets showed prolonged insulin secretion in response to high (16.5 mM) glucose concentrations compared to free rat islets. Rat islets in the polymer gel maintained insulin secretion in response to the higher glucose concentration for over 26 days. Rat islets entrapped by the polymer also released higher quantities of insulin more rapidly in response to changes in concentrations of glucose and other stimulants than rat islets entrapped in an alginate control. These results suggest that this material would provide adequate diffusion for rapid insulin release in an application as a synthetic extracellular matrix for a biohybrid artificial pancreas.

  7. Preparation and Properties of Ethylene Vinyl Acetate Copolymer/Silica Nanocomposites in Presence of EVA-g-Acrylic Acid.

    PubMed

    Tham, Do Quang; Tuan, Vu Manh; Thanh, Dinh Thi Mai; Chinh, Nguyen Thuy; Giang, Nguyen Vu; Trang, Nguyen Thi Thu; Hang, To Thi Xuan; Huong, Ho Thu; Dung, Nguyen Thi Kim; Hoang, Thai

    2015-04-01

    Here we report a facile approach to enhance the dispersibility of ethylene vinyl acetate copolymer (EVA)/silica nanocomposites (for the EVA/silica nanocomposites and interaction between silica nanoparticles (nanosilica) and EVA by adding EVA-g-acrylic acid (EVAgAA) as a compatibilizer, which was formed by grafting acrylic acid onto EVA chains with the aid of dicumyl peroxide). The above nanocomposites with and without EVAgAA were prepared by melt mixing in a Haake intermixer with different contents of silica and EVAgAA. Their structure and morphology were characterized by Fourier transform infra-red (FT-IR) spectroscopy, field emission scanning electron microscopy (FE-SEM), and the mechanical, rheological, dielectrical, and flammability properties of the nanocomposites were also investigated. The FT-IR spectra of the nanocomposites confirmed the formation of hydrogen bonds between the surface silanol groups of nanosilica and C=O groups of EVA and/or EVAgAA. The presence of EVAgAA remarkably increased the intensity of hydrogen bonding between nanosilica and EVA which not only enhanced the dispersion of nanosilica in EVA matrix but also increased the mechanical, viscosity and storage modulus of EVA/silica nanocomposites. In addition, the flammability of EVA/silica nanocomposites is also significantly reduced after the functionalization with EVAgAA. However, the mechanical properties of EVA/silica nanocomposites tended to level off when its content was above 1.5 wt.%. It has also been found that the dielectric constant value of the EVA/EVAgAA/silica nanocomposites is much lower than that of the EVA/silica nanocomposites, which is another evidence of the hydrogen bonding formation between EVAgAA and nanosilica.

  8. Increased resistance of Escherichia coli to acrylic acid and to copper ions after cold-shock.

    PubMed

    Whiting, G C; Rowbury, R J

    1995-04-01

    The effects of cold-shock on the resistance of plasmid-free and plasmid-carrying Escherichia coli to acrylate and copper ions have been tested. Such shock, produced by transfer from 37 to 5 degrees C, with 60 min incubation at the lower temperature, significantly enhanced the resistance of all the tested strains to both inhibitors. Such resistances may have arisen because the inhibitory agents are less able, due to porin changes, to penetrate into the organisms after cold-shock. It is more likely, however, that inhibitor penetration is unaffected but that cold-shocked organisms are better able to repair the damage caused (e.g. to membranes, DNA or cellular enzymes) by the inhibitors.

  9. Preparation of poly(acrylamide-co-acrylic acid)-grafted gum and its flocculation and biodegradation studies.

    PubMed

    Mittal, H; Mishra, Shivani B; Mishra, A K; Kaith, B S; Jindal, R; Kalia, S

    2013-10-15

    Biodegradation studies of Gum ghatti (Gg) and acrylamide-co-acrylic acid based flocculants [Gg-cl-poly(AAm-co-AA)] have been reported using the soil composting method. Gg-cl-poly(AAm-co-AA) was found to degrade 89.76% within 60 days. The progress of biodegradation at each stage was monitored through FT-IR and SEM. Polymer was synthesized under pressure using potassium persulphate-ascorbic acid as a redox initiator and N,N'-methylene-bis-acrylamide as a crosslinker. Synthesized polymer was found to show pH, temperature and ionic strength of the cations dependent swelling behavior. Gg-cl-poly(AAm-co-AA) was utilized for the selective absorption of saline from different petroleum fraction-saline emulsions. The flocculation efficiency of the polymer was studied as a function of polymer dose, temperature and pH of the solution. Gg-cl-poly(AAm-co-AA) showed maximum flocculation efficiency with 20 mol L(-1) polymer dose in acidic medium at 50 °C. PMID:23987360

  10. In vitro release studies of vitamin B 12 from poly N-vinyl pyrrolidone/starch hydrogels grafted with acrylic acid synthesized by gamma radiation

    NASA Astrophysics Data System (ADS)

    Eid, M.

    2008-12-01

    Co-polymeric hydrogels containing N-vinyl pyrrolidone and starch grafted with acrylic acid were synthesized by gamma radiation to be used as drug delivery system. Their gel contents, grafting swelling and thermal gravimetric analysis were evaluated. The gel content increases by increasing the irradiation dose up to 50 kGy, then decreases. The grafting percent increases by the increasing of acrylic acid. The thermal stability and the rate of the thermal decomposition changed according to the different compositions. The maximum rate of the thermal decomposition decreases by increasing the irradiation dose from 20 to 30 kGy and increases by increasing the irradiation dose from 30 to 70 kGy. The hydrogels loaded with vitamin B 12 demonstrated a decrease release in acidic medium than the neutral one.

  11. Fluorescent Ag nanoclusters prepared in aqueous poly(acrylic acid-co-maleic acid) solutions: a spectroscopic study of their excited state dynamics, size and local environment.

    PubMed

    Dandapat, Manika; Mandal, Debabrata

    2016-01-28

    Stable, fluorescent Ag nanoclusters were prepared in aqueous solutions of Na(+) salt of the carboxylate-rich polymer poly(acrylic acid-co-maleic acid) under brief spells of UV irradiation. The nanoclusters were nearly spherical, with diameters within 1.90 ± 0.50 nm, but displayed a prominent red edge excitation shift (REES) of fluorescence upon exciting within the visible absorption band, indicating heterogeneity of energy level distributions. Spectroscopic studies revealed that irrespective of whether the nanoclusters are excited in their UV or visible absorption bands, their fluorescence always ensues from the same manifold of emissive states, with a broad range of fluorescence lifetimes from ∼150 fs to 1 ns. PMID:26700465

  12. 21 CFR 173.5 - Acrylate-acrylamide resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... additive consists of one of the following: (1) Acrylamide-acrylic acid resin (hydrolyzed polyacrylamide) is... and acrylic acid, with the greater part of the polymer being composed of acrylamide units. (2)...

  13. Near-Infrared Light and pH-Responsive Polypyrrole@Polyacrylic acid/Fluorescent Mesoporous Silica Nanoparticles for Imaging and Chemo-Photothermal Cancer Therapy.

    PubMed

    Zhang, Manjie; Wang, Tingting; Zhang, Lingyu; Li, Lu; Wang, Chungang

    2015-11-01

    We have rationally designed a new theranostic agent by coating near-infrared (NIR) light-absorbing polypyrrole (PPY) with poly(acrylic acid) (PAA), in which PAA acts as a nanoreactor and template, followed by growing small fluorescent silica nanoparticles (fSiO2 NPs) inside the PAA networks, resulting in the formation of polypyrrole@polyacrylic acid/fluorescent mesoporous silica (PPY@PAA/fmSiO2 ) core-shell NPs. Meanwhile, DOX-loaded PPY@PAA/fmSiO2 NPs as pH and NIR dual-sensitive drug delivery vehicles were employed for fluorescence imaging and chemo-photothermal synergetic therapy in vitro and in vivo. The results demonstrate that the PPY@PAA/fmSiO2 NPs show high in vivo tumor uptake by the enhanced permeability and retention (EPR) effect after intravenous injection as revealed by in vivo fluorescence imaging, which is very helpful for visualizing the location of the tumor. Moreover, the obtained NPs inhibit tumor growth (95.6 % of tumors were eliminated) because of the combination of chemo-photothermal therapy, which offers a synergistically improved therapeutic outcome compared with the use of either therapy alone. Therefore, the present study provides new insights into developing NIR and pH-stimuli responsive PPY-based multifunctional platform for cancer theranostics.

  14. Radiation synthesis of hydrogels based on copolymers of vinyl ethers of monoethanolamine and ethyleneglycol and their interaction with poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Mun, G. A.; Nurkeeva, Z. S.; Khutoryanskiy, V. V.; Yermukhambetova, B. B.; Koblanov, S. M.; Arkhipova, I. A.

    2003-08-01

    Novel hydrogels of cationic nature were synthesized by gamma-radiation copolymerization of vinyl ethers of monoethanolamine and ethyleneglycol in the presence of cross-linking agent. The effect of absorbed dose on the gel fraction and equilibrium swelling degree of hydrogels in water is shown. It was demonstrated that the hydrogels are able to bind poly(acrylic acid) to form polyelectrolyte complexes with swelling properties typical for polyampholytes.

  15. Polyacrylic acid brushes grafted from P(St-AA)/Fe3O4 composite microspheres via ARGET-ATRP in aqueous solution for protein immobilization.

    PubMed

    Xie, Liqin; Lan, Fang; Li, Wenliao; Liu, Ziyao; Ma, Shaohua; Yang, Qi; Wu, Yao; Gu, Zhongwei

    2014-11-01

    Recently, the atom transfer radical polymerization (ATRP) of acrylic monomers in many reaction systems has been successfully accomplished. However, its application in aqueous solution is still a challenging task. In this work, polyacrylic acid (PAA) brushes with tunable length were directly grafted from P(St-AA)/Fe3O4 composite microspheres in aqueous solution via an improved method, activators regenerated by electron transfer atom transfer radical polymerization (ARGET-ATRP). This reaction was carried out in environment-friendly solvent. As well, this method overcame the sensitivity of the catalyst. Due to the strong coordination interaction of carboxyl groups, PAA brushes were employed for immobilizing gold nanoparticles, which were prepared via the in situ reduction of chloroauric acid. The PAA brushes modified magnetic composite microspheres decorating with gold nanoparticles were efficient for specific immobilization and separation of bovine serum albumin (BSA) from aqueous solution under the external magnetic field.

  16. Methyl acrylate

    Integrated Risk Information System (IRIS)

    Methyl acrylate ; CASRN 96 - 33 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  17. [The application of Harpagophytum procumbens extract in anti-inflammatory preparations applied on skin produced on acrylic acid polymers base].

    PubMed

    Piechota-Urbańska, Magdalena; Kołodziejska, Justyna; Berner-Strzelczyk, Aneta

    2009-01-01

    An attempt was made to use dry standardized extract from Harpagophytum procumbens of confirmed anti-inflammatory activity in formulations applied on skin. To obtain synergy in the area of analgesic and anti-inflammatory activity formulations were produced containing plant extract and nonsteroidal anti-inflammatory drug (ketoprofen). All the preparations were prepared on the base of acrylic acid polymers (Carbopol Ultrez 10, Carbopol 980). The formulations were subjected to complementary physicochemical investigations. Viscosity parameters (structural viscosity, yield stress, thixotrophy) were determined with cone-plate digital rheometer. Potentiometric method was used to measure pH of the produced hydrogels. The test for ketoprofen pharmaceutical availability through a semipermeable membrane to acceptor fluid was performed in vitro. The rate of the process of release was tested by determining the quantity of the therapeutic agent diffusing into acceptor fluid at defined time intervals by spectrophotometric method. The effect of Harpagophytum procumbens extract components on ketoprofen diffusion was estimated. Viscosity tests revealed that all the formulations are viscoelastic systems having yield stress. All model formulations were tested 24h after production and after 6-month storage. All the formulations demonstrate rheological stability and high pharmaceutical availability of ketoprofen. The suggested formulations can be an alternative for market preparations applied on skin of anti-inflammatory and analgesic activity. PMID:19873929

  18. Surface modification with poly(sulfobetaine methacrylate-co-acrylic acid) to reduce fibrinogen adsorption, platelet adhesion, and plasma coagulation.

    PubMed

    Kuo, Wei-Hsuan; Wang, Meng-Jiy; Chien, Hsiu-Wen; Wei, Ta-Chin; Lee, Chiapyng; Tsai, Wei-Bor

    2011-12-12

    Zwitterionic sulfobetaine methacrylate (SBMA) polymers were known to possess excellent antifouling properties due to high hydration capacity and neutral charge surface. In this study, copolymers of SBMA and acrylic acid (AA) with a variety of compositions were synthesized and were immobilized onto polymeric substrates with layer-by-layer polyelectrolyte films via electrostatic interaction. The amounts of platelet adhesion and fibrinogen adsorption were determined to evaluate hemocompatibility of poly(SBMA-co-AA)-modified substrates. Among various deposition conditions by modulating SBMA ratio in the copolymers and pH of the deposition solution, poly(SBMA(56)-co-AA(44)) deposited at pH 3.0 possessed the best hemocompatibility. This work demonstrated that poly(SBMA-co-AA) copolymers adsorbed on polyelectrolyte-base films via electrostatic interaction improve hemocompatibility effectively and are applicable for various substrates including TCPS, PU, and PDMS. Furthermore, poly(SBMA-co-AA)-coated substrate possesses great durability under rigorous conditions. The preliminary hemocompatibility tests regarding platelet adhesion, fibrinogen adsorption, and plasma coagulation suggest the potential of this technique for the application to blood-contacting biomedical devices. PMID:22077421

  19. Poly(N-isopropylacrylamide-co-acrylic acid) nanogels for tracing and delivering genes to human mesenchymal stem cells.

    PubMed

    Park, Ji Sun; Yang, Han Na; Woo, Dae Gyun; Jeon, Su Yeon; Park, Keun-Hong

    2013-11-01

    Drugs, proteins, and cells can be macro- and micro-encapsulated by unique materials that respond to specific stimuli. The phases and hydrophobic interactions of these materials are reversibly altered by environmental stimuli such as pH and temperature. These changes can lead to self-assembly of the materials, which enables controlled drug release and safe gene delivery into cells and tissues. The fate of stem cells delivered by such methods is of great interest. The formation of transgenic tissues requires genes to be delivered safely into stem cells. A cell tracing vehicle and a gene delivery carrier were simultaneously introduced into human mesenchymal stem cells (hMSCs). A thermo-sensitive hydrogel, poly(N-isopropylacrylamide-co-acrylic acid) (p(NiPAAm-co-AAc)), was created to generate self-assembled nanoparticles with nanogel characteristics. Hydrophobic interactions mediated the binding of the carboxyl group on the outside of p(NiPAAm-co-AAc) with the amine group of iron oxide. Nanogels carrying iron oxide and a fluorescent dye were complexed with specific genes. These nanogels could be internalized by hMSCs, and the transplantation of these cells into mice was monitored by in vivo imaging. Self-assembled p(NiPAAm-co-dAAc) nanogels complexed with green fluorescent protein were highly expressed in hMSCs and are a potential material for gene delivery. PMID:23937912

  20. Synthesis and colon-specific drug delivery of a poly(acrylic acid-co-acrylamide)/MBA nanosized hydrogel.

    PubMed

    Ray, Debajyoti; Mohapatra, Dillip K; Mohapatra, Ranjit K; Mohanta, Guru P; Sahoo, Prafulla K

    2008-01-01

    Intravenous administration of 5-fluorouracil (5-FU) for colon cancer therapy produces severe systemic side-effects due to its cytotoxic effect on normal cells. The main objective of the present study was to develop novel oral site-specific delivery of 5-FU to the colon with less drug being released in the stomach or small intestine using biodegradable hydrogel, hydrogel nanoparticles and comparing the targeting efficiency of 5-FU to colon from both. Poly(acrylic acid-co-acrylamide) (P(AA-co-Am)) normal hydrogel and hydrogel nanoparticles (HN) were synthesized by free radical polymerization using N,N-methylene-bis-acrylamide (MBA) as cross-linker, potassium persulfate as reaction initiator and 5-FU was loaded. HN were found to be degradable in physiological medium and showed comparatively higher swelling in rat caecal medium (RCM). 5-FU entrapment was increased by increasing Am (wt%) monomer feed. In vitro release of 5-FU from normal hydrogel and HN in pH progressive medium, it was found that a AA/Am ratio of 25:75 showed higher release in RCM. The Higuchi model yielded good adjustment of in vitro release kinetics. A higher amount of 5-FU reached the colon in HN (61 +/- 2.1%) than normal hydrogel (40 +/- 3.6%) by organ biodistribution studies in albino rats.

  1. Starch-g-Poly-(N, N-dimethyl acrylamide-co-acrylic acid): an efficient Cr (VI) ion binder.

    PubMed

    Kolya, Haradhan; Roy, Anirban; Tripathy, Tridib

    2015-01-01

    Synthesis of Starch-g-(Poly N, N-dimethylacrylamide-co-acrylic acid) was carried out by solution polymerization technique using potassium perdisulfate (K(2)S(2)O(8)) as the initiator. The graft copolymer was characterized by measuring molecular weight, using size exclusion chromatography (SEC), FTIR spectroscopy and X-ray diffraction (XRD) studies. The synthetic graft copolymer was used for removal of hexavalent chromium ion [Cr (VI)] from its aqueous solution. Various operating variables affecting the metal sorption such as, the amount of adsorbent, solution pH, contact time, temperature and the Cr (VI) solution concentration were extensively investigated. FTIR and UV-VIS spectroscopy, cyclic voltammetry (CV) were employed to study the metal complexation. The adsorption data could be well described by the pseudo-second-order and Langmuir isotherm model which indicate a chemisorption process. Calculation of the various thermodynamic parameters for the adsorption was also done. The negative value of free energy change (ΔG°) indicates the spontaneous nature of the adsorption. PMID:25224290

  2. Synthesis and colon-specific drug delivery of a poly(acrylic acid-co-acrylamide)/MBA nanosized hydrogel.

    PubMed

    Ray, Debajyoti; Mohapatra, Dillip K; Mohapatra, Ranjit K; Mohanta, Guru P; Sahoo, Prafulla K

    2008-01-01

    Intravenous administration of 5-fluorouracil (5-FU) for colon cancer therapy produces severe systemic side-effects due to its cytotoxic effect on normal cells. The main objective of the present study was to develop novel oral site-specific delivery of 5-FU to the colon with less drug being released in the stomach or small intestine using biodegradable hydrogel, hydrogel nanoparticles and comparing the targeting efficiency of 5-FU to colon from both. Poly(acrylic acid-co-acrylamide) (P(AA-co-Am)) normal hydrogel and hydrogel nanoparticles (HN) were synthesized by free radical polymerization using N,N-methylene-bis-acrylamide (MBA) as cross-linker, potassium persulfate as reaction initiator and 5-FU was loaded. HN were found to be degradable in physiological medium and showed comparatively higher swelling in rat caecal medium (RCM). 5-FU entrapment was increased by increasing Am (wt%) monomer feed. In vitro release of 5-FU from normal hydrogel and HN in pH progressive medium, it was found that a AA/Am ratio of 25:75 showed higher release in RCM. The Higuchi model yielded good adjustment of in vitro release kinetics. A higher amount of 5-FU reached the colon in HN (61 +/- 2.1%) than normal hydrogel (40 +/- 3.6%) by organ biodistribution studies in albino rats. PMID:18973725

  3. [Preparation of Pb2+ imprinted acrylic acid-co-styrene and analysis of its adsorption properties by FAAS].

    PubMed

    Shawket, Abliz; Abdiryim, Supahun; Wang, Ji-De; Ismayil, Nurulla

    2011-06-01

    With lead ion template, acrylic acid as functional monomer, potassium persulfate as initiator, strytrene as framework monomer, lead ion imprinted polymers (Pb(II)-IIPs) were prepared using free emulsion polymerization method. The structure and morphology of the polymers were analyzed by UV-spectra, FTIR and scanning electron microscopy. The adsorption/ desorption and selectivity for Pb2+ were investigated by flame atomic absorption spectrometry (FAAS) as the detection means. The results show that compared with non-imprinted polymers(NIPs), the Pb(II)-IIPs had higher specific adsorption properties and selective recognition ability for Pb(II). The relative selectivity coefficient of Pb(II)-IIPs for Pb(II) was 6.25, 6.18, 6.25 and 6.38 in the presence of Cd(II), Cu(II), Mn(II) and Zn(II) interferences, respectively. The absorption rate was the best at the pH of adsorbent solution of 6, Adsorption rate reached 96% during the 2.5 h static adsorption time. Using 3.0 mol x L(-1) HCI as the best desorption solvent to desorb the adsorbents, the desorbtion rate reached 98%. Under the best adsorption conditions, the adsorption capacity of Pb(II)-IIPs for Pb(II) was found to be 40. mg x g(-1). PMID:21847962

  4. Surface functionalization of an osteoconductive filler by plasma polymerization of poly(ε-caprolactone) and poly(acrylic acid) films

    NASA Astrophysics Data System (ADS)

    Petisco-Ferrero, S.; Sánchez-Ilárduya, M. B.; Díez, A.; Martín, L.; Meaurio Arrate, E.; Sarasua, J. R.

    2016-11-01

    One of the major limitations found in the use of nanocomposites based on synthetic hydroxyapatite and polymeric matrix for bone-tissue regeneration lies in the poor interfacial adhesion between the inorganic filler and the polymer matrix. The integrity of the nanocomposite is severely compromised since, on the one hand, high surface fillers tend to form aggregates and on the other, there is no chemical bonding between these two different categories of materials. Thus, customized surface functionalization stands as an effective route to improve the interfacial behaviour between particles and polymeric matrices. Amongst the current state of development of coating technologies, the high film-chemistry controllability offered by plasma polymerization technology enhances the synthesis of polymeric films from virtually any starting organic monomer. In this sense, the work presented here provides strong evidences of surface functionalization achieved by plasma polymerization starting respectively from ε-caprolactone and acrylic acid monomers. The chemistry of the deposited films has been descriptively analysed by XPS demonstrating outstanding retention of monomer functionalities and FTIR spectra of the deposited films revealed a high resemblance to those obtained by conventional synthesis. Results provided thereof are expected to significantly contribute to improve the interfacial behaviour in terms of matrix-reinforcement compatibilization, of crucial importance for bone-tissue engineering applications.

  5. Ultrasensitive electrochemical immunosensor based on horseradish peroxidase (HRP)-loaded silica-poly(acrylic acid) brushes for protein biomarker detection.

    PubMed

    Zhao, Yan; Zheng, Yiqun; Kong, Rongmei; Xia, Lian; Qu, Fengli

    2016-01-15

    We report an ultrasensitive electrochemical immunosensor designed for the detection of protein biomarkers using horseradish peroxidase (HRP)-loaded silica-poly(acrylic acid) brushes (SiO2-SPAABs) as labels. HRP could be efficiently and stably accommodated in the three-dimensional architecture of the SiO2-SPAABs and the SiO2-SPAABs-HRP exhibited high catalytic performance towards o-phenylenediamine (OPD) oxidation in the presence of H2O2, which resulted in significant differential pulse voltammetric (DPV) response change and color change. Using human IgG (HIgG) as a model analyte, a sandwich-type immunosensor was constructed. In particular, graphene oxide (GO) and SiO2-SPAABs-HRP were used to immobilize capture antibody (Ab1) and bind a layer of detection antibody (Ab2), respectively. The current biosensor exhibited a good linear response of HIgG from 100pg/mL to 100μg/mL with a detection limit of 50pg/mL (S/N=5). The sensitivity was 6.70-fold higher than the conventional enzyme-linked immunosorbent assays. The immunosensor results were validated through the detection of HIgG in serum samples.

  6. Enhancing antibiofouling performance of Polysulfone (PSf) membrane by photo-grafting of capsaicin derivative and acrylic acid

    NASA Astrophysics Data System (ADS)

    Wang, Jian; Sun, Haijing; Gao, Xueli; Gao, Congjie

    2014-10-01

    Biofouling is a critical issue in membrane water and wastewater treatment. Herein, antibiofouling PSf membrane was prepared by UV-assisted graft polymerization of acrylic acid (AA) and a capsaicin derivative, N-(5-methyl-3-tert-butyl-2-hydroxy benzyl) acrylamide (MBHBA), on PSf membrane. AA and MBHBA were used as hydrophilic monomer and antibacterial monomer separately. The membranes were characterized by FTIR-ATR, contact angle, SEM, AFM, cross-flow filtration unit, antifouling and antibacterial measurements. Verification of MBHBA and AA that photo-chemically grafted onto the PSf membrane surface is confirmed by carbonyl stretching vibration at ∼1655 cm-1 and ∼1730 cm-1, separately. The increasing AA concentration accelerates the graft-polymerization of MBHBA and resulted in a more hydrophilic surface. Consequently, antifouling property of the membranes was improved on a large level. The flux recovery rate can achieve 100% during the cyclic test, which may be attributed to the more hydrophilic and smooth surface, as well as the decreased membrane pore size. Most importantly, the presence of AA in graft co-polymer does not affect the antibacterial activity of MBHBA. That may be induced by the increasing chain length and flexibility of the grafted polymer chains.

  7. Preparation and swelling behavior of a novel self-assembled β-cyclodextrin/acrylic acid/sodium alginate hydrogel.

    PubMed

    Huang, Zhanhua; Liu, Shouxin; Zhang, Bin; Wu, Qinglin

    2014-11-26

    A novel biodegradable β-cyclodextrin/acrylic acid/sodium alginate (CSA) hydrogel with a three-dimensional network structure was self-assembled by inverse suspension copolymerization. The CSA resin was pH sensitive and had good water absorption properties in pH 6-8 buffer solutions. At a β-CD:AA:SA mass ratio of 1:9:3 the CSA water absorbency was found to be 1403 g/g and the CSA hydrogel strength was 4.968 N. In 0.005-0.1 mol/L chloride salt and sulfate salt solutions the CSA water absorbencies increased as follows: NaCl>KCl>MgCl2>CaCl2>FeCl3, and Na2SO4>K2SO4>FeSO4>Al2(SO4)3, respectively. The release of water from the CSA hydrogel occurred slowly over 120 h. The biodegradation efficiency of the resin reached 85.3% for Lentinula edodes. The super water absorbency, good salt resistance and excellent water retention properties of CSA make it suitable for application as an agricultural water retention agent in saline soils. PMID:25256504

  8. Capture of Tumor Cells on Anti-EpCAM-Functionalized Poly(acrylic acid)-Coated Surfaces.

    PubMed

    Andree, Kiki C; Barradas, Ana M C; Nguyen, Ai T; Mentink, Anouk; Stojanovic, Ivan; Baggerman, Jacob; van Dalum, Joost; van Rijn, Cees J M; Terstappen, Leon W M M

    2016-06-15

    The presence of tumor cells in blood is predictive of short survival in several cancers and their isolation and characterization can guide toward the use of more effective treatments. These circulating tumor cells (CTC) are, however, extremely rare and require a technology that is sufficiently sensitive and specific to identify CTC against a background of billions of blood cells. Immuno-capture of cells expressing the epithelial cell adhesion molecule (EpCAM) are frequently used to enrich CTC from blood. The choice of bio conjugation strategy and antibody clone is crucial for adequate cell capture but is poorly understood. In this study, we determined the binding affinity constants and epitope binding of the EpCAM antibodies VU1D-9, HO-3, EpAb3-5, and MJ-37 by surface plasmon resonance imaging (SPRi). Glass surfaces were coated using a poly(acrylic acid) based coating and functionalized with anti-EpCAM antibodies. Binding of cells from the breast carcinoma cell line (SKBR-3) to the functionalized surfaces were compared. Although EpAb3-5 displayed the highest binding affinity HO-3 captured the highest amount of cells. Hence we report differences in the performance of the different antibodies and more importantly that the choice of antibody to capture CTC should be based on multiple assays.

  9. Synthesis of silica coated zinc oxide–poly(ethylene-co-acrylic acid) matrix and its UV shielding evaluation

    SciTech Connect

    Ramasamy, Mohankandhasamy; Kim, Yu Jun; Gao, Haiyan; Yi, Dong Kee; An, Jeong Ho

    2014-03-01

    Graphical abstract: - Highlights: • Well layer thickness controlled silica shell was made on ZnO nanoparticles. • PEAA, an interfacial agent is used to make nanocomposite–polymer matrix by twin-screw extruder. • Si-ZnO/PEAA matrix is highly stable and UV protective as compared to ZnO/PEAA matrix. • Nanoparticle embedded polymer matrix is suggested to make UV shielding fabrics with Nylon4. - Abstract: Silica coated zinc oxide nanoparticles (Si-ZnO NPs) (7 nm thick) were synthesized successfully and melt blended with poly(ethylene-co-acrylic acid) (PEAA resin) to improving ultraviolet (UV) shielding of zinc oxide nanoparticles (ZnO NPs). The photostability of both the ZnO NPs and Si-ZnO NPs were analyzed by the difference in photoluminescence (PL) and by methylene blue (MB) degradation. Photo-degradation studies confirmed that Si-ZnO NPs are highly photostable compared to ZnO NPs. The melt blended matrices were characterized by field emission scanning electron microscopy interfaced with energy dispersive X-ray spectroscopy (FE-SEM-EDX). The UV shielding property was analyzed from the transmittance spectra of UV–visible (UV–vis) spectroscopy. The results confirmed fine dispersion of thick Si-ZnO NPs in the entire resin matrix. Moreover, the Si-ZnO/PEAA showed about 97% UV shielding properties than the ZnO/PEAA.

  10. Binary immobilization of tyrosinase by using alginate gel beads and poly(acrylamide-co-acrylic acid) hydrogels.

    PubMed

    Yahşi, Ayşe; Sahin, Ferat; Demirel, Gökhan; Tümtürk, Hayrettin

    2005-09-15

    The use of the immobilized and the stable enzymes has immense potential in the enzymatic analysis of clinical, industrial and environmental samples. However, their widespread uses are limited due to the high cost of their production. In this study, binary immobilization of tyrosinase by using Ca-alginate and poly(acrylamide-co-acrylic acid) [P(AAm-co-AA)] was investigated. Maximum reaction rate (Vmax) and Michaelis-Menten constant (Km) were determined for the free and binary immobilized enzymes. The effects of pH, temperature, storage stability, reuse number and thermal stability on the free and immobilized tyrosinase were also examined. For the free and binary immobilized enzymes on Ca-alginate and P(AAm-co-AA), optimum pH was found to be 7 and 5, respectively. Optimum temperature of the free and immobilized enzymes was observed to be 30 and 35 degrees C, respectively. Reuse number, storage and thermal stability of the free tyrosinase were increased by a result of binary immobilization.

  11. Characterization and Antimicrobial Property of Poly(Acrylic Acid) Nanogel Containing Silver Particle Prepared by Electron Beam

    PubMed Central

    Choi, Jong-Bae; Park, Jong-Seok; Khil, Myung-Seob; Gwon, Hui-Jeong; Lim, Youn-Mook; Jeong, Sung-In; Shin, Young-Min; Nho, Young-Chang

    2013-01-01

    In this study, we developed a one step process to synthesize nanogel containing silver nanoparticles involving electron beam irradiation. Water-soluble silver nitrate powder is dissolved in the distilled water and then poly(acrylic acid) (PAAc) and hexane are put into this silver nitrate solution. These samples are irradiated by an electron beam to make the PAAc nanogels containing silver nanoparticles (Ag/PAAc nanogels). The nanoparticles were characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). In addition, the particle size and zeta-potential were confirmed by a particle size analyzer (PSA). The antibacterial properties of the nanogels were evaluated by paper diffusion test. The Ag/PAAc nanogels had an antibacterial effect against Escherichia coli and Staphylococcus aureus. The nanogels also demonstrated a good healing effect against diabetic ulcer. The size of the Ag/PAAc nanogels decreased with increasing irradiation doses, and the absolute value of the zeta potential increased with increasing irradiation doses. Also, the Ag/PAAc nanogels exhibited good antibacterial activity against both Gram-negative and Gram-positive bacteria. In in vivo wound healing, the Ag/PAAc nanogels have a good healing effect. PMID:23708101

  12. Assessment of multicomponent hydrogel scaffolds of poly(acrylic acid-2-hydroxy ethyl methacrylate)/gelatin for tissue engineering applications.

    PubMed

    Jaiswal, Maneesh; Koul, Veena

    2013-03-01

    The article describes the design of the multicomponent hydrogel system of poly(acrylic acid-HEMA)/gelatin for tissue engineering application. Derivative of polycaprolactone-diol (polycaprolactone diacrylate (PCL-DAr)) was used to cross-link acrylate monomers whereas gelatin was kept free for cell proliferation. Epigallocatechin gallate (EGCG), an anti-oxidant phytochemical, was loaded by diffusion method. Its in vitro release study in PBS (pH 6.5) at 37 ± 0.2°C (75 rpm) revealed a sustained release profile upto 20 days. Fitting of drug release data in Korsmeyer-Peppas model equation revealed probable release mechanism through the value of release coefficient (n), which was found to depend on formulations composition. Drug-polymer interaction, thermal behavior, and surface morphology were investigated by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, thermogravimetric analysis (TGA), and scanning electron microscopic (SEM). Swelling behavior of hydrogel in PBS (pH 6.5 and 7.4, 0.2 M) and in distilled water was found to increase with increasing AAc/HEMA ratio. Compression modulus decreased from 203 ± 3.7 KPa to 11.6 ± 1.1KPa, at 30% strain, whereas displacement values significantly increased from 3.2 ± 0.2 to 4.7 ± 0.6 mm at 20 N force (p < 0.05), with increasing AAc/HEMA ratio. Percentage cell viability was analyzed using indirect 3-[4, 5-dimethylthiazolyl-2]-2,5-diphenyltetrazo-liumbromide (MTT) assay with fibroblast L929 cells; showed ≥92.3% cell viability after 24 h incubation. Cell proliferation on the scaffold surface was found to increase with incorporation of HEMA in P(AAc)/G cross-linked hydrogel matrix upto a certain extent. These biocompatible, elastic, and swellable hydrogels can serve as a matrix for drug delivery and tissue engineering applications.

  13. Synthesis of Gold Nanoflowers Encapsulated with Poly(N-isopropylacrylamide-co-acrylic acid) Hydrogels.

    PubMed

    Bae, Saet-Byeol; Lee, Sang-Wha

    2015-10-01

    In this work, hydrogel-coated gold nanoflowers (AuNFs@hydrogel) were facilely prepared. First, gold nanoflowers (AuNFs) were synthesized by reducing gold acid with ascorbic acid in the presence of chitosan biopolymers, and the chitosan-mediated AuNFs were subsequently conjugated with oleic acid with carboxylate groups. Finally, the olefin-conjugated AuNFs were encapsulated with P(NIPAM-co-AAC) hydrogels via a radical polymerization reaction with co-monomer ratio of [NIPAM:AAc = 91:9 wt%]. The encapsulated hydrogels had a lower critical solution temperature (LCST) slightly above the physiological temperature and demonstrated a thermo-sensitive variation of particle size. The hydrogel-coated AuNFs can be utilized as a promising thermo-responsive drug delivery system with a unique optical property. As-prepared samples were characterized by DLS, SEM, TEM, UV-vis and Zeta potential meter. PMID:26726447

  14. Poly(acrylic acid)-block-poly(vinyl alcohol) anchored maghemite nanoparticles designed for multi-stimuli triggered drug release

    NASA Astrophysics Data System (ADS)

    Liu, Ji; Detrembleur, Christophe; Debuigne, Antoine; de Pauw-Gillet, Marie-Claire; Mornet, Stéphane; Vander Elst, Luce; Laurent, Sophie; Labrugère, Christine; Duguet, Etienne; Jérôme, Christine

    2013-11-01

    Original core/corona nanoparticles composed of a maghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug delivery system (DDS) application. This kind of DDS aims to combine the advantage of stimuli-responsive polymer coating, in order to regulate the drug release behaviours under different conditions and furthermore, improve the biocompatibility and in vivo circulation half-time of the maghemite nanoparticles. Drug loading capacity was evaluated with methylene blue (MB), a cationic model drug. The triggered release of MB was studied under various stimuli such as pH, ionic strength and temperature. Local heating generated under alternating magnetic field (AMF) application was studied, and remotely AMF-triggered release was also confirmed, while a mild heating-up of the release medium was observed. Furthermore, their potential application as magnetic resonance imaging (MRI) contrast agents was explored via relaxivity measurements and acquisition of T2-weighted images. Preliminary studies on the cytotoxicity against mouse fibroblast-like L929 cell line and also their cellular uptake within human melanoma MEL-5 cell line were carried out. In conclusion, this kind of stimuli-responsive nanoparticles appears to be promising carriers for delivering drugs to some tumour sites or into cellular compartments with an acidic environment.Original core/corona nanoparticles composed of a maghemite core and a stimuli-responsive polymer coating made of poly(acrylic acid)-block-poly(vinyl alcohol) macromolecules were fabricated for drug delivery system (DDS) application. This kind of DDS aims to combine the advantage of stimuli-responsive polymer coating, in order to regulate the drug release behaviours under different conditions and furthermore, improve the biocompatibility and in vivo circulation half-time of the maghemite nanoparticles. Drug loading capacity was evaluated with methylene

  15. Synthesis of TiO{sub 2} nanoparticles by self-assembling reverse micelle cores of PS-b-PAA for functional textile applications

    SciTech Connect

    Akpolat, Leyla Budama; Çakır, Burçin Acar; Topel, Önder Hoda, Numan

    2015-04-15

    Highlights: • TiO{sub 2} nanoparticles were synthesized within poly(styrene)-b-poly(acrylic acid) micelles. • The copolymer solution including nano TiO{sub 2} was coated onto textile fabrics. • UV-protective factor of nano TiO{sub 2} coated fabrics was estimated as 50+. • Nano TiO{sub 2} coated fabrics was found to exhibit a high photocatalytic activity. - Abstract: Titanium dioxide (i.e., titanium(IV) oxide, TiO{sub 2}) nanoparticles have been fabricated using a copolymer templating technique in micellar solution of poly(styrene)-block-poly(acrylic acid), PS(10912)-b-PAA(4842) synthesized by atom transfer radical polymerization (ATRP). The size and morphology of the synthesized TiO{sub 2} nanoparticles have been characterized via TEM and XRD measurements. The average size of TiO{sub 2} nanoparticles was determined as 13 ± 3 and 13 ± 4 nm for titanium:copolymer ratios of 20:1 and 33:1, respectively. The copolymer solution including nano TiO{sub 2} particles has been coated onto textile fabrics to enhance their UV-blocking and self-cleaning properties. It has been determined that nano TiO{sub 2} coated textile fabrics have very good UV-blocking properties with 50+ of the ultraviolet protecting factor (UPF) and high photocatalytic efficiency with 69.2% of the photodegradation of methylene blue.

  16. Extending framework based on the linear coordination polymers: Alternative chains containing lanthanum ion and acrylic acid ligand

    NASA Astrophysics Data System (ADS)

    Li, Hui; Guo, Ming; Tian, Hong; He, Fei-Yue; Lee, Gene-Hsiang; Peng, Shie-Ming

    2006-11-01

    One-dimensional alternative chains of two lanthanum complexes: [La( L1) 3(CH 3OH)(H 2O) 2]·5H 2O ( L1=anion of α-cyano-4-hydroxycinnamic acid ) 1 and [La( L2) 3(H 2O) 2]·3H 2O ( L2=anion of trans-3-(4-methyl-benzoyl)-acrylic acid) 2 were synthesized and structurally characterized by single-crystal X-ray diffraction, element analysis, IR and thermogravimetric analysis. The crystal structure data are as follows for 1: C 31H 36LaN 3O 17, triclinic, P-1, a=9.8279(4) Å, b=11.8278(5) Å, c=17.8730(7) Å, α=72.7960(10)°, β=83.3820(10)°, γ=67.1650(10)º, Z=2, R1=0.0377, wR2=0.0746; for 2: C 33H 37LaO 14, triclinic, P-1, a=8.7174(5) Å, b=9.9377(5) Å, c=21.153(2) Å, α=81.145(2)°, β=87.591(2)°, γ=67.345(5)°, Z=2, R1=0.0869, wR2=0.220. 1 is a rare example of the alternative chain constructed by syn-syn and anti-syn coordination mode of carboxylato ligand arranged along the chain alternatively. La(III) ions in 2 are linked by two η3-O bridges and four bridges (two η2-O and two η3-O) alternatively. Both of the linear coordination polymers grow into two- and three-dimensional networks by packing through extending hydrogen-bond network directed by ligands.

  17. A method for preparing sodium acrylate-d3, a useful and stable precursor for deuterated acrylic monomers

    SciTech Connect

    Yang, Jun; Hong, Kunlun; Bonnesen, Peter V

    2011-01-01

    A convenient and economical method for converting propiolic acid to sodium acrylate-d3 is described. Successive D/H exchange of the alkyne proton of sodium propiolate (prepared from propiolic acid) using D2O affords sodium propiolate-d having up to 99 atom% D. Sodium propiolate-d can be partially reduced to sodium acrylate-d3 with 90% conversion and 89% yield, using D2 and the Lindlar catalyst with control of reaction parameters to maximize conversion while minimizing over reduction.

  18. FT-IR and FT-Raman studies of cross-linking processes with Ca²⁺ ions, glutaraldehyde and microwave radiation for polymer composition of poly(acrylic acid)/sodium salt of carboxymethyl starch - In moulding sands, Part II.

    PubMed

    Grabowska, Beata; Sitarz, Maciej; Olejnik, Ewa; Kaczmarska, Karolina; Tyliszczak, Bozena

    2015-12-01

    The hardening process of moulding sands on quartz matrices bound by polymer binders containing carboxyl and hydroxyl groups can be carried out by using physical (microwave radiation, thermal holding) and chemical (Ca(2+) cations, glutaraldehyde) cross-linking agents. The highest hardening level obtain moulding sand samples containing binders in a form of the aqueous composition of poly(acrylic acid)/sodium salt of carboxymethyl starch (PAA/CMS-Na) within the microwave radiation field, for which the bending strength is of 1.6 MPa value even after 24h from ending the agent activity. The authors focused, in this study, on finding the reason of this effect. It was shown, by means of the FT-IR and FT-Raman spectroscopic methods, that the chemical adsorption process activated by microwaves plays an essential role. The applied microwaves activate the polar groups present in the polymer composition structure as well as the quartz crystals surfaces (silane groups). Then the chemical adsorption occurs in the binder-matrix system within the microwave radiation field and intermolecular lattices are formed with a participation of hydrogen bridges (SiOH⋯OC, SiOH⋯OH) and COSi type bonds. PMID:26125981

  19. Magnetic pH-responsive poly(methacrylic acid-co-acrylic acid)-co-polyvinylpyrrolidone magnetic nano-carrier for controlled delivery of fluvastatin.

    PubMed

    Amoli-Diva, Mitra; Pourghazi, Kamyar; Mashhadizadeh, Mohammad Hossein

    2015-02-01

    A novel pH-responsive polymer, poly(methacrylic acid-co-acrylic acid)-co-polyvinyl-pyrrolidone (polymeric nano-carrier) was synthesized and used for encapsulation of 3-aminopropyl triethoxysilane modified Fe3O4 nanoparticles to prepare a new magnetic nano-carrier. The loading and release characteristics of both polymeric and magnetic nano-carriers were investigated using fluvastatin as the model drug. The loading behavior of the carriers was studied by varying concentration of fluvastatin in aqueous medium at 25°C and their release was followed spectrophotometrically (at 304 nm) at 37°C in three different solutions (buffered at pH1.2, 5.5 and 7.2) to simulate gastric and intestine medium. The effect of different parameters on the release of fluvastatin such as the amount of methacrylic acid monomer, cross-linker amount, initiator amount, and magnetic nanoparticles content was also studied. Considering the release kinetics and mechanism of the magnetic nanocarrier besides swelling behavior study of the polymeric nano-carrier reveal Fickian pattern and diffusion controlled mechanism for delivery of fluvastatin.

  20. Effect of chemical composition on corneal cellular response to photopolymerized materials comprising 2-hydroxyethyl methacrylate and acrylic acid.

    PubMed

    Lai, Jui-Yang

    2013-10-01

    Characterization of corneal cellular response to hydrogel materials is an important issue in ophthalmic applications. In this study, we aimed to investigate the relationship between the feed composition of 2-hydroxyethyl methacrylate (HEMA)/acrylic acid (AAc) and material compatibility towards corneal stromal and endothelial cells. The monomer solutions of HEMA and AAc were mixed at varying volume ratios of 92:0, 87:5, 82:10, 77:15, and 72:20, and were subjected to UV irradiation. Results of electrokinetic measurements showed that an increase in absolute zeta potential of photopolymerized membranes is observed with increasing the volume ratios of AAc/HEMA. Following 4 days of incubation with various hydrogels, the primary rabbit corneal stromal and endothelial cell cultures were examined for viability, proliferation, and pro-inflammatory gene expression. The samples prepared from the solution mixture containing 0-10 vol.% AAc displayed good cytocompatibility. However, with increasing volume ratio of AAc and HEMA from 15:77 to 20:72, the decreased viability, inhibited proliferation, and stimulated inflammation were noted in both cell types, probably due to the stronger charge-charge interactions. On the other hand, the ionic pump function of corneal endothelial cells exposed to photopolymerized membranes was examined by analyzing the Na(+),K(+)-ATPase alpha 1 subunit (ATP1A1) expression level. The presence of material samples having higher anionic charge density (i.e., zeta potential of -38 to -56 mV) may lead to abnormal transmembrane transport. It is concluded that the chemical composition of HEMA/AAc has an important influence on the corneal stromal and endothelial cell responses to polymeric biomaterials. PMID:23910267

  1. Effect of chemical composition on corneal tissue response to photopolymerized materials comprising 2-hydroxyethyl methacrylate and acrylic acid.

    PubMed

    Lai, Jui-Yang

    2014-01-01

    The purpose of this work was to investigate the relationship between the feed composition of 2-hydroxyethyl methacrylate (HEMA)/acrylic acid (AAc) and hydrogel material compatibility towards ocular anterior segment tissues, particularly the corneal endothelium. The monomer solutions of HEMA and AAc were mixed at varying volume ratios of 92:0, 87:5, 82:10, 77:15, and 72:20, and were subjected to UV irradiation. Then, the 7-mm-diameter membrane implants made from photopolymerized materials were placed into the ocular anterior chamber for 4days and assessed by biomicroscopic examinations, corneal thickness measurements, and quantitative real-time reverse transcription polymerase chain reaction analyses. The poly(HEMA-co-AAc) implants prepared from the solution mixture containing 0-10vol.% AAc displayed good biocompatibility. However, with increasing volume ratio of AAc and HEMA from 15:77 to 20:72, the enhanced inflammatory response, decreased endothelial cell density, and increased ocular score and corneal thickness were observed, probably due to the influence of surface charge of copolymer membranes. On the other hand, the ionic pump function of corneal endothelium exposed to photopolymerized membranes was examined by analyzing the Na(+),K(+)-ATPase alpha 1 subunit (ATP1A1) expression level. The presence of the implants having higher amount of AAc incorporated in the copolymers (i.e., 15.1 to 24.7μmol) and zeta potential (i.e., -38.6 to -56.5mV) may lead to abnormal transmembrane transport. It is concluded that the chemical composition of HEMA/AAc has an important influence on the corneal tissue responses to polymeric biomaterials. PMID:24268266

  2. Self-assembled poly(ethylene glycol)-co-acrylic acid microgels to inhibit bacterial colonization of synthetic surfaces.

    PubMed

    Wang, Qichen; Uzunoglu, Emel; Wu, Yong; Libera, Matthew

    2012-05-01

    We explored the use of self-assembled microgels to inhibit the bacterial colonization of synthetic surfaces both by modulating surface cell adhesiveness at length scales comparable to bacterial dimensions (∼1 μm) and by locally storing/releasing an antimicrobial. Poly(ethylene glycol) [PEG] and poly(ethylene glycol)-co-acrylic acid [PEG-AA] microgels were synthesized by suspension photopolymerization. Consistent with macroscopic gels, a pH dependence of both zeta potential and hydrodynamic diameter was observed in AA-containing microgels but not in pure PEG microgels. The microgels were electrostatically deposited onto poly(l-lysine) (PLL) primed silicon to form submonolayer surface coatings. The microgel surface density could be controlled via the deposition time and the microgel concentration in the parent suspension. In addition to their intrinsic antifouling properties, after deposition, the microgels could be loaded with a cationic antimicrobial peptide (L5) because of favorable electrostatic interactions. Loading was significantly higher in PEG-AA microgels than in pure PEG microgels. The modification of PLL-primed Si by unloaded PEG-AA microgels reduced the short-term (6 h) S. epidermidis surface colonization by a factor of 2, and the degree of inhibition increased when the average spacing between microgels was reduced. Postdeposition L5 peptide loading into microgels further reduced bacterial colonization to the extent that, after 10 h of S. epidermidis culture in tryptic soy broth, the colonization of L5-loaded PEG-AA microgel-modified Si was comparable to the very small level of colonization observed on macroscopic PEG gel controls. The fact that these microgels can be deposited by a nonline-of-sight self-assembly process and hinder bacterial colonization opens the possibility of modifying the surfaces of topographically complex biomedical devices and reduces the rate of biomaterial-associated infection.

  3. Hydrogen-bonding-driven self-assembly of PEGylated organosilica nanoparticles with poly(acrylic acid) in aqueous solutions and in layer-by-layer deposition at solid surfaces.

    PubMed

    Irmukhametova, Galiya S; Fraser, Brian J; Keddie, Joseph L; Mun, Grigoriy A; Khutoryanskiy, Vitaliy V

    2012-01-10

    PEGylated organosilica nanoparticles have been synthesized through self-condensation of (3-mercaptopropyl)trimethoxysilane in dimethyl sulfoxide into thiolated nanoparticles with their subsequent reaction with methoxypoly(ethylene glycol) maleimide. The PEGylated nanoparticles showed excellent colloidal stability over a wide range of pH in contrast to the parent thiolated nanoparticles, which have a tendency to aggregate irreversibly under acidic conditions (pH < 3.0). Due to the presence of a poly(ethylene glycol)-based corona, the PEGylated nanoparticles are capable of forming hydrogen-bonded interpolymer complexes with poly(acrylic acid) in aqueous solutions under acidic conditions, resulting in larger aggregates. The use of hydrogen-bonding interactions allows more efficient attachment of the nanoparticles to surfaces. The alternating deposition of PEGylated nanoparticles and poly(acrylic acid) on silicon wafer surfaces in a layer-by-layer fashion leads to multilayered coatings. The self-assembly of PEGylated nanoparticles with poly(acrylic acid) in aqueous solutions and at solid surfaces was compared to the behavior of linear poly(ethylene glycol). The nanoparticle system creates thicker layers than the poly(ethylene glycol), and a thicker layer is obtained on a poly(acrylic acid) surface than on a silica surface, because of the effects of hydrogen bonding. Some implications of these hydrogen-bonding-driven interactions between PEGylated nanoparticles and poly(acrylic acid) for pharmaceutical formulations are discussed.

  4. Molecular Dynamics Simulations of Adsorption of Poly(acrylic acid) and Poly(methacrylic acid) on Dodecyltrimethylammonium Chloride Micelle in Water: Effect of Charge Density.

    PubMed

    Sulatha, Muralidharan S; Natarajan, Upendra

    2015-09-24

    We have investigated the interaction of dodecyltrimethylammonium chloride (DoTA) micelle with weak polyelectrolytes, poly(acrylic acid) and poly(methacrylic acid). Anionic as well as un-ionized forms of the polyelectrolytes were studied. Polyelectrolyte-surfactant complexes were formed within 5-11 ns of the simulation time and were found to be stable. Association is driven purely by electrostatic interactions for anionic chains whereas dispersion interactions also play a dominant role in the case of un-ionized chains. Surfactant headgroup nitrogen atoms are in close contact with the carboxylic oxygens of the polyelectrolyte chain at a distance of 0.35 nm. In the complexes, the polyelectrolyte chains are adsorbed on to the hydrophilic micellar surface and do not penetrate into the hydrophobic core of the micelle. Polyacrylate chain shows higher affinity for complex formation with DoTA as compared to polymethacrylate chain. Anionic polyelectrolyte chains show higher interaction strength as compared to corresponding un-ionized chains. Anionic chains act as polymeric counterion in the complexes, resulting in the displacement of counterions (Na(+) and Cl(-)) into the bulk solution. Anionic chains show distinct shrinkage upon adsorption onto the micelle. Detailed information about the microscopic structure and binding characteristics of these complexes is in agreement with available experimental literature. PMID:26355463

  5. Molecular Dynamics Simulations of Adsorption of Poly(acrylic acid) and Poly(methacrylic acid) on Dodecyltrimethylammonium Chloride Micelle in Water: Effect of Charge Density.

    PubMed

    Sulatha, Muralidharan S; Natarajan, Upendra

    2015-09-24

    We have investigated the interaction of dodecyltrimethylammonium chloride (DoTA) micelle with weak polyelectrolytes, poly(acrylic acid) and poly(methacrylic acid). Anionic as well as un-ionized forms of the polyelectrolytes were studied. Polyelectrolyte-surfactant complexes were formed within 5-11 ns of the simulation time and were found to be stable. Association is driven purely by electrostatic interactions for anionic chains whereas dispersion interactions also play a dominant role in the case of un-ionized chains. Surfactant headgroup nitrogen atoms are in close contact with the carboxylic oxygens of the polyelectrolyte chain at a distance of 0.35 nm. In the complexes, the polyelectrolyte chains are adsorbed on to the hydrophilic micellar surface and do not penetrate into the hydrophobic core of the micelle. Polyacrylate chain shows higher affinity for complex formation with DoTA as compared to polymethacrylate chain. Anionic polyelectrolyte chains show higher interaction strength as compared to corresponding un-ionized chains. Anionic chains act as polymeric counterion in the complexes, resulting in the displacement of counterions (Na(+) and Cl(-)) into the bulk solution. Anionic chains show distinct shrinkage upon adsorption onto the micelle. Detailed information about the microscopic structure and binding characteristics of these complexes is in agreement with available experimental literature.

  6. Preparation of Poly Acrylic Acid-Poly Acrylamide Composite Nanogels by Radiation Technique

    PubMed Central

    Ghorbaniazar, Parisa; Sepehrianazar, Amir; Eskandani, Morteza; Nabi-Meibodi, Mohsen; Kouhsoltani, Maryam; Hamishehkar, Hamed

    2015-01-01

    Purpose: Nanogel, a nanoparticle prepared from a cross-linked hydrophilic polymer network, has many biomedical applications. A radiation technique has recently been introduced as one of the appropriate methods for the preparation of polymeric nanogels due to its additive-free initiation and easy control procedure. Methods: We have investigated the formation of nano-sized polymeric gels, based on the radiation-induced inter- and intra-molecular cross-linking of the inter-polymer complex (IPC) of polyacrylamide (PAAm) and polyacrylic acide (PAAc). Results: The results indicated that the prepared polymeric complex composed of PAAm and PAAc was converted into nanogel by irradiation under different doses (1, 3, 5 and 7 kGy). This was due to inter- and intra-molecular cross-linking at the range of 446-930 nm as characterized by the photon correlation spectroscopy method. Increasing the irradiation dose reduced the size of nanoparticles to 3 kGy; however, the higher doses increased the size and size distribution. Scanning electron microscopy images indicated the nanogel formation in the reported size by particle size and showed the microcapsule structure of the prepared nanogels. Biocompatibility of nanogels were assessed and proved by MTT assay. Conclusion: It was concluded that low dose irradiation can be successfully applied for nanometre-ranged hydrogel. PMID:26236667

  7. Purification and preliminary characterization of (E)-3-(2,4-dioxo-6-methyl-5-pyrimidinyl)acrylic acid synthase, an enzyme involved in biosynthesis of the antitumor agent sparsomycin.

    PubMed

    Parry, R J; Hoyt, J C

    1997-02-01

    Sparsomycin is an antitumor antibiotic produced by Streptomyces sparsogenes. Biosynthetic experiments have previously demonstrated that one component of sparsomycin is derived from L-tryptophan via the intermediacy of (E)-3-(4-oxo-6-methyl-5-pyrimidinyl)acrylic acid and (E)-3-(2,4-dioxo-6-methyl-5-pyrimidinyl)acrylic acid. An enzyme which catalyzes the conversion of (E)-3-(4-oxo-6-methyl-5-pyrimidinyl)acrylic acid to (E)-3-(2,4-dioxo-6-methyl-5-pyrimidinyl)acrylic acid has been purified 740-fold to homogeneity from S. sparsogenes. The molecular mass of the native and denatured enzyme was 87 kDa, indicating that the native enzyme is monomeric. The enzyme required NAD+ for activity but lacked rigid substrate specificity, since analogs of both NAD+ and 3-(4-oxo-6-methyl-5-pyrimidinyl)acrylic acid could serve as substrates. The enzyme was very weakly inhibited by mycophenolic acid. Monovalent cations were required for activity, with potassium ions being the most effective. The enzyme exhibited sensitivity toward diethylpyrocarbonate and some thiol-directed reagents, and it was irreversibly inhibited by 6-chloropurine. The properties of the enzyme suggest it is mechanistically related to inosine-5'-monophosphate dehydrogenase. PMID:9023226

  8. Polyacrylic acid-coated iron oxide nanoparticles for targeting drug resistance in mycobacteria.

    PubMed

    Padwal, Priyanka; Bandyopadhyaya, Rajdip; Mehra, Sarika

    2014-12-23

    The emergence of drug resistance is a major problem faced in current tuberculosis (TB) therapy, representing a global health concern. Mycobacterium is naturally resistant to most drugs due to export of the latter outside bacterial cells by active efflux pumps, resulting in a low intracellular drug concentration. Thus, development of agents that can enhance the effectiveness of drugs used in TB treatment and bypass the efflux mechanism is crucial. In this study, we present a new nanoparticle-based strategy for enhancing the efficacy of existing drugs. To that end, we have developed poly(acrylic acid) (PAA)-coated iron oxide (magnetite) nanoparticles (PAA-MNPs) as efflux inhibitors and used it together with rifampicin (a first line anti-TB drug) on Mycobacterium smegmatis. PAA-MNPs of mean diameter 9 nm interact with bacterial cells via surface attachment and are then internalized by cells. Although PAA-MNP alone does not inhibit cell growth, treatment of cells with a combination of PAA-MNP and rifampicin exhibits a synergistic 4-fold-higher growth inhibition compared to rifampicin alone. This is because the combination of PAA-MNP and rifampicin results in up to a 3-fold-increased accumulation of rifampicin inside the cells. This enhanced intracellular drug concentration has been explained by real-time transport studies on a common efflux pump substrate, ethidium bromide (EtBr). It is seen that PAA-MNP increases the accumulation of EtBr significantly and also minimizes the EtBr efflux in direct proportion to the PAA-MNP concentration. Our results thus illustrate that the addition of PAA-MNP with rifampicin may bypass the innate drug resistance mechanism of M. smegmatis. This generic strategy is also found to be successful for other anti-TB drugs, such as isoniazid and fluoroquinolones (e.g., norfloxacin), only when stabilized, coated nanoparticles (such as PAA-MNP) are used, not PAA or MNP alone. We hence establish coated nanoparticles as a new class of efflux

  9. Synthesis of interpenetrating network hydrogel from poly(acrylic acid-co-hydroxyethyl methacrylate) and sodium alginate: modeling and kinetics study for removal of synthetic dyes from water.

    PubMed

    Mandal, Bidyadhar; Ray, Samit Kumar

    2013-10-15

    Several interpenetrating network (IPN) hydrogels were made by free radical in situ crosslink copolymerization of acrylic acid (AA) and hydroxy ethyl methacrylate in aqueous solution of sodium alginate. N,N'-methylenebisacrylamide (MBA) was used as comonomer crosslinker for making these crosslink hydrogels. All of these hydrogels were characterized by carboxylic content, FTIR, SEM, XRD, DTA-TGA and mechanical properties. Swelling, diffusion and network parameters of the hydrogels were studied. These hydrogels were used for adsorption of two important synthetic dyes, i.e. Congo red and methyl violet from water. Isotherms, kinetics and thermodynamics of dye adsorption by these hydrogels were also studied.

  10. TRPA1 is activated by direct addition of cysteine residues to the N-hydroxysuccinyl esters of acrylic and cinnamic acids.

    PubMed

    Sadofsky, Laura R; Boa, Andrew N; Maher, Sarah A; Birrell, Mark A; Belvisi, Maria G; Morice, Alyn H

    2011-01-01

    The nociceptor TRPA1 is thought to be activated through covalent modification of specific cysteine residues on the N terminal of the channel. The precise mechanism of covalent modification with unsaturated carbonyl-containing compounds is unclear, therefore by examining a range of compounds which can undergo both conjugate and/or direct addition reactions we sought to further elucidate the mechanism(s) whereby TRPA1 can be activated by covalent modification. Calcium signalling was used to determine the mechanism of activation of TRPA1 expressed in HEK293 cells with a series of related compounds which were capable of either direct and/or conjugate addition processes. These results were confirmed using physiological recordings with isolated vagus nerve preparations. We found negligible channel activation with chemicals which could only react with cysteine residues via conjugate addition such as acrylamide, acrylic acid, and cinnamic acid. Compounds able to react via either conjugate or direct addition, such as acrolein, methyl vinyl ketone, mesityl oxide, acrylic acid NHS ester, cinnamaldehyde and cinnamic acid NHS ester, activated TRPA1 in a concentration dependent manner as did compounds only capable of direct addition, namely propionic acid NHS ester and hydrocinnamic acid NHS ester. These compounds failed to activate TRPV1 expressed in HEK293 cells or mock transfected HEK293 cells. For molecules capable of direct or conjugate additions, the results suggest for the first time that TRPA1 may be activated preferentially by direct addition of the thiol group of TRPA1 cysteines to the agonist carbonyl carbon of α,β-unsaturated carbonyl-containing compounds.

  11. Magnetic Solid-Phase Extraction Based on β-Cyclodextrins/Acrylic Acid Modified Magnetic Gelatin for Determination of Moxidectin in Milk Samples.

    PubMed

    Shang, Yinzhu; Luo, Jing; Wang, Peng; Zhao, Xiaoya; Ye, Cheng; Guo, Shaofei

    2016-01-01

    β-Cyclodextrins/acrylic acid modified magnetic gelatin was prepared and then employed as the magnetic solid-phase extraction (MSPE) sorbent for extraction of moxidectin in milk samples. Due to the rigidity of hydrophobic cavity of β-cyclodextrins and carboxyl groups of acrylic acid, magnetic composites are prepared to form a complex with target molecules through various kinds of chemical reactions and then showed excellent extraction performance. This method exhibits the advantages of simplicity of implementation, short extraction time (5 min), low solvent consumption, and high extraction efficiency. A rapid, simple, and effective method for the analysis of moxidectin in milk samples was established by MSPE coupled with liquid chromatography-fluorescence detection. The limit of detection was 0.1 ng·mL(-1) and the recoveries from milk samples were in the range of 93.8%-112.5%. The relative standard deviation was not higher than 6.4%. In conclusion, magnetic solid-phase extraction is a simple and robust preconcentration technique that can be coupled to other analytical methods for the quantitative determination of target molecules in complex samples. PMID:27437160

  12. Copolymeric hexyl acrylate-methacrylic acid microspheres - surface vs. bulk reactive carboxyl groups. Coulometric and colorimetric determination and analytical applications for heterogeneous microtitration.

    PubMed

    Stelmach, Emilia; Maksymiuk, Krzysztof; Michalska, Agata

    2016-10-01

    Copolymeric acrylate microspheres were prepared from hexyl acrylate using different amounts of methacrylic acid, resulting in a series of microspheres of gradually changing properties. The distribution of carboxyl groups - between surface and bulk of microspheres was evaluated. Bulk reactive carboxyl groups were determined using reverse coulometric titration with H(+) ions, following hydroxide ions have been generated and allowed to react with microspheres in the first step. It was found that the number of reactive carboxyl groups available in copolymeric microspheres is lower compared to number of methacrylic acid units used for polymerization process. Moreover, there is correlation between the number of groups introduced and found to be reactive in microspheres. On the other hand, the number of surface reactive groups was proportional to the number of groups introduced in course of polymerization. Thus, the surface reactive groups can be used as reagent, in novel heterogeneous microtitration procedure, in which a constant number of microspheres of different carboxyl groups contents is introduced to the sample to react with the analyte. The applicability of novel proposed method was tested on the example of Ni(2+) determination. PMID:27474305

  13. Poly (Acrylamide-co-Acrylic Acid) Hydrogel Induced by Glow-Discharge Electrolysis Plasma and Its Adsorption Properties for Cationic Dyes

    NASA Astrophysics Data System (ADS)

    Yu, Jie; Yang, Gege; Pan, Yuanpei; Lu, Quanfang; Yang, Wu; Gao, Jinzhang

    2014-08-01

    In this paper, poly (acrylamide-co-acrylic acid) (P(AM-co-AA)) hydrogel was prepared in an aqueous solution by using glow-discharge electrolysis plasma (GDEP) induced copolymerization of acrylamide (AM) and acrylic acid (AA), in which N,N'-methylenebisacrylamide (MBA) was used as a crosslinker. A mechanism for the synthesis of P(AM-co-AA) hydrogel was proposed. To optimize the synthesis condition, the following parameters were examined in detail: the discharge voltage, discharge time, the content of the crosslinker, and the mass ratio of AM to AA. The results showed that the optimum pH range for cationic dyes removal was found to be 5.0-10.0. The P(AM-co-AA) hydrogel exhibits a very high adsorption potential and the experimental adsorption capacities for Crystal violet (CV) and Methylene blue (MB) were 2974.3 mg/g and 2303.6 mg/g, respectively. The adsorption process follows a pseudo-second-order kinetic model. In addition, the adsorption mechanism of P(AM-co-AA) hydrogel for cationic dyes was also discussed.

  14. Magnetic Solid-Phase Extraction Based on β-Cyclodextrins/Acrylic Acid Modified Magnetic Gelatin for Determination of Moxidectin in Milk Samples

    PubMed Central

    Shang, Yinzhu; Wang, Peng; Zhao, Xiaoya; Ye, Cheng; Guo, Shaofei

    2016-01-01

    β-Cyclodextrins/acrylic acid modified magnetic gelatin was prepared and then employed as the magnetic solid-phase extraction (MSPE) sorbent for extraction of moxidectin in milk samples. Due to the rigidity of hydrophobic cavity of β-cyclodextrins and carboxyl groups of acrylic acid, magnetic composites are prepared to form a complex with target molecules through various kinds of chemical reactions and then showed excellent extraction performance. This method exhibits the advantages of simplicity of implementation, short extraction time (5 min), low solvent consumption, and high extraction efficiency. A rapid, simple, and effective method for the analysis of moxidectin in milk samples was established by MSPE coupled with liquid chromatography-fluorescence detection. The limit of detection was 0.1 ng·mL−1 and the recoveries from milk samples were in the range of 93.8%–112.5%. The relative standard deviation was not higher than 6.4%. In conclusion, magnetic solid-phase extraction is a simple and robust preconcentration technique that can be coupled to other analytical methods for the quantitative determination of target molecules in complex samples. PMID:27437160

  15. Synthesis and magnetic heating characteristics of thermoresponsive poly (N-isopropylacrylamide-co-acrylic acid)/nano Fe3O4 nanparticles

    NASA Astrophysics Data System (ADS)

    Thu Trang Mai, Thi; Le, Thi Hong Phong; Pham, Hong Nam; Do, Hung Manh; Phuc Nguyen, Xuan

    2014-12-01

    In this work the synthesis of thermo-sensitive polymer coated magnetic nanoparticles and their inductive heating have been studied. Poly (N-isopropylacrylamide-co-acrylic acid) (NA) polymers were first synthesized by emulsion polymerization of poly(N-isopropylacrylamide) (NIP) in water and followed by encapsulating magnetic nanoparticles (MNPs). As increasing the concentration of acrylic acid (AA), the lower critical solution temperature (LCST) increased, so that with 150% of AA (molar ratio) the LCST reached 42 °C, which is close to the temperature of hyperthermia treatment. Magnetization and ac susceptibility measurements were conducted to depict some characteristics of the NIP-MNPs and NA-MNPs that are related with the loss power. Attempts to analyze the rate of magnetic inductive heating were performed to show the Brownian relaxation origin of additional heat source created by the magnetite nanoparticles capped with thermosensitive polymers. Our results suggest that these thermo-sensitive polymer-coated magnetic nanoparticles show a potential for hyperthermia and drug delivery application.

  16. Iron-Based Redox Polymerization of Acrylic Acid for Direct Synthesis of Hydrogel/Membranes, and Metal Nanoparticles for Water Treatment

    PubMed Central

    Hernández, Sebastián; Papp, Joseph K.; Bhattacharyya, Dibakar

    2014-01-01

    Functionalized polymer materials with ion exchange groups and integration of nano-structured materials is an emerging area for catalytic and water pollution control applications. The polymerization of materials such as acrylic acid often requires persulfate initiator and a high temperature start. However, is generally known that metal ions accelerate such polymerizations starting from room temperature. If the metal is properly selected, it can be used in environmental applications adding two advantages simultaneously. This paper deals with this by polymerizing acrylic acid using iron as accelerant and its subsequent use for nanoparticle synthesis in hydrogel and PVDF membranes. Characterizations of hydrogel, membranes and nanoparticles were carried out with different techniques. Nanoparticles sizes of 30–60 nm were synthesized. Permeability and swelling measurements demonstrate an inverse relationship between hydrogel mesh size (6.30 to 8.34 nm) and membrane pores (222 to 110 nm). Quantitative reduction of trichloroethylene/chloride generation by Fe/Pd nanoparticles in hydrogel/membrane platforms was also performed. PMID:24954975

  17. Synthesis and characterization of antigenic influenza A M2e protein peptide-poly(acrylic) acid bioconjugate and determination of toxicity in vitro

    PubMed Central

    Kilinc, Yasemin Budama; Akdeste, Zeynep Mustafaeva; Koc, Rabia Cakir; Bagirova, Melahat; Allahverdiyev, Adil

    2014-01-01

    The influenza A virus is a critical public health problem that causes epidemics and pandemics, and occurs widely all over the world. Various vaccines against the virus have not provided a solution to the problem. Different approaches, particularly M2e peptide–based vaccines, are available for developing universal vaccines against influenza A. However, it is important to select a suitable carrier to obtain an effective vaccine. Accordingly, studies on the usage of various carriers are ongoing. Particularly, polymer-based carriers have gained importance due to both drug delivery and adjuvant effects. Therefore, bioconjugate of the M2e protein peptide from the influenza A virus covalent bonded with poly(acrylic) acid was synthesized in our study for the first time. The characterization was performed using size-exclusion chromatography and fluorescence spectroscopy; subsequently, it was found that the bioconjugate of the examined lower doses (0.05 and 0.5 mg/ml) have no toxic effects on human cell lines. These results suggest that, in the future, the poly(acrylic) acid bioconjugate of the M2e peptide should be studied in vivo for universal vaccine development against the influenza A virus. PMID:25482080

  18. Evaluation of the mucosal irritation potency of co-spray dried Amioca/poly(acrylic acid) and Amioca/Carbopol 974P mixtures.

    PubMed

    Adriaens, E; Ameye, D; Dhondt, M M M; Foreman, P; Remon, J P

    2003-03-26

    The purpose of this study was to evaluate the biocompatibility of different Amioca/poly(acrylic acid) and Amioca/Carbopol 974P co-spray dried mixtures with an alternative mucosal irritation test using slugs. The irritation potential of the mixtures was measured by the amount of mucus produced during a repeated 30-min contact period. Additionally, membrane damage was assessed by measuring the protein and enzyme release from the body wall of slugs after treatment. All the Amioca/poly(acrylic acid) co-spray dried mixtures (50:50 and 25:75 ratios) induced slight irritation of the mucosal tissue as was demonstrated by the significantly increased mucus production however no increased protein and enzyme release was detected. Co-spray dried Amioca/Carbopol 974P mixtures containing 40% and more Carbopol 974P demonstrated a significantly higher mucus production and release of cytosolic LDH, indicating membrane damage. The total mucus production of the slugs treated with the co-spray dried mixtures containing up to 20% Carbopol 974P was significantly higher compared to the blank slugs. However, these mixtures induced no membrane damage since no additional effect on the protein release and no enzyme release was detected. By co-spray drying up to 20% Carbopol 974P could be incorporated without showing a distinct sign of irritation. These mixtures can be considered as potentially safe bioadhesive carriers.

  19. Functional and surface-active membranes from poly(vinylidene fluoride)-graft-poly(acrylic acid) prepared via RAFT-mediated graft copolymerization.

    PubMed

    Ying, L; Yu, W H; Kang, E T; Neoh, K G

    2004-07-01

    Poly (vinylidene fluoride) (PVDF) with "living" poly (acrylic acid) (PAAc) side chains (PVDF-g-PAAc) was prepared by reversible addition-fragmentation chain transfer (RAFT)-mediated graft copolymerization of acrylic acid (AAc) with the ozone-pretreated PVDF. The chemical composition and structure of the copolymers were characterized by elemental analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The copolymer could be readily cast into pH-sensitive microfiltration (MF) membranes with enriched living PAAc graft chains on the surface (including the pore surfaces) by phase inversion in an aqueous medium. The surface composition of the membranes was determined by X-ray photoelectron spectroscopy. The morphology of the membranes was characterized by scanning electron microscopy. The pore size distribution of the membranes was found to be much more uniform than that of the corresponding membranes cast from PVDF-g-PAAc prepared by the "conventional" free-radical graft copolymerization process. Most important of all, the MF membranes with surface-tethered PAAc macro chain transfer agents, or the living membrane surfaces, could be further functionalized via surface-initiated block copolymerization with N-isopropylacrylamide (NIPAAM) to obtain the PVDF-g-PAAc-b-PNIPAAM MF membranes, which exhibited both pH- and temperature-dependent permeability to aqueous media. PMID:16459627

  20. Segregation of mass at the periphery of N -isopropylacrylamide-co-acrylic-acid microgels at high temperatures

    SciTech Connect

    Hyatt, John S.; Do, Changwoo; Hu, Xiaobo; Choi, Hong Sung; Kim, Jin Woong; Lyon, L. Andrew; Fernandez-Nieves, Alberto

    2015-09-29

    Here, we investigate poly(N-isopropylacrylamide) (pNIPAM) microgels randomly copolymerized with large mol % of protonated acrylic acid (AAc), finding that above the lower critical solution temperature the presence of the acid strongly disrupts pNIPAM's collapse, leading to unexpected new behavior at high temperatures. We see a dramatic increase in the ratio between the radius of gyration and the hydrodynamic radius above the theoretical value for homogeneous spheres, and a corresponding increase of the network length scale, which we attribute to the presence of a heterogeneous polymer distribution that forms due to frustration of pNIPAM's coil-to-globule transition by the AAc. Finally, we analyze this phenomenon using a Debye-Bueche-like scattering contribution as opposed to the Lorentzian term often used, interpreting the results in terms of mass segregation at the particle periphery.

  1. Time-resolved EPR investigation of potential model systems for acrylate polymer main chain radicals based on esters of Kemp's tri-acid.

    PubMed

    Lebedeva, Natalia V; Gorelik, Elena V; Magnus-Aryitey, Damaris; Hill, Terence E; Forbes, Malcolm D E

    2009-05-14

    Methyl esters of Kemp's tri-acid and cyclohexanetricarboxylic acid are structurally similar to acrylate polymers, having the same functionalities and stereoregularities as poly(methylmethacrylate) and poly(methylacrylate), respectively. The photochemistry and free radicals from these model systems have been studied using time-resolved electron paramagnetic resonance spectroscopy with laser flash photolysis at 248 nm. Chemically induced electron spin polarization from the triplet mechanism (net emission) is observed. Well-resolved spectra are obtained at all temperatures for the model system radicals, which are determined to be in the slow motion condition, that is, there is no interconversion of chair conformations. The temperature dependence of the spectra is minimal; some hyperfine lines shift as the temperature increases, but without much broadening. Density functional theory calculations are presented and discussed in support of the experimental data.

  2. Ab Initio Calculations of Possible γ-Gauche Effects in the 13C-NMR for Methine and Carbonyl Carbons in Precise Polyethylene Acrylic Acid Copolymers

    SciTech Connect

    Alam, Todd

    2013-07-29

    The impacts of local polymer chain conformations on the methine and carbonyl 13C-NMR chemical shifts for polyethylene acrylic acid p(E-AA) copolymers were predicted using ab initio methods. Using small molecular cluster models, the magnitude and sign of the γ-gauche torsional angle effect, along with the impact of local tetrahedral structure distortions near the carbonyl group, on the 13C-NMR chemical shifts were determined. These 13C-NMR chemical shift variations were compared to the experimental trends observed for precise p(E-AA) copolymers as a function acid group spacing and degree of zinc-neutralization in the corresponding p(E-AA) ionomers. These ab initio calculations address the future ability of 13C-NMR chemical shift variations to provide information about the local chain conformations in p(E-AA) copolymer materials.

  3. Self-Organization of Polystyrene-b-polyacrylic Acid (PS-b-PAA) Monolayer at the Air/Water Interface: A Process Driven by the Release of the Solvent Spreading.

    PubMed

    Guennouni, Zineb; Cousin, Fabrice; Fauré, Marie-Claude; Perrin, Patrick; Limagne, Denis; Konovalov, Oleg; Goldmann, Michel

    2016-03-01

    We present an in situ structural study of the surface behavior of PS-b-PAA monolayers at the air/water interface at pH 2, for which the PAA blocks are neutral and using N,N-dimethyformamide (DMF) as spreading solvent. The surface pressure versus molecular area isotherm shows a perfectly reversible pseudoplateau over several cycles of compression/decompression. The width of such plateau enlarges when increasing temperature, conversely to what is classically observed in the case of an in-plane first order transition. We combined specular neutron reflectivity (SNR) experiments with contrast variation to solve the profile of each block perpendicular to the surface with grazing-incidence small-angle scattering (GISAXS) measurements to determine the in-plane structure of the layer. SNR experiments showed that both PS and PAA blocks remain adsorbed on the surface for all surface pressure probed. A correlation peak at Q(xy)* = 0.021 Å(-1) is evidenced by GISAXS at very low surface pressure which intensity first increases on the plateau. When compressing further, its intensity decays while Q(xy)* is shifted toward low Q(xy). The peak fully disappears at the end of the plateau. These results are interpreted by the formation of surface aggregates induced by DMF molecules at the surface. These DMF molecules remain adsorbed within the PS core of the aggregates. Upon compression, they are progressively expelled from the monolayer, which gives rise to the pseudoplateau on the isotherm. The intensity of the GISAXS correlation peak is set by the amount of DMF within the monolayer as it vanishes when all DMF molecules are expelled. This result emphizes the role of the solvent in Langmuir monolayer formed by amphiphilic copolymers which hydrophobic and hydrophilic parts are composed by long polymer chains.

  4. The Acrylation of Glycerol: a Precursor to Functionalized Lipids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Didecanoylacryloylglycerol was synthesized from decanoic and acrylic acids and glycerol using K2O as catalyst. This reaction was carried out in hexane in a closed stainless steel reactor at 200°C for 5h. The reactants were added in a 1:3:4 glycerol:decanoic acid:acrylic acid molar ratio. The resu...

  5. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate.

    PubMed

    Barbu, Eugen; Verestiuc, Liliana; Iancu, Mihaela; Jatariu, Anca; Lungu, Adriana; Tsibouklis, John

    2009-06-01

    Nanoparticulate hybrid polymeric hydrogels (10-70 nm) have been obtained via the radical-induced co-polymerization of acrylic acid-functionalized chitosan with either N-isopropylacrylamide or 2-hydroxyethyl methacrylate, and the materials have been investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. Studies on the effects of network structure upon swelling properties, adhesiveness to substrates that mimic mucosal surfaces and biodegradability, coupled with in vitro drug release investigations employing ophthalmic drugs with differing aqueous solubilities, have identified nanoparticle compositions for each of the candidate drug molecules. The hybrid nanoparticles combine the temperature sensitivity of N-isopropylacrylamide or the good swelling characteristics of 2-hydroxyethyl methacrylate with the susceptibility of chitosan to lysozyme-induced biodegradation. PMID:19433871

  6. The use of dielectric spectroscopy for the characterisation of the precipitation of hydrophobically modified poly(acrylic-acid) with divalent barium ions.

    PubMed

    Christensen, Peter Vittrup; Keiding, Kristian

    2009-12-01

    The use of dielectric spectroscopy as a monitor for coagulation processes was investigated. Hydrophobically modified poly(acrylic-acid) polymers were used as model macromolecules and coagulated with barium ions. The coagulation process was quantified using a photometric dispersion analyser, thereby serving as a point of reference for the dielectric spectroscopy. It was found that the hydrophobic modification increased the dosage of barium needed to obtain complete coagulation, whereas the dosage required to initiate coagulation was lowered. The coagulation of the polymer samples caused the relaxation time of the measured dielectric dispersion to increase, and this parameter was found to be a good indicator of the formation of polymer aggregates. The magnitude of the dielectric dispersion decreased as a function of barium dosage, but when coagulation was initiated an increase was observed. The observed agreement between the onset of coagulation and the changes in the dielectric dispersion shows the potential use of dielectric spectroscopy for the characterisation of coagulation processes. PMID:19751938

  7. A comparative study on the graft copolymerization of acrylic acid onto rayon fibre by a ceric ion redox system and a γ-radiation method.

    PubMed

    Kaur, Inderjeet; Kumar, Raj; Sharma, Neelam

    2010-10-13

    Functionalization of rayon fibre has been carried out by grafting acrylic acid (AAC) both by a chemical method using a Ce(4+)-HNO(3) redox initiator and by a mutual irradiation (γ-rays) method. The reaction conditions affecting the grafting percentage have been optimized for both methods, and the results are compared. The maximum percentage of grafting (50%) by the chemical method was obtained utilizing 18.24 × 10(-3) moles/L of ceric ammonium nitrate (CAN), 39.68 × 10(-2) moles/L of HNO(3), and 104.08 × 10(-2) moles/L of AAc in 20 mL of water at 45°C for 120 min. For the radiation method, the maximum grafting percentage (60%) was higher, and the product was obtained under milder reaction conditions using a lower concentration of AAc (69.38 × 10(-2) moles/L) in 10 mL of water at an optimum total dose of 0.932 kGy. Swelling studies showed higher swelling for the grafted rayon fibre in water (854.54%) as compared to the pristine fibre (407%), while dye uptake studies revealed poor uptake of the dye (crystal violet) by the grafted fibre in comparison with the pristine fibre. The graft copolymers were characterized by IR, TGA, and scanning electron micrographic methods. Grafted fibre, prepared by the radiation-induced method, showed better thermal behaviour. Comparison of the two methods revealed that the radiation method of grafting of acrylic acid onto rayon fibre is a better method of grafting in comparison with the chemical method.

  8. A new inorganic-organic composite coagulant, consisting of polyferric sulphate (PFS) and polyacrylamide (PAA).

    PubMed

    Moussas, P A; Zouboulis, A I

    2009-08-01

    Currently, research is focused on the synthesis of new composite coagulants, which are constituted of both inorganic and organic materials. In this paper, the development of relevant reagents was investigated, by combining the inorganic pre-polymerised iron-based coagulant Polyferric Sulphate (PFS) with an organic, non-ionic polymer (Polyacrylamide, PAA) under different PAA/Fe (mg/l) and OH/Fe molar ratios. Moreover, the new reagents were characterised in terms of typical properties, stability and morphological analysis (XRD, FTIR, SEM). Their coagulation performance, when treating low or high turbid kaolin-humic acid suspensions, was also investigated, whereas the applied coagulation mechanisms were discussed by using the Photometric Dispersion Analysis (PDA) analysis. The results show that the new coagulation reagents present improved properties, including increased effective polymer species concentration, and they exhibit very good stability. The respective tests using PDA confirmed that the predominant coagulation mechanism of PFS-PAA is the bridge formation mechanism. Coagulation experiments in low or high turbid kaolin-humic acid suspensions reveal that the novel composite reagent PFS-PAA exhibits better coagulation performance, when compared with simple PFS, in terms of zeta-potential reduction, turbidity and organic matter removal and residual iron concentration. PMID:19560180

  9. In vivo kinetic analysis of the penicillin biosynthesis pathway using PAA stimulus response experiments.

    PubMed

    Deshmukh, Amit T; Verheijen, Peter J T; Maleki Seifar, Reza; Heijnen, Joseph J; van Gulik, Walter M

    2015-11-01

    In this study we combined experimentation with mathematical modeling to unravel the in vivo kinetic properties of the enzymes and transporters of the penicillin biosynthesis pathway in a high yielding Penicillium chrysogenum strain. The experiment consisted of a step response experiment with the side chain precursor phenyl acetic acid (PAA) in a glucose-limited chemostat. The metabolite data showed that in the absence of PAA all penicillin pathway enzymes were expressed, leading to the production of a significant amount of 6-aminopenicillanic acid (6APA) as end product. After the stepwise perturbation with PAA, the pathway produced PenG within seconds. From the extra- and intracellular metabolite measurements, hypotheses for the secretion mechanisms of penicillin pathway metabolites were derived. A dynamic model of the penicillin biosynthesis pathway was then constructed that included the formation and transport over the cytoplasmic membrane of pathway intermediates, PAA and the product penicillin-G (PenG). The model parameters and changes in the enzyme levels of the penicillin biosynthesis pathway under in vivo conditions were simultaneously estimated using experimental data obtained at three different timescales (seconds, minutes, hours). The model was applied to determine changes in the penicillin pathway enzymes in time, calculate fluxes and analyze the flux control of the pathway. This led to a reassessment of the in vivo behavior of the pathway enzymes and in particular Acyl-CoA:Isopenicillin N Acyltransferase (AT).

  10. NGAP: A (Brief) Update PaaS, IaaS, Onbording, and the Future

    NASA Technical Reports Server (NTRS)

    McLaughlin, Brett; Pawloski, Andrew

    2016-01-01

    NASA ESDIS has charged the EED2 program with delivering a NASA-compliant, secure, cloud-based platform for application hosting. More than just a move to the cloud, this has forced us to examine all aspects of application hosting, from resource management to system administration, patching to monitoring, deployment to multiple environments. The result of this mandate is NGAP, the NASA General Application Platform. In this presentation, we will also discuss the various applications we are supporting and targeting, and their architectures including NGAPs move to support both PaaS and IaaS architectures.

  11. [Study on preparation of the pH sensitive hydroxyethyl chitin/poly (acrylic acid) hydrogel and its drug release property].

    PubMed

    Zhao, Yu; Chen, Guohua; Sun, Mingkun; Jin, Zhitao; Gao, Congjie

    2006-04-01

    Hydroxyethyl chitin (HECH) is a water soluble chitin derivative made by etherification of chitin, ethylene chlorohydrin was used as etherification reagent in this reaction. A novel interpenetrating polymer network (IPN) composed of HECH/PAA was prepared. The IR spectra confirmed that HECH/PAA was formed through chemical bond interaction. The sensitivity of this hydrogel to temperature and pH was studied. The swelling ratio of this hydrogel in artificial intestinal juice is much greater than that in artificial gastric juice. The IPN hydrogel exhibited a typical pH-sensitivity, and its degree of swelling ratio increased with the increase of temperature. The sustained-release drug system of Dichlofenac potassium was prepared by using HECH/PAA as the drug carrier. The release experiment showed a perfect release behavior in artificial intestinal juice. This IPN is expected to be used as a good drug delivery system of enteric medicine. PMID:16706361

  12. Comparison of the toxicity of the peracetic acid formulations Wofasteril(c) E400, E250 and Lspez to Daphnia magna with emphasis on the effect of hydrogen peroxide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercial peracetic acid (PAA) formulations are acidic mixtures of PAA, hydrogen peroxide (H2O2), acetic acid (AA), H2O and stabilizers to maintain equilibrium of the concentrations. Different PAA formulations show diverse PAA/H2O2 ratios, leading to potentially different toxicities at the same con...

  13. Effect of sodium hypochlorite and peracetic acid on the surface roughness of acrylic resin polymerized by heated water for short and long cycles

    PubMed Central

    Sczepanski, Felipe; Sczepanski, Claudia Roberta Brunnquell; Berger, Sandrine Bittencourt; Consani, Rafael Leonardo Xediek; Gonini-Júnior, Alcides; Guiraldo, Ricardo Danil

    2014-01-01

    Objective: To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). Materials and Methods: The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. Results: There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. Conclusion: It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness. PMID:25512737

  14. Microbial reduction in wastewater treatment using Fe(3+) and Al(3+) coagulants and PAA disinfectant.

    PubMed

    Pradhan, Surendra K; Kauppinen, Ari; Martikainen, Kati; Pitkänen, Tarja; Kusnetsov, Jaana; Miettinen, Ilkka T; Pessi, Matti; Poutiainen, Hannu; Heinonen-Tanski, Helvi

    2013-12-01

    Wastewater is an important source of pathogenic enteric microorganisms in surface water and a major contaminating agent of drinking water. Although primary and secondary wastewater treatments reduce the numbers of microorganisms in wastewater, significant numbers of microbes can still be present in the effluent. The aim of this study was to test the feasibility of tertiary treatment for municipal wastewater treatment plants (WWTPs) using PIX (FeCl3) or PAX (AlCl3) coagulants and peracetic acid (PAA) the disinfectant to reduce microbial load in effluent. Our study showed that both PIX and PAX efficiently reduced microbial numbers. PAA disinfection greatly reduced the numbers of culturable indicator microorganisms (Escherichia coli, intestinal enterococci, F-specific RNA coliphages and somatic DNA coliphages). In addition, pathogenic microorganisms, thermotolerant Campylobacter, Salmonella and norovirus GI, were successfully reduced using the tertiary treatments. In contrast, clostridia, Legionella, rotavirus, norovirus GII and adenovirus showed better resistance against PAA compared to the other microorganisms. However, interpretation of polymerase chain reaction (PCR) analysis results will need further studies to clarify the infectivity of the pathogenic microbes. In conclusion, PIX and PAX flocculants followed by PAA disinfectant can be used as a tertiary treatment for municipal WWTP effluents to reduce the numbers of indicator and pathogenic microorganisms.

  15. A study of the swelling and model protein release behaviours of radiation-formed poly(N-vinyl 2-pyrrolidone-co-acrylic acid) hydrogels

    NASA Astrophysics Data System (ADS)

    Wang, David; Hill, David J. T.; Rasoul, Firas; Whittaker, Andrew K.

    2011-02-01

    Hydrogels were prepared from poly(acrylic acid-co-N-vinyl pyrrolidone), poly(AA-co-VP) and mixtures of poly(AA-co-VP) and poly(ethylene oxide), PEO, by gamma radiolysis of aqueous solutions of the AA and VP monomers containing ethylene glycol dimethacrylate, EGDMA, as crosslinker and PEO. The AA/VP composition range of the poly(AA-co-VP) was XAA 0.7-0.9. The swelling behaviours of the hydrogels from the dry state were investigated in water (pH 6.5) and 50 mM 4-(2-hydroxyethyl)piperazine-1-ethylsulfonic acid buffer, HEPES buffer, at pH 7.4 and 295 K. The effects of poly(AA-co-VP) composition, crosslinker mole fraction and the presence of PEO on the equilibrium swelling ratio for the gels was examined. The kinetics of the release of a model protein, horseradish peroxidase, HRP, from the hydrogels in water were also studied at 295 K.

  16. Star-shaped polymers of bio-inspired algae core and poly(acrylamide) and poly(acrylic acid) as arms in dissolution of silica/silicate.

    PubMed

    Chauhan, Kalpana; Patiyal, Priyanka; Chauhan, Ghanshyam S; Sharma, Praveen

    2014-06-01

    Silica, in natural waters (due to weathering of rocks) decreases system performance in water processing industry due to scaling. In view of that, the present work involves the synthesis of novel green star shaped additives of algae core (a bio-inspired material as diatom maintains silicic acid equilibrium in sea water) as silica polymerization inhibitors. Star shaped materials with bio-inspired core and poly(acrylamide) [poly(AAm)] and poly(acrylic acid) [poly(AAc)] arms were synthesized by economical green approach. The proficiency was evaluated in 'mini lab' scale for the synthesized APAAm (Algae-g-poly(AAm)) and APAAc (Algae-g-poly(AAc)) dendrimers (star shaped) in colloidal silica mitigation/inhibition at 35 °C and 55 °C. Synthesized dendrimers were equally proficient in silica inhibition at 12 h and maintains ≥450 ppm soluble silica. However, APAAm dendrimers of generation 0 confirmed better results (≈300 ppm) in contrast to APAAc dendrimers in silica inhibition at 55 °C. Additionally, dendrimers also worked as a nucleator for heterogeneous polymerization to inhibit silica homo-polymerization. APAAm dendrimer test set showed no silica deposit for more than 10 days of inhibition. EDX characterization results support nucleator mechanism with Si content of 6.97%-10.98% by weight in silica deposits (SiO2-APAAm dendrimer composites).

  17. Star-shaped polymers of bio-inspired algae core and poly(acrylamide) and poly(acrylic acid) as arms in dissolution of silica/silicate.

    PubMed

    Chauhan, Kalpana; Patiyal, Priyanka; Chauhan, Ghanshyam S; Sharma, Praveen

    2014-06-01

    Silica, in natural waters (due to weathering of rocks) decreases system performance in water processing industry due to scaling. In view of that, the present work involves the synthesis of novel green star shaped additives of algae core (a bio-inspired material as diatom maintains silicic acid equilibrium in sea water) as silica polymerization inhibitors. Star shaped materials with bio-inspired core and poly(acrylamide) [poly(AAm)] and poly(acrylic acid) [poly(AAc)] arms were synthesized by economical green approach. The proficiency was evaluated in 'mini lab' scale for the synthesized APAAm (Algae-g-poly(AAm)) and APAAc (Algae-g-poly(AAc)) dendrimers (star shaped) in colloidal silica mitigation/inhibition at 35 °C and 55 °C. Synthesized dendrimers were equally proficient in silica inhibition at 12 h and maintains ≥450 ppm soluble silica. However, APAAm dendrimers of generation 0 confirmed better results (≈300 ppm) in contrast to APAAc dendrimers in silica inhibition at 55 °C. Additionally, dendrimers also worked as a nucleator for heterogeneous polymerization to inhibit silica homo-polymerization. APAAm dendrimer test set showed no silica deposit for more than 10 days of inhibition. EDX characterization results support nucleator mechanism with Si content of 6.97%-10.98% by weight in silica deposits (SiO2-APAAm dendrimer composites). PMID:24681378

  18. Preparation, properties and biological application of pH-sensitive poly(ethylene oxide) (PEO) hydrogels grafted with acrylic acid(AAc) using gamma-ray irradiation

    NASA Astrophysics Data System (ADS)

    Nho, Young Chang; Mook Lim, Youn; Moo Lee, Young

    2004-09-01

    pH-sensitive hydrogels were studied as a drug carrier for the protection of insulin from the acidic environment of the stomach before releasing it in the small intestine. In this study, hydrogels based on poly(ethylene oxide) (PEO) networks grafted with acrylic acid (AAc) were prepared via a two-step process. PEO hydrogels were prepared by γ-ray irradiation, and then grafting by AAc monomer onto the PEO hydrogels with the subsequent irradiation (radiation dose: 5-20 kGy, dose rate: 2.15 kGy/h). These grafted hydrogels showed a pH-sensitive swelling behavior. The grafted hydrogels were used as a carrier for the drug delivery systems for the controlled release of insulin. The in vitro drug release behaviors of these hydrogels were examined by quantification analysis with a UV/VIS spectrophotometer. Insulin was loaded into freeze-dried hydrogels (7 mm×3 mm×2.5 mm) and administrated orally to healthy and diabetic Wistar rats. The oral administration of insulin-loaded hydrogels to Wistar rats decreased the blood glucose levels obviously for at least 4 h due to the absorption of insulin in the gastrointestinal tract.

  19. Separation of copper ions from iron ions using PVA-g-(acrylic acid/N-vinyl imidazole) membranes prepared by radiation-induced grafting.

    PubMed

    Ajji, Zaki; Ali, Ali M

    2010-01-15

    Acrylic acid (AAc), N-vinyl imidazole (Azol) and their binary mixtures were graft copolymerized onto poly(vinyl alcohol) membranes using gamma irradiation. The ability of the grafted membranes to separate Cu ions from Fe ions was investigated with respect to the grafting yield and the pH of the feed solution. The data showed that the diffusion of copper ions from the feed compartment to the receiver compartment depends on the grafting yield of the membranes and the pH of the feed solution. To the contrary, iron ions did not diffuse through the membranes of all grafting yields. However, a limited amount of iron ions diffused in strong acidic medium. This study shows that the prepared membranes could be considered for the separation of copper ions from iron ions. The temperature of thermal decomposition of pure PVA-g-AAc/Azol membrane, PVA-g-AAc/Azol membrane containing copper ions, and PVA-g-AAc/Azol membrane containing iron ions were determined using TGA analyzer. It was shown that the presence of Cu and Fe ions increases the decomposition temperature, and the membranes bonded with iron ions are more stable than those containing copper ions. PMID:19836882

  20. Control of corona composition and morphology in aggregates of mixtures of PS-b-PAA and PS-b-P4VP diblock copolymers: effects of pH and block length.

    PubMed

    Vyhnalkova, Renata; Müller, Axel H E; Eisenberg, Adi

    2014-05-01

    The corona compositions and morphologies in aggregates of mixtures of amphiphilic polystyrene-block-poly(acrylic acid) (PS-b-PAA) and polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) diblock copolymers are influenced by controllable assembly parameters such as the hydrophilic block length and solution pH. The morphologies and corona compositions of the aggregates were investigated by transmission electron microscopy and electrophoretic mobility, respectively. When mineral acids or bases are present during aggregate formation, they can exert a strong influence on the corona composition. Morphology changes were also seen with changing pH, as well as changes in corona composition, specifically for vesicles. Because of complications introduced by the presence of ions, the general hypothesis that the external corona of the vesicles is composed of the longer chains, while the shorter chains form the inner corona, which is valid only in mixtures containing only nonionic chains without any additives (no acids or bases) or within a well-defined narrow pH range. In addition to the numerical block lengths and the pH, the solubility of the hydrophilic blocks can also influence the morphology and as well as the interfacial composition of vesicles; as the numerically longer chains become less soluble, they can contract and move to the interior, while the numerically shorter but more soluble chains go to the external corona. A remarkable morphological feature of the pH continuum is that for some compositions vesicles are observed in four distinct pH regions, separated by pH ranges in which other morphologies dominate. The effect of pH and microion content on coil dimensions of the PVP and PAA chains in the block copolymers is most likely responsible for the observed behavior.

  1. Acrylate Systemic Contact Dermatitis.

    PubMed

    Sauder, Maxwell B; Pratt, Melanie D

    2015-01-01

    Acrylates, the 2012 American Contact Dermatitis Society allergen of the year, are found in a range of products including the absorbent materials within feminine hygiene pads. When fully polymerized, acrylates are nonimmunogenic; however, if not completely cured, the monomers can be potent allergens.A 28-year-old woman is presented, who had her teeth varnished with Isodan (Septodont, Saint-Maur-des-Fossés, France) containing HEMA (2-hydroxyethyl methacrylate) with no initial reaction. Approximately 1 month later, the patient developed a genital dermatitis secondary to her feminine hygiene pads. The initial reaction resolved, but 5 months later, the patient developed a systemic contact dermatitis after receiving a second varnishing.The patient was dramatically patch test positive to many acrylates. This case demonstrates a reaction to likely unpolymerized acrylates within a feminine hygiene pad, as well as broad cross-reactivity or cosensitivity to acrylates, and possibly a systemic contact dermatitis with systemic re-exposure to unpolymerized acrylates.

  2. Interactions between lead-zirconate titanate, polyacrylic acid, and polyvinyl butyral in ethanol and their influence on electrophoretic deposition behavior.

    PubMed

    Kuscer, Danjela; Bakarič, Tina; Kozlevčar, Bojan; Kosec, Marija

    2013-02-14

    Electrophoretic deposition (EPD) is an attractive method for the fabrication of a few tens of micrometer-thick piezoelectric layers on complex-shape substrates that are used for manufacturing high-frequency transducers. Niobium-doped lead-zirconate titanate (PZT Nb) particles were stabilized in ethanol using poly(acrylic acid) (PAA). With Fourier-transform infrared spectroscopy (FT-IR), we found that the deprotonated carboxylic group from the PAA is coordinated with the metal in the perovskite PZT Nb structure, resulting in a stable ethanol-based suspension. The hydroxyl group from the polyvinyl butyral added into the suspension to prevent the formation of cracks in the as-deposited layer did not interact with the PAA-covered PZT Nb particles. PVB acts as a free polymer in ethanol-based suspensions. The electrophoretic deposition of micro- and nanometer-sized PZT Nb particles from ethanol-based suspensions onto electroded alumina substrates was attempted in order to obtain uniform, crack-free deposits. The interactions between the PZT Nb particles, the PAA, and the PVB in ethanol will be discussed and related to the properties of the suspensions, the deposition yield and the morphology of the as-deposited PZT Nb thick film.

  3. Controlling the Mesostructure Formation within the Shell of Novel Cubic/Hexagonal Phase Cetyltrimethylammonium Bromide-Poly(acrylamide-acrylic acid) Capsules for pH Stimulated Release.

    PubMed

    Tangso, Kristian J; Patel, Hetika; Lindberg, Seth; Hartley, Patrick G; Knott, Robert; Spicer, Patrick T; Boyd, Ben J

    2015-11-11

    The self-assembly of ordered structures in mixtures of oppositely charged surfactant and polymer systems has been exploited in various cleaning and pharmaceutical applications and continue to attract much interest since their discovery in the late twentieth century. The ability to control the electrostatic and hydrophobic interactions that dictate the formation of liquid crystalline phases in these systems is advantageous in manipulation of structure and rendering them responsive to external stimuli. Nanostructured capsules comprised of the cationic surfactant, cetyltrimethylammonium bromide (CTAB), and the diblock copolymer poly(acrylamide-acrylic acid) (PAAm-AA) were prepared to assess their potential as pH responsive nanomaterials. Crossed-polarizing light microscopy (CPLM) and small-angle X-ray scattering (SAXS) identified coexisting Pm3n cubic and hexagonal phases at the surfactant-polymer interface. The hydrophobic and electrostatic interactions between the oppositely charged components were studied by varying temperature and solution pH, respectively, and were found to influence the liquid crystalline nanostructure formed. The lattice parameter of the mesophases and the fraction of cubic phase in the system decreased upon heating. Acidic conditions resulted in the loss of the highly ordered structures due to protonation of the carboxylic acid group, and subsequent reduction of attractive forces previously present between the oppositely charged molecules. The rate of release of the model hydrophilic drug, Rhodamine B (RhB), from nanostructured macro-sized capsules significantly increased when the pH of the solution was adjusted from pH 7 to pH 2. This allowed for immediate release of the compound of interest "on demand", opening new options for structured materials with increased functionality over typical layer-by-layer capsules. PMID:26457761

  4. Controlling the Mesostructure Formation within the Shell of Novel Cubic/Hexagonal Phase Cetyltrimethylammonium Bromide-Poly(acrylamide-acrylic acid) Capsules for pH Stimulated Release.

    PubMed

    Tangso, Kristian J; Patel, Hetika; Lindberg, Seth; Hartley, Patrick G; Knott, Robert; Spicer, Patrick T; Boyd, Ben J

    2015-11-11

    The self-assembly of ordered structures in mixtures of oppositely charged surfactant and polymer systems has been exploited in various cleaning and pharmaceutical applications and continue to attract much interest since their discovery in the late twentieth century. The ability to control the electrostatic and hydrophobic interactions that dictate the formation of liquid crystalline phases in these systems is advantageous in manipulation of structure and rendering them responsive to external stimuli. Nanostructured capsules comprised of the cationic surfactant, cetyltrimethylammonium bromide (CTAB), and the diblock copolymer poly(acrylamide-acrylic acid) (PAAm-AA) were prepared to assess their potential as pH responsive nanomaterials. Crossed-polarizing light microscopy (CPLM) and small-angle X-ray scattering (SAXS) identified coexisting Pm3n cubic and hexagonal phases at the surfactant-polymer interface. The hydrophobic and electrostatic interactions between the oppositely charged components were studied by varying temperature and solution pH, respectively, and were found to influence the liquid crystalline nanostructure formed. The lattice parameter of the mesophases and the fraction of cubic phase in the system decreased upon heating. Acidic conditions resulted in the loss of the highly ordered structures due to protonation of the carboxylic acid group, and subsequent reduction of attractive forces previously present between the oppositely charged molecules. The rate of release of the model hydrophilic drug, Rhodamine B (RhB), from nanostructured macro-sized capsules significantly increased when the pH of the solution was adjusted from pH 7 to pH 2. This allowed for immediate release of the compound of interest "on demand", opening new options for structured materials with increased functionality over typical layer-by-layer capsules.

  5. Radiation grafting of pH-sensitive acrylic acid and 4-vinyl pyridine onto nylon-6 using one- and two-step methods

    NASA Astrophysics Data System (ADS)

    Ortega, Alejandra; Alarcón, Darío; Muñoz-Muñoz, Franklin; Garzón-Fontecha, Angélica; Burillo, Guillermina

    2015-04-01

    Acrylic acid (AAc) and 4-vinyl pyridine (4VP) were γ-ray grafted onto nylon-6 (Ny6) films via pre-irradiation oxidative method. These monomers were grafted using a one-step method to render Ny6-g-(AAc/4VP). A two-step or sequential method was used to render (Ny6-g-AAc)-g-4VP. Random copolymer branches were obtained when the grafting was carried out via one-step method using the two monomers together. The two-step method was applied to graft chains of 4VP on both Ny6 substrate and previously grafted AAc chains (Ny6-g-AAc). The two types of binary copolymers synthesized were characterized to determine the amount of grafted polymers, the thermal behavior (DSC and TGA), the surface composition (XPS), and the pH responsiveness. In the two-step process, it is possible to achieve a higher graft yield, better control of the amount of each monomer, good reversibility in the swelling/deswelling process and shorter time to achieve equilibrium swelling.

  6. Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells

    PubMed Central

    Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

    2016-01-01

    Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of −22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration. PMID:27164090

  7. Retention of heavy metal ions on comb-type hydrogels based on acrylic acid and 4-vinylpyridine, synthesized by gamma radiation

    NASA Astrophysics Data System (ADS)

    González-Gómez, Roberto; Ortega, Alejandra; Lazo, Luz M.; Burillo, Guillermina

    2014-09-01

    Two novel comb-type hydrogels based on pH-sensitive monomers (acrylic acid (AAc) and 4-vinylpyridine (4VP) were synthesized by gamma radiation. The systems were as follows: a) comb-type hydrogels of an AAc network followed by grafting of 4VP ((net-PAAc)-g-4VP) and b) comb-type hydrogels of an AAc network grafted onto polypropylene (PP) followed by grafting of 4VP (net-(PP-g-AAc)-g-4VP). The equilibrium isotherms and kinetics were evaluated for copper and zinc ions in aqueous solutions. The Zn(II) retention obtained was 480 mg g-1 and 1086 mg g-1 for (net-PAAc)-g-4VP and net-(PP-g-AAc)-g-4VP, respectively. At concentrations as low as ppm, retention efficiencies of approximately 90% were achieved for Cu(II) on (net-PAAc)-g-4VP and for Zn(II) on net-(PP-g-AAc)-g-4VP. Desorption of the hydrogels was also studied, and the results indicated that they can be used repeatedly in aqueous solutions. For both systems, the adsorption of Cu(II) and Zn(II) obeyed the Freundlich model, indicating heterogeneous sorption, and the retention process occurred by chemisorption. The sorption process follows a pseudo-second-order model.

  8. Effects of added surfactant on swelling and molecular transport in drug-loaded tablets based on hydrophobically modified poly(acrylic acid).

    PubMed

    Knöös, Patrik; Wahlgren, Marie; Topgaard, Daniel; Ulvenlund, Stefan; Piculell, Lennart

    2014-08-14

    A combination of NMR chemical shift imaging and self-diffusion experiments is shown to give a detailed molecular picture of the events that occur when tablets of hydrophobically modified poly(acrylic acid) loaded with a drug (griseofulvin) swell in water in the presence or absence of surfactant (sodium octylbenzenesulfonate). The hydrophobic substituents on the polymer bind and trap the surfactant molecules in mixed micelles, leading to a slow effective surfactant transport that occurs via a small fraction of individually dissolved surfactant molecules in the water domain. Because of the efficient binding of surfactant, the penetrating water is found to diffuse past the penetrating surfactant into the polymer matrix, pushing the surfactant front outward as the matrix swells. The added surfactant has little effect on the transport of drug because both undissolved solid drug and surfactant-solubilized drug function as reservoirs that essentially follow the polymer as it swells. However, the added surfactant nevertheless has a strong indirect effect on the release of griseofulvin, through the effect of the surfactant on the solubility and erosion of the polymer matrix. The surfactant effectively solubilizes the hydrophobically modified polymer, making it fully miscible with water, leading to a more pronounced swelling and a slower erosion of the polymer matrix.

  9. Poly(acrylic acid) Bridged Gadolinium Metal-Organic Framework-Gold Nanoparticle Composites as Contrast Agents for Computed Tomography and Magnetic Resonance Bimodal Imaging

    PubMed Central

    Tian, Chixia; Zhu, Liping; Lin, Feng; Boyes, Stephen G.

    2015-01-01

    Imaging contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) have received significant attention in the development of techniques for early-stage cancer diagnosis. Gadolinium (Gd) (III), which has seven unpaired electrons and a large magnetic moment, can dramatically influence the water proton relaxation and hence exhibits excellent MRI contrast. On the other hand, gold (Au), which has a high atomic number and high x-ray attenuation coefficient, is an ideal contrast agent candidate for x-ray based CT imaging. Gd metal organic framework (MOF) nanoparticles with tunable size, high Gd (III) loading and multivalency can potentially overcome the limitations of clinically utilized Gd chelate contrast agents. In this work, we report for the first time the integration of GdMOF nanoparticles with gold nanoparticles (AuNPs) for the preparation of a MRI/CT bimodal imaging agent. Highly stable hybrid GdMOF/AuNPs composites have been prepared by using poly(acrylic acid) as a bridge between the GdMOF nanoparticles and AuNPs. The hybrid nanocomposites were then evaluated in MRI and CT imaging. The results revealed high longitudinal relaxivity in MRI and excellent CT imaging performance. Therefore, these GdMOF/AuNPs hybrid nanocomposites potentially provide a new platform for the development of multi-modal imaging probes. PMID:26147906

  10. Metal ions doped chitosan-poly(acrylic acid) nanospheres: Synthesis and their application in simultaneously electrochemical detection of four markers of pancreatic cancer.

    PubMed

    Rong, Qinfeng; Feng, Feng; Ma, Zhanfang

    2016-01-15

    In this work, a one-pot method was designed to synthesize copper ions, cadmium ions, lead ions and zinc ions doped chitosan-poly(acrylic acid) nanospheres. Those nanospheres can not only produce independent electrochemical signals, but also react with glutaraldehyde (GA) to immobilize different labeled antibodies. Using the modified nanospheres as immunoprobes, a sandwich-type immunosensor was fabricated to simultaneous detection of four tumor markers (CEA, CA199, CA125 and CA242) of pancreatic cancer. This designed immunosensor exhibited good linear relationships in range from 0.1 to 100ng mL(-1) for CEA, 1 to 150UmL(-1) for CA199, CA125 and CA242, corresponding detection limits 0.02ng mL(-1), 0.4UmL(-1), 0.3UmL(-1) and 0.4UmL(-1), respectively. Meanwhile, the immunosensor was applied in analysis of clinical serum samples, whose results were well agreed with the enzyme-linked immunosorbent assay (ELISA), indicating that the proposed immunosensor gave a hope for the identification and validation of specific early cancer.

  11. Fabrication of magnetic hydroxypropyl cellulose-g-poly(acrylic acid) porous spheres via Pickering high internal phase emulsion for removal of Cu(2+) and Cd(2.).

    PubMed

    Zhu, Yongfeng; Zheng, Yian; Zong, Li; Wang, Feng; Wang, Aiqin

    2016-09-20

    A series of magnetic hydroxypropyl cellulose-g-poly(acrylic acid) porous spheres were prepared via O/W Pickering high internal phase emulsions (HIPEs) integrated precipitation polymerization. The structure and composition of modified Fe3O4 and porous structures were characterized by TEM, XRD, TGA and SEM. The results indicated that the silanized Fe3O4 can influence greatly the pore structure of magnetic porous sphere in addition to non-negligible impacts of the proportion of mixed solvent and co-surfactant. The adsorption experiment demonstrated that the adsorption equilibrium can be reached within 40min and the maximal adsorption capacity was 300.00mg/g for Cd(2+) and 242.72mg/g for Cu(2+), suggesting its fast adsorption kinetics and high adsorption capacity. After five adsorption-desorption cycles, no significant changes in the adsorption capacity were observed, suggesting its excellent reusability. The magnetic porous sphere can be easily separated from the solution and then find its potential as a recyclable material for highly efficient removal of heavy metals. PMID:27261748

  12. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    NASA Astrophysics Data System (ADS)

    Islas, Luisa; Ruiz, Juan-Carlos; Muñoz-Muñoz, Franklin; Isoshima, Takashi; Burillo, Guillermina

    2016-10-01

    Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from 60Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C1s and O1s content at the catheter's surface, revealed that the catheter's surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC's Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  13. Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells.

    PubMed

    Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

    2016-01-01

    Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of -22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration. PMID:27164090

  14. Photocurable bioactive bone cement based on hydroxyethyl methacrylate-poly(acrylic/maleic) acid resin and mesoporous sol gel-derived bioactive glass.

    PubMed

    Hesaraki, S

    2016-06-01

    This paper reports on strong and bioactive bone cement based on ternary bioactive SiO2-CaO-P2O5 glass particles and a photocurable resin comprising hydroxyethyl methacrylate (HEMA) and poly(acrylic/maleic) acid. The as-cured composite represented a compressive strength of about 95 MPa but it weakened during soaking in simulated body fluid, SBF, qua its compressive strength reached to about 20 MPa after immersing for 30 days. Biodegradability of the composite was confirmed by reducing its initial weight (~32%) as well as decreasing the molecular weight of early cured resin during the soaking procedure. The composite exhibited in vitro calcium phosphate precipitation in the form of nanosized carbonated hydroxyapatite, which indicates its bone bonding ability. Proliferation of calvarium-derived newborn rat osteoblasts seeded on top of the composite was observed during incubation at 37 °C, meanwhile, an adequate cell supporting ability was found. Consequently, it seems that the produced composite is an appropriate alternative for bone defect injuries, because of its good cell responses, high compressive strength and ongoing biodegradability, though more in vivo experiments are essential to confirm this assumption. PMID:27040248

  15. Covalent immobilization of redox enzyme on electrospun nonwoven poly(acrylonitrile-co-acrylic acid) nanofiber mesh filled with carbon nanotubes: a comprehensive study.

    PubMed

    Wang, Zhen-Gang; Ke, Bei-Bei; Xu, Zhi-Kang

    2007-07-01

    In this work, novel conductive composite nanofiber mesh possessing reactive groups was electrospun from solutions containing poly(acrylonitrile-co-acrylic acid) (PANCAA) and multi-walled carbon nanotubes (MWCNTs) for redoxase immobilization, assuming that the incorporated MWCNTs could behave as electrons transferor during enzyme catalysis. The covalent immobilization of catalase from bovine liver on the neat PANCAA nanofiber mesh or the composite one was processed in the presence of EDC/NHS. Results indicated that both the amount and activity retention of bound catalase on the composite nanofiber mesh were higher than those on the neat PANCAA nanofiber mesh, and the activity increased up to 42%. Kinetic parameters, K(m) and V(max), for the catalases immobilized on the composite nanofiber mesh were lower and higher than those on the neat one, respectively. This enhanced activity might be ascribed to either promoted electron transfer through charge-transfer complexes and the pi system of carbon nanotubes or rendered biocompatibility by modified MWCNTs. Furthermore, the immobilized catalases revealed much more stability after MWCNTs were incorporated into the polymer nanofiber mesh. However, there was no significant difference in optimum pH value and temperature, thermal stability and operational stability between these two immobilized preparations, while the two ones appeared more advantageous than the free in these properties. The effect of MWCNTs incorporation on another redox enzyme, peroxidase, was also studied and it was found that the activity increased by 68% in comparison of composite one with neat preparation. PMID:17171660

  16. Poly(acrylic acid)-regulated Synthesis of Rod-Like Calcium Carbonate Nanoparticles for Inducing the Osteogenic Differentiation of MC3T3-E1 Cells.

    PubMed

    Yang, Wei; Yao, Chenxue; Cui, Zhengyang; Luo, Dandan; Lee, In-Seop; Yao, Juming; Chen, Cen; Kong, Xiangdong

    2016-05-06

    Calcium carbonate, especially with nanostructure, has been considered as a good candidate material for bone regeneration due to its excellent biodegradability and osteoconductivity. In this study, rod-like calcium carbonate nanoparticles (Rod-CC NPs) with desired water dispersibility were achieved with the regulation of poly (acrylic acid). Characterization results revealed that the Rod-CC NPs had an average length of 240 nm, a width of 90 nm with an average aspect ratio of 2.60 and a negative ζ-potential of -22.25 ± 0.35 mV. The degradation study illustrated the nanoparticles degraded 23% at pH 7.4 and 45% at pH 5.6 in phosphate-buffered saline (PBS) solution within three months. When cultured with MC3T3-E1 cells, the Rod-CC NPs exhibited a positive effect on the proliferation of osteoblast cells. Alkaline phosphatase (ALP) activity assays together with the osteocalcin (OCN) and bone sialoprotein (BSP) expression observations demonstrated the nanoparticles could induce the differentiation of MC3T3-E1 cells. Our study developed well-dispersed rod-like calcium carbonate nanoparticles which have great potential to be used in bone regeneration.

  17. Poly(acrylic acid) Bridged Gadolinium Metal-Organic Framework-Gold Nanoparticle Composites as Contrast Agents for Computed Tomography and Magnetic Resonance Bimodal Imaging.

    PubMed

    Tian, Chixia; Zhu, Liping; Lin, Feng; Boyes, Stephen G

    2015-08-19

    Imaging contrast agents for magnetic resonance imaging (MRI) and computed tomography (CT) have received significant attention in the development of techniques for early stage cancer diagnosis. Gadolinium (Gd)(III), which has seven unpaired electrons and a large magnetic moment, can dramatically influence the water proton relaxation and hence exhibits excellent MRI contrast. On the other hand, gold (Au), which has a high atomic number and high X-ray attenuation coefficient, is an ideal contrast agent candidate for X-ray-based CT imaging. Gd metal-organic framework (MOF) nanoparticles with tunable size, high Gd(III) loading and multivalency can potentially overcome the limitations of clinically utilized Gd chelate contrast agents. In this work, we report for the first time the integration of GdMOF nanoparticles with gold nanoparticles (AuNPs) for the preparation of a MRI/CT bimodal imaging agent. Highly stable hybrid GdMOF/AuNPs composites have been prepared by using poly(acrylic acid) as a bridge between the GdMOF nanoparticles and AuNPs. The hybrid nanocomposites were then evaluated in MRI and CT imaging. The results revealed high longitudinal relaxivity in MRI and excellent CT imaging performance. Therefore, these GdMOF/AuNPs hybrid nanocomposites potentially provide a new platform for the development of multimodal imaging probes.

  18. One-Pot Synthesis of Hydrophilic Superparamagnetic Fe3O4/Poly(methyl methacrylate-acrylic acid) Composite Nanoparticles with High Magnetization.

    PubMed

    Ma, Shaohua; Lan, Fang; Yang, Qi; Xie, Liqin; Wu, Yao; Gu, Zhongwei

    2015-01-01

    Uniform superparamagnetic Fe3O4/poly(methyl methacrylate-acrylic acid) (P(MMA-AA)) composite nanoparticles with high saturation magnetization and good hydrophilicity were successfully and directly synthesized via a facile one-pot miniemulsion polymerization approach. The mixture of the ferrofluids, MMA and AA monomers, surfactants and initiator was co-sonicated and emulsified to prepare stable miniemulsion for polymerization. The as-prepared products were characterized by SEM, TEM, FT-IR, XRD, TGA and VSM. The results of SEM indicated that the morphology of the Fe3O4/P(MMA-AA) composite nanoparticles all assumed near spherical geometry with diameters about 60 nm, 60 nm, and 100 nm respectively corresponding to the weight ratios of Fe3O4 to MMA and AA at 1:8, 1:4, and 1:2. The TEM images implied that the Fe3O4/P(MMA-AA) composite nanoparticles showed a perfect core-shell structure with a polymeric shell of about 2 nm thickness and a core encapsulating uniform and close packed Fe3O4 nanoparticles. TGA and VSM showed that the Fe3O4/P(MMA-AA) composite nanoparticles with a maximum saturation magnetization up to 45 emu g(-1) corresponding to the magnetite content of 78% exhibited superparamagntism. The hydrophilic modification and the high saturation magnetization impart a promising potential for biomedical applications to the as-synthesized composite nanoparticles. PMID:26328359

  19. Strategy for identifying unknown hemoglobin adducts using adductome LC-MS/MS data: Identification of adducts corresponding to acrylic acid, glyoxal, methylglyoxal, and 1-octen-3-one.

    PubMed

    Carlsson, Henrik; Törnqvist, Margareta

    2016-06-01

    Electrophilic compounds have the ability to form adducts with nucleophilic sites in proteins and DNA in tissues, and thereby constitute risks for toxic effects. Adductomic approaches are developed for systematic screening of adducts to DNA and blood proteins, with the aim to detect unknown internal exposures to electrophiles. In a previous adductomic screening of adducts to N-terminals in hemoglobin, using LC-MS/MS, 19 unknown adducts were detected in addition to seven previously identified adducts. The present paper describes the identification of four of these unknown adducts, as well as the strategy used to identify them. Using LC-MS data from the screening, hypotheses about adduct identities were formulated: probable precursor electrophiles with matching molecular weights were suggested based on the molecular weights of the modifications and the retention times of the analytes, in combination with comparisons of theoretical Log P calculations and databases. Reference adducts were generated by incubation of blood samples with the hypothesized precursor electrophiles. The four identified precursor electrophiles, corresponding to the observed unknown adducts, were glyoxal, methylglyoxal, acrylic acid and 1-octen-3-one. Possible origins/exposure sources and toxicological information concerning the electrophilic precursors are discussed. The identified adducts could be explored as possible biomarkers for exposure. PMID:27046699

  20. Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating.

    PubMed

    Rivolo, Paola; Nisticò, Roberto; Barone, Fabrizio; Faga, Maria Giulia; Duraccio, Donatella; Martorana, Selanna; Ricciardi, Serena; Magnacca, Giuliana

    2016-08-01

    In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV-Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties. PMID:27157754

  1. Study of the adhesive properties versus stability/aging of hernia repair meshes after deposition of RF activated plasma polymerized acrylic acid coating.

    PubMed

    Rivolo, Paola; Nisticò, Roberto; Barone, Fabrizio; Faga, Maria Giulia; Duraccio, Donatella; Martorana, Selanna; Ricciardi, Serena; Magnacca, Giuliana

    2016-08-01

    In order to confer adhesive properties to commercial polypropylene (PP) meshes, a surface plasma-induced deposition of poly-(acrylic acid) (PPAA) is performed. Once biomaterials were functionalized, different post-deposition treatments (i.e. water washing and/or thermal treatments) were investigated with the aim of monitoring the coating degradation (and therefore the loss of adhesion) after 3months of aging in both humid/oxidant (air) and inert (nitrogen) atmospheres. A wide physicochemical characterization was carried out in order to evaluate the functionalization effectiveness and the adhesive coating homogeneity by means of static water drop shape analysis and several spectroscopies (namely, FTIR, UV-Visible and X-ray Photoemission Spectroscopy). The modification of the adhesion properties after post-deposition treatments as well as aging under different storage atmospheres were investigated by means of Atomic Force Microscopy (AFM) used in Force/Distance (F/D) mode. This technique confirms itself as a powerful tool for unveiling the surface adhesion capacity as well as the homogeneity of the functional coatings along the fibers. Results obtained evidenced that post-deposition treatments are mandatory in order to remove all oligomers produced during the plasma-treatment, whereas aging tests evidenced that these devices can be simply stored in presence of air for at least three months without a meaningful degradation of the original properties.

  2. Synthesis and high-efficiency methylene blue adsorption of magnetic PAA/MnFe2O4 nanocomposites

    NASA Astrophysics Data System (ADS)

    Wang, Wei; Ding, Zui; Cai, Minhan; Jian, Haitao; Zeng, Zhiqiao; Li, Feng; Liu, J. Ping

    2015-08-01

    MnFe2O4 nanoparticles and polyacrylic acid PAA/MnFe2O4 nanocomposites were synthesized by a hydrothermal method and ultrasonic mixing process. The obtained materials were characterized by XRD, FTIR, SEM, TEM, and VSM. XRD patterns indicate that the synthesized MnFe2O4 nanoparticles have a single cubic spinel phase. SEM images confirm the existence of three types of basic morphology of MnFe2O4 nanoparticles: octahedral, flower-like, and plate-like particles. High saturation magnetization Ms (up to 74.6 emu/g) of the as-synthesized MnFe2O4 nanoparticles was obtained. Experiments demonstrate that the variation of the hydrothermal reaction time does not remarkably affect the magnetic properties of MnFe2O4 nanoparticles. In PAA/MnFe2O4 nanocomposites, the coating of PAA leads to a slight decrease in magnetization of MnFe2O4 nanoparticles. Additionally, PAA coating greatly enhances the adsorption properties of MnFe2O4 nanoparticles for Methylene Blue (MB) dye. Especially, the removal efficiency reaches 96.3%. This research indicates that the as-synthesized PAA/MnFe2O4 nanocomposites exhibit excellent magnetic properties and can be taken as a promising adsorbent for removal of MB dye in industrial scale.

  3. Hygienisierung in der Fischzucht mittels Per-essigsäure (Disinfection of water with PAA: State of the investigations)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are very few therapeutic agents against aquaculture ectoparasites in Germany. Peracetic Acid (PAA) has been referred to as the best disinfective agent in the world, but it has not been used much here in aquaculture. We currently use this compound in ‘treatment crisis’ situations because ther...

  4. Mass-spectrometric investigation of ortho-hydroxynitrosoarenes and their rearrangement products - /beta/(2-cyanoaryl)acrylic acids

    SciTech Connect

    Terent'ev, P.B.; Rakhimi, M.I.; Stankevichus, A.P.; Kalandarishvili, A.G.; Bundel', Yu.G.

    1988-06-20

    Comparative analysis of the mass spectra of 2-hydroxy-1-nitrosonaphthalene, its benzo-substituted derivatives, 2-hydroxy-1-nitrosoanthracene, 2-hydroxy-1-nitrosophenanthrene, and also the products from their Beckmann rearrangement of the second kind, i.e., ortho-cyanocinnamic (benzocinnamic) acids, shows that the molecular ions of the ortho-nitrosohydroxyarenes formed under electron impact largely retain the topology of the initial molecule and do not undergo a Beckmann rearrangement of the second kind to an appreciable degree.

  5. Optical limiting response of multi-walled carbon nanotube-phthalocyanine nanocomposite in solution and when in poly (acrylic acid)

    NASA Astrophysics Data System (ADS)

    Sekhosana, Kutloano Edward; Nyokong, Tebello

    2016-08-01

    Bis{23-(3,4-di-yloxybenzoic acid)-(2(3), 9(10), 16(17), 23(24)-(hexakis-pyridin-3-yloxy phthalocyaninato)} dineodymium (III) acetate (3) is linked to amino-functionalized multi-walled carbon nanotubes (MWCNT) to form 3-MWCNT. Z-scan technique was employed to experimentally determine the nonlinear absorption coefficient from the open-aperture data. The limiting threshold values as low as 0.045 J cm-2 were found in solution. The conjugate (3-MWCNT) gave better optical limiting behavior than complex 3 alone.

  6. Phenylacetic acid catabolism and its transcriptional regulation in Corynebacterium glutamicum.

    PubMed

    Chen, Xi; Kohl, Thomas A; Rückert, Christian; Rodionov, Dmitry A; Li, Ling-Hao; Ding, Jiu-Yuan; Kalinowski, Jörn; Liu, Shuang-Jiang

    2012-08-01

    The industrially important organism Corynebacterium glutamicum has been characterized in recent years for its robust ability to assimilate aromatic compounds. In this study, C. glutamicum strain AS 1.542 was investigated for its ability to catabolize phenylacetic acid (PAA). The paa genes were identified; they are organized as a continuous paa gene cluster. The type strain of C. glutamicum, ATCC 13032, is not able to catabolize PAA, but the recombinant strain ATCC 13032/pEC-K18mob2::paa gained the ability to grow on PAA. The paaR gene, encoding a TetR family transcription regulator, was studied in detail. Disruption of paaR in strain AS 1.542 resulted in transcriptional increases of all paa genes. Transcription start sites and putative promoter regions were determined. An imperfect palindromic motif (5'-ACTNACCGNNCGNNCGGTNAGT-3'; 22 bp) was identified in the upstream regions of paa genes. Electrophoretic mobility shift assays (EMSA) demonstrated specific binding of PaaR to this motif, and phenylacetyl coenzyme A (PA-CoA) blocked binding. It was concluded that PaaR is the negative regulator of PAA degradation and that PA-CoA is the PaaR effector. In addition, GlxR binding sites were found, and binding to GlxR was confirmed. Therefore, PAA catabolism in C. glutamicum is regulated by the pathway-specific repressor PaaR, and also likely by the global transcription regulator GlxR. By comparative genomic analysis, we reconstructed orthologous PaaR regulons in 57 species, including species of Actinobacteria, Proteobacteria, and Flavobacteria, that carry PAA utilization genes and operate by conserved binding motifs, suggesting that PaaR-like regulation might commonly exist in these bacteria.

  7. Heterogeneously catalysed partial oxidation of acrolein to acrylic acid--structure, function and dynamics of the V-Mo-W mixed oxides.

    PubMed

    Kampe, Philip; Giebeler, Lars; Samuelis, Dominik; Kunert, Jan; Drochner, Alfons; Haass, Frank; Adams, Andreas H; Ott, Joerg; Endres, Silvia; Schimanke, Guido; Buhrmester, Thorsten; Martin, Manfred; Fuess, Hartmut; Vogel, Herbert

    2007-07-21

    The major objective of this research project was to reach a microscopic understanding of the structure, function and dynamics of V-Mo-(W) mixed oxides for the partial oxidation of acrolein to acrylic acid. Different model catalysts (from binary and ternary vanadium molybdenum oxides up to quaternary oxides with additional tungsten) were prepared via a solid state preparation route and hydrochemical preparation of precursors by spray-drying or crystallisation with subsequent calcination. The phase composition was investigated ex situ by XRD and HR-TEM. Solid state prepared samples are characterised by crystalline phases associated to suitable phase diagrams. Samples prepared from crystallised and spray-dried precursors show crystalline phases which are not part of the phase diagram. Amorphous or nanocrystalline structures are only found in tungsten doped samples. The kinetics of the partial oxidation as well as the catalysts' structure have been studied in situ by XAS, XRD, temperature programmed reaction and reduction as well as by a transient isotopic tracing technique (SSITKA). The reduction and re-oxidation kinetics of the bulk phase have been evaluated by XAS. A direct influence not only of the catalysts' composition but also of the preparation route is shown. Altogether correlations are drawn between structure, oxygen dynamics and the catalytic performance in terms of activity, selectivity and long-term stability. A model for the solid state behaviour under reaction conditions has been developed. Furthermore, isotope exchange experiments provided a closer image of the mechanism of the selective acrolein oxidation. Based on the in situ characterisation in combination with micro kinetic modelling a detailed reaction model which describes the oxygen exchange and the processes at the catalyst more precisely is discussed. PMID:17612723

  8. Radiation-grafting of thermo- and pH-responsive poly(N-vinylcaprolactam-co-acrylic acid) onto silicone rubber and polypropylene films for biomedical purposes

    NASA Astrophysics Data System (ADS)

    Ferraz, Caroline C.; Varca, Gustavo H. C.; Ruiz, Juan-Carlos; Lopes, Patricia S.; Mathor, Monica B.; Lugão, Ademar B.; Bucio, Emilio

    2014-04-01

    This work focuses on the effects of gamma-ray irradiation conditions on the stimuli-responsiveness of polypropylene (PP) films and silicone (SR) rubber substrates grafted with N-vinylcaprolactam (NVCL) and acrylic acid (AAc). PP films and SR rubber were modified by simultaneous polymerization and grafting of NVCL and AAc, using pre-irradiation oxidative method at a dose rate of 12.23 kGy h-1 and doses ranging from 5 to 70 kGy. NVCL and AAc solutions (1/1, v/v) at 50% monomer concentration (v/v) in toluene were added to the sample substrates, degassed, sealed and heated at 60 and 70 °C for 12 h. After grafting, the samples were soaked in ethanol and distilled water for 24 h successively, followed by drying under vacuum. Samples were characterized by FTIR-ATR, DSC and swelling measurements. Critical points (pH critical or LCST) of grafts were obtained in a pH-environment (pH ranges from 2.2 to 9) and in a thermo-environment (temperature ranges from 22 to 50 °C). Cytotoxicity evaluation was performed using fibroblast BALB/c 3T3 cells. The relationship between NVCL-co-AAc grafting and radiation dose was different for each substrate, PP and SR. At 50% NVCL/AAc concentration in toluene, grafting values were higher for SR than for PP. Despite the fact that PP-g-(NVCL-co-AAc) membrane presented a cytotoxic profile at the highest experimental concentration assayed, cytotoxicity evaluation revealed noncytotoxic profiles for the membranes synthesized highlighting their applications for biomedical purposes.

  9. Evaluation of CK2 inhibitor (E)-3-(2,3,4,5-tetrabromophenyl)acrylic acid (TBCA) in regulation of platelet function.

    PubMed

    Ryu, Si-Yun; Kim, Soochong

    2013-11-15

    Casein Kinase II (CK2) is a serine/threonine kinase which is expressed in platelets. Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a substrate of CK2 and antagonizes PI 3-kinase-mediated pathways by dephosphorylating phosphatidylinositol 3,4,5-triphosphate (PIP3). Since the role of CK2 and its signaling mechanism in platelet activation is not understood, we have examined whether CK2 plays an important role in agonist-induced platelet functional responses through the regulation of PI 3-kinase pathways by using a new class of highly selective CK2 inhibitor TBCA [(E)-3-(2,3,4,5-tetrabromophenyl)acrylic acid]. TBCA dose-dependently inhibited platelet aggregation and secretion induced by various agonists including 2-MeSADP, AYPGKF, SFLLRN, and CRP. Extent of platelet response inhibited by TBCA was similar to the extent of inhibition induced by PI 3-kinase inhibitors. CK2 regulated phosphorylation of PTEN as the inhibition of CK2 resulted in the inhibition of AYPGKF-induced PTEN phosphorylation. Agonist-induced thromboxane A2 (TxA2) generation and ERK phosphorylation were significantly inhibited by TBCA. TBCA also inhibited phosphorylation of PDK1, Akt, and GSK3β induced by AYPGKF. However, CK2 inhibition had no effect on AYPGKF-induced phosphorylation of PKC substrate plekstrin, demonstrating the selective action of TBCA through Gi-mediated PI 3-kinase pathways. Finally, platelet spreading on immobilized fibrinogen surface and clot retraction mediated by integrin αIIbβ3 signaling were significantly inhibited in the presence of TBCA. We conclude that CK2 plays a key role in platelet aggregation, secretion, TxA2 generation, and Akt and ERK phosphorylation, through the regulation of PI 3-kinase pathways. Moreover, CK2 is involved in αIIbβ3-mediated outside-in signaling in platelets. PMID:24140231

  10. Physicochemical properties of pH-controlled polyion complex (PIC) micelles of poly(acrylic acid)-based double hydrophilic block copolymers and various polyamines.

    PubMed

    Warnant, J; Marcotte, N; Reboul, J; Layrac, G; Aqil, A; Jerôme, C; Lerner, D A; Gérardin, C

    2012-05-01

    The physicochemical properties of polyion complex (PIC) micelles were investigated in order to characterize the cores constituted of electrostatic complexes of two oppositely charged polyelectrolytes. The pH-sensitive micelles were obtained with double hydrophilic block copolymers containing a poly(acrylic acid) block linked to a modified poly(ethylene oxide) block and various polyamines (polylysine, linear and branched polyethyleneimine, polyvinylpyridine, and polyallylamine). The pH range of micellization in which both components are ionized was determined for each polyamine. The resulting PIC micelles were characterized using dynamic light scattering and small-angle X-ray scattering experiments (SAXS). The PIC micelles presented a core-corona nanostructure with variable polymer density contrasts between the core and the corona, as revealed by the analysis of the SAXS curves. It was shown that PIC micelle cores constituted by polyacrylate chains and polyamines were more or less dense depending on the nature of the polyamine. It was also determined that the density of the cores of the PIC micelles depended strongly on the nature of the polyamine. These homogeneous cores were surrounded by a large hairy corona of hydrated polyethylene oxide block chains. Auramine O (AO) was successfully entrapped in the PIC micelles, and its fluorescence properties were used to get more insight on the core properties. Fluorescence data confirmed that the cores of such micelles are quite compact and that their microviscosity depended on the nature of the polyamine. The results obtained on these core-shell micelles allow contemplating a wide range of applications in which the AO probe would be replaced by various cationic drugs or other similarly charged species to form drug nanocarriers or new functional nanodevices.

  11. Heterogeneously catalysed partial oxidation of acrolein to acrylic acid--structure, function and dynamics of the V-Mo-W mixed oxides.

    PubMed

    Kampe, Philip; Giebeler, Lars; Samuelis, Dominik; Kunert, Jan; Drochner, Alfons; Haass, Frank; Adams, Andreas H; Ott, Joerg; Endres, Silvia; Schimanke, Guido; Buhrmester, Thorsten; Martin, Manfred; Fuess, Hartmut; Vogel, Herbert

    2007-07-21

    The major objective of this research project was to reach a microscopic understanding of the structure, function and dynamics of V-Mo-(W) mixed oxides for the partial oxidation of acrolein to acrylic acid. Different model catalysts (from binary and ternary vanadium molybdenum oxides up to quaternary oxides with additional tungsten) were prepared via a solid state preparation route and hydrochemical preparation of precursors by spray-drying or crystallisation with subsequent calcination. The phase composition was investigated ex situ by XRD and HR-TEM. Solid state prepared samples are characterised by crystalline phases associated to suitable phase diagrams. Samples prepared from crystallised and spray-dried precursors show crystalline phases which are not part of the phase diagram. Amorphous or nanocrystalline structures are only found in tungsten doped samples. The kinetics of the partial oxidation as well as the catalysts' structure have been studied in situ by XAS, XRD, temperature programmed reaction and reduction as well as by a transient isotopic tracing technique (SSITKA). The reduction and re-oxidation kinetics of the bulk phase have been evaluated by XAS. A direct influence not only of the catalysts' composition but also of the preparation route is shown. Altogether correlations are drawn between structure, oxygen dynamics and the catalytic performance in terms of activity, selectivity and long-term stability. A model for the solid state behaviour under reaction conditions has been developed. Furthermore, isotope exchange experiments provided a closer image of the mechanism of the selective acrolein oxidation. Based on the in situ characterisation in combination with micro kinetic modelling a detailed reaction model which describes the oxygen exchange and the processes at the catalyst more precisely is discussed.

  12. pH-Triggered release from surface-modified poly(lactic-co-glycolic acid) nanoparticles

    PubMed Central

    Häuser, Manuel; Langer, Klaus

    2015-01-01

    Summary Nanoparticles (NP) of poly(lactic-co-glycolic acid) (PLGA) represent a promising biodegradable drug delivery system. We suggest here a two-step release system of PLGA nanoparticles with a pH-tunable polymeric shell, providing an initial pH-triggered step, releasing a membrane-toxic cationic compound. PLGA nanoparticles are coated by polyelectrolytes using the layer-by-layer self-assembly technique, employing poly(acrylic acid) (PAA) as a pH-sensitive component and poly(diallyldimethylammonium chloride) (PDADMAC) as the releasable polycation. The pH during multilayer deposition plays a major role and influences the titration curve of the layer system. The pH-tunability of PAA is intensively investigated with regard to the pH region, in which the particle system becomes uncharged. The isoelectric point can be shifted by employing suitable deposition pH values. The release is investigated by quantitative 1H NMR, yielding a pH-dependent release curve. A release of PDADMAC is initiated by a decrease of the pH value. The released amount of polymer, as quantified by 1H NMR analysis, clearly depends on the pH value and thus on the state of deprotonation of the pH-sensitive PAA layer. Subsequent incubation of the nanoparticles with high concentrations of sodium chloride shows no further release and thus demonstrates the pH-driven release to be quantitative. PMID:26885463

  13. The influence of polymer topology on pharmacokinetics: differences between cyclic and linear PEGylated poly(acrylic acid) comb polymers.

    PubMed

    Chen, Bo; Jerger, Katherine; Fréchet, Jean M J; Szoka, Francis C

    2009-12-16

    Water-soluble polymers for the delivery of chemotherapeutic drugs passively target solid tumors as a consequence of reduced renal clearance and the enhanced permeation and retention (EPR) effect. Elimination of the polymers in the kidney occurs due to filtration through biological nanopores with a hydrodynamic diameter comparable to the polymer. Therefore we have investigated chemical features that may broadly be grouped as "molecular architecture" such as: molecular weight, chain flexibility, number of chain ends and branching, to learn how they impact polymer elimination. In this report we describe the synthesis of four pairs of similar molecular weight cyclic and linear polyacrylic acid polymers grafted with polyethylene glycol (23, 32, 65, 114 kDa) with low polydispersities using ATRP and "click" chemistry. The polymers were radiolabeled with (125)I and their pharmacokinetics and tissue distribution after intravenous injection were determined in normal and C26 adenocarcinoma tumored BALB/c mice. Cyclic polymers above the renal threshold of 30 kDa had a significantly longer elimination time (between 10 and 33% longer) than did the comparable linear polymer (for the 66 kDa cyclic polymer, t(1/2,beta)=35+/-2 h) and a greater area under the serum concentration versus time curve. This resulted in a greater tumor accumulation of the cyclic polymer than the linear polymer counterpart. Thus water-soluble cyclic comb polymers join a growing list of polymer topologies that show greatly extended circulation times compared to their linear counterparts and provide alternative polymer architecture for use as drug carriers.

  14. Preparation and characterization of hybrid pH-sensitive hydrogels of chitosan-co-acrylic acid for controlled release of verapamil.

    PubMed

    Ranjha, Nazar M; Ayub, Gohar; Naseem, Shahzad; Ansari, Muhammad Tayyab

    2010-10-01

    In the present work crosslinked hydrogels based on chitosan (CS) and acrylic acid (AA) were prepared by free radical polymerization with various feed compositions using N,N methylenebisacrylamide (MBA) as crosslinking agent. Benzoyl peroxide was used as catalyst. Fourier transform infrared spectra (FTIR) confirmed the formation of the crosslinked hydrogels. This hydrogel is formed due to electrostatic interaction between cationic groups in CS and anionic groups in AA. Prepared hydrogels were used for dynamic and equilibrium swelling studies. For swelling behavior, effect of pH, polymeric and monomeric compositions and degree of crosslinking were investigated. Swelling studies were performed in USP phosphate buffer solutions of varying pH 1.2, 5.5, 6.5 and 7.5. Results showed that swelling increased by increasing AA contents in structure of hydrogels in solutions of higher pH values. This is due to the presence of more carboxylic groups available for ionization. On the other hand by increasing the chitosan content swelling increased in a solution of acidic pH, but this swelling was not significant and it is due to ionization of amine groups present in the structure of hydrogel. Swelling decreased with increase in crosslinking ratio owing to tighter hydrogel structure. Porosity and sol-gel fraction were also measured. With increase in CS and AA contents porosity and gel fraction increased, whereas by increasing MBA content porosity decreased and gel fraction increased. Furthermore, diffusion coefficient (D) and the network parameters i.e., the average molecular weight between crosslinks (M(c)), polymer volume fraction in swollen state (V(2s)), number of repeating units between crosslinks (M(r)) and crosslinking density (q) were calculated using Flory-Rehner theory. Selected samples were loaded with a model drug verapamil. Release of verapamil depends on the ratios of CS/AA, degree of crosslinking and pH of the medium. The release mechanisms were studied by fitting

  15. Multifunctional electroactive electrospun nanofiber structures from water solution blends of PVA/ODA–MMT and poly(maleic acid-alt-acrylic acid): effects of Ag, organoclay, structural rearrangement and NaOH doping factors

    NASA Astrophysics Data System (ADS)

    Şimşek, Murat; Rzayev, Zakir M. O.; Bunyatova, Ulviya

    2016-06-01

    Novel multifunctional colloidal polymer nanofiber electrolytes were fabricated by green reactive electrospinning nanotechnology from various water solution/dispersed blends of poly (vinyl alcohol-co-vinyl acetate) (PVA)/octadecyl amine-montmorillonite (ODA–MMT) as matrix polymer nanocomposite and poly(maleic acid-alt-acrylic acid) (poly(MAc-alt-AA) and/or its Ag-carrying complex as partner copolymers. Polymer nanofiber electrolytes were characterized using FTIR, XRD, thermal (DSC, TGA–DTG), SEM, and electrical analysis methods. Effects of partner copolymers, organoclay, in situ generated silver nanoparticles (AgNPs), and annealing procedure on physical and chemical properties of polymer composite nanofibers were investigated. The electrical properties (resistance, conductivity, activation energy) of nanofibers with/without NaOH doping agent were also evaluated. This work presented a structural rearrangement of nanofiber mats by annealing via decarboxylation of anhydride units with the formation of new conjugated double bond sites onto partner copolymer main chains. It was also found that the semiconductor behaviors of nanofiber structures were essentially improved with increasing temperature and fraction of partner copolymers as well as presence of organoclay and AgNPs in nanofiber composite.

  16. Multifunctional electroactive electrospun nanofiber structures from water solution blends of PVA/ODA-MMT and poly(maleic acid-alt-acrylic acid): effects of Ag, organoclay, structural rearrangement and NaOH doping factors

    NASA Astrophysics Data System (ADS)

    Şimşek, Murat; Rzayev, Zakir M. O.; Bunyatova, Ulviya

    2016-06-01

    Novel multifunctional colloidal polymer nanofiber electrolytes were fabricated by green reactive electrospinning nanotechnology from various water solution/dispersed blends of poly (vinyl alcohol-co-vinyl acetate) (PVA)/octadecyl amine-montmorillonite (ODA-MMT) as matrix polymer nanocomposite and poly(maleic acid-alt-acrylic acid) (poly(MAc-alt-AA) and/or its Ag-carrying complex as partner copolymers. Polymer nanofiber electrolytes were characterized using FTIR, XRD, thermal (DSC, TGA-DTG), SEM, and electrical analysis methods. Effects of partner copolymers, organoclay, in situ generated silver nanoparticles (AgNPs), and annealing procedure on physical and chemical properties of polymer composite nanofibers were investigated. The electrical properties (resistance, conductivity, activation energy) of nanofibers with/without NaOH doping agent were also evaluated. This work presented a structural rearrangement of nanofiber mats by annealing via decarboxylation of anhydride units with the formation of new conjugated double bond sites onto partner copolymer main chains. It was also found that the semiconductor behaviors of nanofiber structures were essentially improved with increasing temperature and fraction of partner copolymers as well as presence of organoclay and AgNPs in nanofiber composite.

  17. Acrylic vessel cleaning tests

    SciTech Connect

    Earle, D.; Hahn, R.L.; Boger, J.; Bonvin, E.

    1997-02-26

    The acrylic vessel as constructed is dirty. The dirt includes blue tape, Al tape, grease pencil, gemak, the glue or residue form these tapes, finger prints and dust of an unknown composition but probably mostly acrylic dust. This dirt has to be removed and once removed, the vessel has to be kept clean or at least to be easily cleanable at some future stage when access becomes much more difficult. The authors report on the results of a series of tests designed: (a) to prepare typical dirty samples of acrylic; (b) to remove dirt stuck to the acrylic surface; and (c) to measure the optical quality and Th concentration after cleaning. Specifications of the vessel call for very low levels of Th which could come from tape residues, the grease pencil, or other sources of dirt. This report does not address the concerns of how to keep the vessel clean after an initial cleaning and during the removal of the scaffolding. Alconox is recommended as the cleaner of choice. This acrylic vessel will be used in the Sudbury Neutrino Observatory.

  18. Acrylic purification and coatings

    NASA Astrophysics Data System (ADS)

    Kuźniak, Marcin

    2011-04-01

    Radon (Rn) and its decay daughters are a well-known source of background in direct WIMP detection experiments, as either a Rn decay daughter or an alpha particle emitted from a thin inner surface layer of a detector could produce a WIMP-like signal. Different surface treatment and cleaning techniques have been employed in the past to remove this type of contamination. A new method of dealing with the problem has been proposed and used for a prototype acrylic DEAP-1 detector. Inner surfaces of the detector were coated with a layer of ultra pure acrylic, meant to shield the active volume from alphas and recoiling nuclei. An acrylic purification technique and two coating techniques are described: a solvent-borne (tested on DEAP-1) and solvent-less (being developed for the full scale DEAP-3600 detector).

  19. Acrylic purification and coatings

    SciTech Connect

    Kuzniak, Marcin

    2011-04-27

    Radon (Rn) and its decay daughters are a well-known source of background in direct WIMP detection experiments, as either a Rn decay daughter or an alpha particle emitted from a thin inner surface layer of a detector could produce a WIMP-like signal. Different surface treatment and cleaning techniques have been employed in the past to remove this type of contamination. A new method of dealing with the problem has been proposed and used for a prototype acrylic DEAP-1 detector. Inner surfaces of the detector were coated with a layer of ultra pure acrylic, meant to shield the active volume from alphas and recoiling nuclei. An acrylic purification technique and two coating techniques are described: a solvent-borne (tested on DEAP-1) and solvent-less (being developed for the full scale DEAP-3600 detector).

  20. Improved homopolymer separation to enable the application of 1H NMR and HPLC for the determination of the reaction parameters of the graft copolymerization of acrylic acid onto starch.

    PubMed

    Witono, Judy R; Marsman, Jan Henk; Noordergraaf, Inge-Willem; Heeres, Hero J; Janssen, Leon P B M

    2013-04-01

    Graft copolymers of starch with acrylic acid are a promising green, bio based material with many potential applications. The grafting of acrylic acid onto cassava starch in an aqueous medium initiated by Fenton's reagent has been studied. Common grafting result parameters are add-on (yield) and graft efficiency (selectivity). However, the analysis of the reaction products and an accurate determination of these parameters stand or fall with a complete separation of the entangled but ungrafted homopolymer from the grafted product. Therefore, this separation is the core of the newly developed analytical procedure. An appropriate solvent has been selected with dedicated testing from the range methanol, ethanol, acetone, dioxane, 2-propanol, and 1-propanol. Acetone showed the best performance in many respects. It has a high dissolving power for the homopolymer, as well as the highest yield of precipitation for the starch derivatives and it is the most economical in use. After the successful separation, the precipitated graft copolymers could be analyzed quantitatively by nuclear magnetic resonance. The liquid with homopolymer and unreacted monomer was analyzed by high pressure liquid chromatography. Proof of grafting has been found by FTIR and TGA analyses. The mass balance calculation shows a systematic error which appears fairly consistent: 18.0±2.5 wt%. This was used as a correction factor in the calculation of the grafting parameters but more importantly, it means that the method we developed has a high level of repeatability, in the order of 97%. PMID:23435285

  1. Synthesis of linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite as an adsorbent for removal of Pb(ΙΙ) from aqueous solutions.

    PubMed

    Irani, Maryam; Ismail, Hanafi; Ahmad, Zulkifli; Fan, Maohong

    2015-01-01

    The purpose of this work is to remove Pb(II) from the aqueous solution using a type of hydrogel composite. A hydrogel composite consisting of waste linear low density polyethylene, acrylic acid, starch, and organo-montmorillonite was prepared through emulsion polymerization method. Fourier transform infrared spectroscopy (FTIR), Solid carbon nuclear magnetic resonance spectroscopy (CNMR)), silicon(-29) nuclear magnetic resonance spectroscopy (Si NMR)), and X-ray diffraction spectroscope ((XRD) were applied to characterize the hydrogel composite. The hydrogel composite was then employed as an adsorbent for the removal of Pb(II) from the aqueous solution. The Pb(II)-loaded hydrogel composite was characterized using Fourier transform infrared spectroscopy (FTIR)), scanning electron microscopy (SEM)), and X-ray photoelectron spectroscopy ((XPS)). From XPS results, it was found that the carboxyl and hydroxyl groups of the hydrogel composite participated in the removal of Pb(II). Kinetic studies indicated that the adsorption of Pb(II) followed the pseudo-second-order equation. It was also found that the Langmuir model described the adsorption isotherm better than the Freundlich isotherm. The maximum removal capacity of the hydrogel composite for Pb(II) ions was 430mg/g. Thus, the waste linear low-density polyethylene-g-poly (acrylic acid)-co-starch/organo-montmorillonite hydrogel composite could be a promising Pb(II) adsorbent.

  2. A biocompatible calcium salt of hyaluronic acid grafted with polyacrylic acid.

    PubMed

    Nakagawa, Yoshiyuki; Nakasako, Satoshi; Ohta, Seiichi; Ito, Taichi

    2015-03-01

    We have synthesized hyaluronic acid (HA) grafted with polyacrylic acid (PAA) via controlled radical polymerization (CRP) in aqueous media. The grafted HA (HA-g-PAA) showed slow degradation by hyaluronidase compared with unmodified HA as a result of the steric hindrance produced by grafted PAA, and PAA was detached by hydrolysis and enzymatic degradation by lipase. It formed an insoluble salt immediately after mixing with Ca(2+) by the binding between grafted PAA and Ca(2+). Both HA-g-PAA and its salt showed good biocompatibility, especially to mesothelial cells in vitro. Finally, they were administered into mice subcutaneously and intraperitoneally. The residue of the material was observed 7 days after subcutaneous administration, while the material was almost cleared from the peritoneum 7 days after intraperitoneal administration with or without Ca(2+). HA-g-PAA is expected to be applicable to medical uses such as drug delivery in the peritoneum and for materials preventing peritoneal adhesion.

  3. Acrylic mechanical bond tests

    SciTech Connect

    Wouters, J.M.; Doe, P.J.

    1991-02-01

    The tensile strength of bonded acrylic is tested as a function of bond joint thickness. 0.125 in. thick bond joints were found to posses the maximum strength while the acceptable range of joints varied from 0.063 in. to almost 0.25 in. Such joints are used in the Sudbury Neutrino Observatory.

  4. Studies on the hydrolysis of biocompatible acrylic polymers having aspirin-moieties.

    PubMed

    Gu, Z W; Li, F M; Feng, X D; Voong, S T

    1983-01-01

    Both the homogeneous and heterogeneous hydrolysis of five new acrylic polymers having aspirin-moieties, i.e. polymers of beta-(acetylsalicylyloxy)ethyl methacrylate, beta-(acetylsalicylyloxy) propyl methacrylate,beta-(acetylsalicylyloxy) ethyl acrylate, beta-hydroxy-gamma-(acetylsalicylyloxy) propyl methacrylate, beta-hydroxy-gamma-(acetylsalicylyloxy) propyl acrylate were investigated in acidic or alkaline medium at 30 degrees C or 60 degrees C, respectively. It was observed that the chief hydrolyzed product is always aspirin with minor amount of salicylic acid.

  5. [Studies on primary aromatic amines (PAAs) migration from multi-layer plastic food packaging by HPLC method].

    PubMed

    Cwiek-Ludwicka, Kazimiera; Pawlicka, Marzena; Starski, Andrzej; Półtorak, Hanna; Karłowski, Kazimierz

    2011-01-01

    The aim of this study was to identify of primary aromatic amines (PAAs) and to determine their migration from plastic food packaging. The magnitude of the migration of these substances from plastic food packaging consists a base for the evaluation of their compliance with the requirements of EU legislation and hazard for human health taking into account their migration into food. The unprinted and printed multi-layer plastic packaging (laminates), domestic and imported, were examined in these studies. PAAs migration tests from the laminates into food simulant (3% acetic acid) was performed according to the appropriate procedures recommended in the EU for testing migration from food contact articles under standard conditions reflecting the real use of laminates (10 days, 40 degrees C) and under ,, worst case scenario" conditions (2 h, 70 degrees C). PAAs present in migration solutions were concentrated on SPE columns and then seven PAAs (aniline, 1,3-phenylenediamine, 2, 6-toluenediamine, 2,4-toluenediamine, 4,4'-oxydianiline, 4,4'-methylenedianiline and 3,3 '-dimethylbenzidyne) were identified and determined by previously validated HPLC-DAD method. Depending on the migration conditions the PAAs content was different. When the "worst case scenario" conditions were applied the migration of 4,4 '-methylenedianiline (4,4 '-MDA) ranged from below detection limit (LOD = 0.51 microg/kg) up to 9.86 microg/kg, and aniline was released in the range from below detection limit (LOD = 0,98 microg/kg) up to 7.04 microg/kg. In two laminate samples of eight examined, the sum of PAAs (aniline and 4,4'-MDA) was 13.32 microg/kg and 14.72 microg/kg showing that the permitted limit (10 microg/kg) was exceeded. In the standard conditions, the migration of aniline and 4,4'-MDA was significantly lower Regarding the carcinogenic potential of PAAs, the laminates causing the amines migration above the permitted limit should not be used as food packaging.

  6. Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate

    SciTech Connect

    Binder, Thomas; Erpelding, Michael; Schmid, Josef; Chin, Andrew; Sammons, Rhea; Rockafellow, Erin

    2015-04-10

    Conversion of Lignocellulosic Biomass to Ethanol and Butyl Acrylate. The purpose of Archer Daniels Midlands Integrated Biorefinery (IBR) was to demonstrate a modified acetosolv process on corn stover. It would show the fractionation of crop residue to distinct fractions of cellulose, hemicellulose, and lignin. The cellulose and hemicellulose fractions would be further converted to ethanol as the primary product and a fraction of the sugars would be catalytically converted to acrylic acid, with butyl acrylate the final product. These primary steps have been demonstrated.

  7. [Determination of 9 residual acrylic monomers in acrylic resins by gas chromatography-mass spectrometry coupled with microwave assisted extraction].

    PubMed

    Lai, Ying; Lin, Rui; Cai, Luxin; Ge, Xiuxiu; Huang, Changchun

    2012-01-01

    A reliable gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 9 residual acrylic monomers (methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl acrylate, butyl methacrylate, styrene, acrylic acid and methacrylic acid) in acrylic resins. Solid resin was precipitated with methanol after microwave assisted extraction with ethyl acetate for 30 min, and liquid resin was diluted with methanol directly. The nine acrylic monomers got a good separation within 20 min on a DB-WAX column. The limits of quantification (LOQs, S/N = 10) of the method were in the range of 1-10 mg/kg for liquid resin and 3-50 mg/kg for solid resin. The calibration curves were linear within 1-500 mg/L range with correlation coefficients above 0. 995. The recoveries ranged from 84.4% to 108.6% at five spiked levels. The sensitivity, recovery and selectivity of the method can fully meet the requirements of practical work.

  8. In vitro and in vivo evaluation of mucoadhesive microspheres prepared for the gastrointestinal tract using polyglycerol esters of fatty acids and a poly(acrylic acid) derivative.

    PubMed

    Akiyama, Y; Nagahara, N; Kashihara, T; Hirai, S; Toguchi, H

    1995-03-01

    Two types of polyglycerol ester of fatty acid (PGEF)-based microspheres were prepared: Carbopol 934P (CP)-coated microspheres (CPC-microspheres) and CP-dispersion microspheres (CPD-microspheres). Comparative studies on mucoadhesion were done with these microspheres and PGEF-based microspheres without CP (PGEF-microspheres). In an in vitro adhesion test, the CPD-microspheres adhered strongly to mucosa prepared from rat stomach and small intestine because each CP particle in the CPD-microsphere was hydrated and swelled with part of it remaining within the microsphere and part extending to the surface serving to anchor the microsphere to the mucus layer. The gastrointestinal transit patterns after administration of the CPD-microspheres and PGEF-microspheres to fasted rats were fitted to a model in which the microspheres are emptied from the stomach monoexponentially with a lag time and then transit through the small intestine at zero-order. Parameters obtained by curve fitting confirmed that the gastrointestinal transit time of the CPD-microspheres was prolonged compared with that of the PGEF-microspheres. MRT in the gastrointestinal tract was also prolonged after administration of the CPD-microspheres compared with that following the administration of the PGEF-microspheres.

  9. Acute toxicity of peracetic acid to fish

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA; also called peroxyacetic acid) is a stabilized mixture of acetic acid, hydrogen peroxide and water that does not leave dangerous residues in the environment when it breaks down as most compounds do. PAA is a promising disinfectant in the US aquaculture industry to control paras...

  10. pH effect of coagulation bath on the characteristics of poly(acrylic acid)-grafted and poly(4-vinylpyridine)-grafted poly(vinylidene fluoride) microfiltration membranes.

    PubMed

    Ying, Lei; Zhai, Guangqun; Winata, A Y; Kang, E T; Neoh, K G

    2003-09-15

    The poly(acrylic acid)-graft-poly(vinylidene fluoride) (PAAc-g-PVDF) and poly(4-vinylpyridine)-graft-poly(vinylidene fluoride) (P4VP-g-PVDF) copolymers were obtained by thermally induced molecular graft copolymerization of acrylic acid (AAc) and 4-vinylpyridine (4VP), respectively, with the ozone-pretreated poly(vinylidene fluoride) (PVDF) in N-methyl-2-pyrrolidone (NMP) solution. Microfiltration (MF) membranes were prepared from the respective copolymers by phase inversion in aqueous media. The effects of pH of the coagulation bath on the physicochemical and morphological characteristics of the membranes were investigated. The surface compositions of the membranes were determined by X-ray photoelectron spectroscopy (XPS). The surface graft concentration of the AAc polymer for the PAAc-g-PVDF MF membrane increased with decreasing pH value of the coagulation bath. Completely opposite pH-dependent behavior was observed for the surface graft concentration of the 4VP polymer in the P4VP-g-PVDF MF membranes. A substantial increase in mean pore size was observed for the PAAc-g-PVDF MF membranes cast in basic coagulation baths of increasing pH. In the case of the P4VP-g-PVDF MF membranes, a substantial increase in mean pore size was observed for membranes cast in low pH (acidic) baths. The permeation rate of aqueous solutions through the PAAc-g-PVDF and P4VP-g-PVDF MF membranes exhibited a reversible dependence on the pH of the solution, with the membranes cast near the neutral pH exhibiting the highest sensitivity to changes in permeate pH. PMID:12962674

  11. Growth inhibition of Aeromonas salmonicida and Yersinia ruckeri by disinfectants containing peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is an agent used for disinfection in aquaculture. PAA contributes to sustainable aquaculture, because it releases no harmful residue in the environment. However, there is lack of guideline about the effective application of different PAA products against various pathogens in p...

  12. PERI-ANESTHESIA ANAPHYLAXIS (PAA): WE STILL HAVE NOT STARTED POST-PAA TESTING FOR INCITING ANESTHESIA-RELATED ALLERGENS.

    PubMed

    Alshaeri, Taghreed; Gupta, Deepak; Nagabhushana, Ananthamurthy

    2016-02-01

    Anaphylaxis during anesthesia is uncommon. Diagnosis of peri-anesthesia anaphylaxis (PAA) requires anesthesia providers' vigilance for prompt diagnosis and treatment. In this case report, we present a challenging case with suspected PAA including its perioperative management, intensive care unit (ICU) course, and post-discharge follow-up. A 44-year-old female (body mass index = 26) presented for elective abdominal panniculectomy. Post-intubation, severe bronchospasm occurred that was non-responsive to nebulized albuterol and intravenous epinephrine. Continuous infusion of epinephrine was initiated. After aborting surgical procedure, the patient was transferred to ICU on continuous intravenous infusion of epinephrine. Venous blood sampling showed elevated troponin level. Echocardiography revealed ejection fraction of 25% suspicious of Takotsubo cardiomyopathy (mid cavitary variant). Tracheal extubation was only possible after three days. Subsequently, patient was discharged home with a cardiology follow-up appointment and a referral to an allergy specialist. Unfortunately at our institution (an academic university hospital in United States) along with neighboring institutions in near-by areas, the only allergy skin tests available are for local anesthetics and antibiotics, while neuromuscular blocking agents (NMBAs) cannot be tested (the suspected anaphylactic agent in our case was presumably rocuronium). In summary, PAA requires and responds to emergent diagnosis and immediate treatment; however there is still a long way to go to ensure post-PAA testing for inciting anesthesia-related allergens. PMID:27382817

  13. 21 CFR 177.1010 - Acrylic and modified acrylic plastics, semirigid and rigid.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylic and modified acrylic plastics, semirigid... Acrylic and modified acrylic plastics, semirigid and rigid. Semirigid and rigid acrylic and modified acrylic plastics may be safely used as articles intended for use in contact with food, in accordance...

  14. 21 CFR 177.1010 - Acrylic and modified acrylic plastics, semirigid and rigid.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylic and modified acrylic plastics, semirigid... Acrylic and modified acrylic plastics, semirigid and rigid. Semirigid and rigid acrylic and modified acrylic plastics may be safely used as articles intended for use in contact with food, in accordance...

  15. 21 CFR 177.1010 - Acrylic and modified acrylic plastics, semirigid and rigid.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acrylic and modified acrylic plastics, semirigid... Acrylic and modified acrylic plastics, semirigid and rigid. Semirigid and rigid acrylic and modified acrylic plastics may be safely used as articles intended for use in contact with food, in accordance...

  16. [Effect of acrylate industry wastes on the environment and the prevention of their harmful action].

    PubMed

    Tikhomirov, Iu P

    1991-01-01

    Acrylic and methacrylic++ acids and monomers as raw materials for production of polymers and copolymers are highly and extremely dangerous substances causing chronic intoxication. At low concentrations, acrylates and methacrylates++ have been found to produce not only systemic toxic, but embryotoxic effects. Manufacture of methacrylic++ and acrylic acids and monomers yields waste gases and waters that contain various acrylic compounds as impurities. The sewage treatment system introduced prevents the pollution of reservoirs with these compounds. High concentrations of acrylates and methacrylates are recorded in the sources of waste gases. It is required that fundamentally new waste--free technological processes for production of methacrylates++ and acrylates be designed and introduced and that the waste gas decontamination systems be improved in order to enhance the efficiency of measures to prevent environmental pollution.

  17. Constrained photophysics of partially and fully encapsulated charge transfer probe (E)-3-(4-Methylaminophenyl) acrylic acid methyl ester inside cyclodextrin nano-cavities: Evidence of cyclodextrins cavity dependent complex stoichiometry

    NASA Astrophysics Data System (ADS)

    Ghosh, Shalini; Jana, Sankar; Guchhait, Nikhil

    2011-12-01

    The polarity sensitive intra-molecular charge transfer (ICT) emission from (E)-3-(4-Methylaminophenyl) acrylic acid methyl ester (MAPAME) is found to show distinct changes once introduced into the nano-cavities of cyclodextrins in aqueous environment. Movement of the molecule from the more polar aqueous environment to the less polar, hydrophobic cyclodextrin interior is marked by the blue shift of the CT emission band with simultaneous fluorescence intensity enhancement. The emission spectral changes on complexation with the α- and β-CD show different stoichiometries as observed from the Benesi-Hildebrand plots. Fluorescence anisotropy and lifetime measurements were performed to probe the different behaviors of MAPAME in aqueous α- and β-CD solutions.

  18. [Treatment of acrylate wastewater by electrocatalytic reduction process].

    PubMed

    Yu, Li-Na; Song, Yu-Dong; Zhou, Yue-Xi; Zhu, Shu-Quan; Zheng, Sheng-Zhi; Ll, Si-Min

    2011-10-01

    High-concentration acrylate wastewater was treated by an electrocatalytic reduction process. The effects of the cation exchange membrane (CEM) and cathode materials on acrylate reduction were investigated. It indicated that the acrylate could be reduced to propionate acid efficiently by the electrocatalytic reduction process. The addition of CEM to separator with the cathode and anode could significantly improve current efficiency. The cathode materials had significant effect on the reduction of acrylate. The current efficiency by Pd/Nickel foam, was greater than 90%, while those by nickel foam, the carbon fibers and the stainless steel decreased successively. Toxicity of the wastewater decreased considerably and methane production rate in the biochemical methane potential (BMP) test increased greatly after the electrocatalytic reduction process.

  19. In vitro release of clomipramine HCl and buprenorphine HCl from poly adipic anhydride (PAA) and poly trimethylene carbonate (PTMC) blends.

    PubMed

    Dinarvand, Rassoul; Alimorad, Mohammed Massoud; Amanlou, Massoud; Akbari, Hamid

    2005-10-01

    Controlled drug-delivery technology is concerned with the systematic release of a pharmaceutical agent to maintain a therapeutic level of the drug in the body for modulated and/or prolonged periods of time. This may be achieved by incorporating the therapeutic agent into a degradable polymer vehicle, which releases the agent continuously as the matrix erodes. In this study, poly trimethylene carbonate (PTMC), an aliphatic polycarbonate, and poly adipic anhydride (PAA), an aliphatic polyanhydride, were synthesized via melt condensation and ring-opening polymerization of trimethylene carbonate and adipic acid, respectively. The release of clomipramine HCl and buprenorphine HCl from discs prepared with the use of PTMC-PAA blends in phosphate buffer (pH 7.4) are also described. Clomipramine HCl and buprenorphine HCl were both used as hydrophilic drug models. Theoretical treatment of the data with the Peppas model revealed that release of clomipramine HCl (5%) in devices containing 70% PTMC or more followed a Fickian diffusion model. However, the releases of buprenorphine HCl (5%) in the same devices were anomalous. For devices containing 50% and more PAA, surface erosion may play a significant role in the release of both molecules.

  20. Micelle-assisted signaling of peracetic acid by the oxidation of pyreneboronic acid via monomer-excimer switching.

    PubMed

    Choi, Jiyoung; Lee, Hyo Jin; Cho, Min Jeoung; Chang, Suk-Kyu

    2015-08-15

    A simple fluorescent probe for the industrial oxidant peracetic acid (PAA) was investigated. PAA-assisted oxidative conversion of pyrene-1-boronic acid into 1-hydroxypyrene was used as the signaling tool. Pyreneboronic acid was found to display selective signaling behavior, being more responsive to PAA than to other commonly used practical oxidants such as H2O2 and HOCl. The changes in pyrene monomer fluorescence to excimer were used in the quantitative analysis of PAA. When using the surfactant hexadecyltrimethylammonium bromide as a micellar additive, the signaling of PAA was markedly enhanced. Selective fluorescence signaling of PAA by pyrene-1-boronic acid with a detection limit of 1.5×10(-6)M in aqueous environment was successfully achieved. PMID:25966389

  1. Preparation and properties of UV curable acrylic PSA by vinyl bonded graphene oxide

    NASA Astrophysics Data System (ADS)

    Pang, Beili; Ryu, Chong-Min; Jin, Xin; Kim, Hyung-Il

    2013-11-01

    Acrylic pressure sensitive adhesives (PSAs) with higher thermal stability for thin wafer handling were successfully prepared by forming composite with the graphene oxide (GO) nanoparticles modified to have vinyl groups via subsequent reaction with isophorone diisocyanate and 2-hydroxyethyl methacrylate. The acrylic copolymer was synthesized as a base resin for PSAs by solution radical polymerization of ethyl acrylate, 2-ethylhexyl acrylate, and acrylic acid followed by further modification with GMA to have the vinyl groups available for UV curing. The peel strength of PSA decreased with the increase of gel content which was dependent on both modified GO content and UV dose. Thermal stability of UV-cured PSA was improved noticeably with increasing the modified GO content mainly due to the strong and extensive interfacial bonding formed between the acrylic copolymer matrix and GO fillers

  2. Epoxy-acrylic core-shell particles by seeded emulsion polymerization.

    PubMed

    Chen, Liang; Hong, Liang; Lin, Jui-Ching; Meyers, Greg; Harris, Joseph; Radler, Michael

    2016-07-01

    We developed a novel method for synthesizing epoxy-acrylic hybrid latexes. We first prepared an aqueous dispersion of high molecular weight solid epoxy prepolymers using a mechanical dispersion process at elevated temperatures, and we subsequently used the epoxy dispersion as a seed in the emulsion polymerization of acrylic monomers comprising methyl methacrylate (MMA) and methacrylic acid (MAA). Advanced analytical techniques, such as scanning transmission X-ray microscopy (STXM) and peak force tapping atomic force microscopy (PFT-AFM), have elucidated a unique core-shell morphology of the epoxy-acrylic hybrid particles. Moreover, the formation of the core-shell morphology in the seeded emulsion polymerization process is primarily attributed to kinetic trapping of the acrylic phase at the exterior of the epoxy particles. By this new method, we are able to design the epoxy and acrylic polymers in two separate steps, and we can potentially synthesize epoxy-acrylic hybrid latexes with a broad range of compositions. PMID:27078740

  3. Epoxy-acrylic core-shell particles by seeded emulsion polymerization.

    PubMed

    Chen, Liang; Hong, Liang; Lin, Jui-Ching; Meyers, Greg; Harris, Joseph; Radler, Michael

    2016-07-01

    We developed a novel method for synthesizing epoxy-acrylic hybrid latexes. We first prepared an aqueous dispersion of high molecular weight solid epoxy prepolymers using a mechanical dispersion process at elevated temperatures, and we subsequently used the epoxy dispersion as a seed in the emulsion polymerization of acrylic monomers comprising methyl methacrylate (MMA) and methacrylic acid (MAA). Advanced analytical techniques, such as scanning transmission X-ray microscopy (STXM) and peak force tapping atomic force microscopy (PFT-AFM), have elucidated a unique core-shell morphology of the epoxy-acrylic hybrid particles. Moreover, the formation of the core-shell morphology in the seeded emulsion polymerization process is primarily attributed to kinetic trapping of the acrylic phase at the exterior of the epoxy particles. By this new method, we are able to design the epoxy and acrylic polymers in two separate steps, and we can potentially synthesize epoxy-acrylic hybrid latexes with a broad range of compositions.

  4. Advances in acrylic-alkyd hybrid synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Dziczkowski, Jamie

    2008-10-01

    In situ graft acrylic-alkyd hybrid resins were formed by polymerizing acrylic and acrylic-mixed monomers in the presence of alkyds by introduction of a free radical initiator to promote graft formation. Two-dimensional NMR, specifically gradient heteronuclear multiple quantum coherence (gHMQC), was used to clarify specific graft sites of the hybrid materials. Both individual and mixed-monomer systems were produced to determine any individual monomer preferences and to model current acrylic-alkyd systems. Different classes of initiators were used to determine any initiator effects on graft location. The 2D-NMR results confirm grafting at doubly allylic hydrogens located on the fatty acid chains and the polyol segment of the alkyd backbone. The gHMQC spectra show no evidence of grafting across double bonds on either pendant fatty acid groups or THPA unsaturation sites for any of the monomer or mixed monomer systems. It was also determined that choice of initiator has no effect on graft location. In addition, a design of experiments using response surface methodology was utilized to obtain a better understanding of this commercially available class of materials and relate both the chemical and physical properties to one another. A Box-Behnkin design was used, varying the oil length of the alkyd phase, the degree of unsaturation in the polyester backbone, and acrylic to alkyd ratio. Acrylic-alkyd hybrid resins were reduced with an amine/water mixture. Hydrolytic stability was tested and viscoelastic properties were obtained to determine crosslink density. Cured films were prepared and basic coatings properties were evaluated. It was found that the oil length of the alkyd is the most dominant factor for final coatings properties of the resins. Acrylic to alkyd ratio mainly influences the resin properties such as acid number, average molecular weight, and hydrolytic stability. The degree of unsaturation in the alkyd backbone has minimal effects on resin and film

  5. The acute aquatic toxicity of a series of acrylate and methacrylate esters

    SciTech Connect

    Staples, C.A.; McLaughlin, J.E.; Hamilton, J.D.

    1994-12-31

    Acute aquatic toxicity data for several acrylate and methacrylate esters were reviewed. Acrylates included acrylic acid, ethyl-, and butyl-acrylate. Methacrylates included methacrylic acid, methyl-, and butyl-methacrylate. Tests were 48 hr or 96 hr standard flow through (invertebrates and fish) assays (measured exposure concentrations). These data are currently used in a risk assessment of acrylate/methacrylate environmental safety. Algal growth (Selanastrum capricomutum) 96 hr EC{sub 50}s were 0.17 mg/L (NOEC < 0.13 mg/L) for acrylic acid, 11.0 mg/L (NOEC < 6.5 mg/L) for ethyl acrylate, and 5.2 mg/L (NOEC < 3.8 mg/L) for butyl acrylate. Invertebrate (Daphnia magna) 48 hr LC{sub 50}s were 95.0 mg/L (NOEC 23.0 mg/L) for acrylic acid, 7.9 mg/L (NOEC 3.4 mg/L) for ethyl acrylate, and 8.2 mg/L (NOEC 2.4 mg/L) for butyl acrylate. Rainbow trout (Oncorhynchus mykiss) 96 hr LC{sub 50}s were 27.0 mg/L (NOEC 6.3 mg/L) for acrylic acid, 4.6 mg/L (NOEC 0.78 mg/L) for ethyl acrylate, and 5.2 mg/L (NOEC 3.8 mg/L) for butyl acrylate. Algae 96 hr EC{sub 50}s were 0.59 mg/L (NOEC 0.38 mg/L) for methacrylic acid, 170.0 mg/L (NOEC 100.0 mg/L) for methyl methacrylate, and 130.0 mg/L for butyl methacrylate. Daphnia magna 48 hr LC{sub 50}s were > 130.0 mg/L (NOEC 130.0 mg/L) for methacrylic acid, 69.0 mg/L (NOEC 48.0 mg/L) for methyl methacrylate, and 32.0 mg/L (NOEC 23.0 mg/L) for butyl methacrylate. Trout 96 hr LC{sub 50}s were 85.0 mg/L (NOEC 12.0 mg/L) for methacrylic acid and > 79.0 mg/L (NOEC 40.0 mg/L) for methyl methacrylate. The fathead minnow (Pimephales promelas) 96 hr LC{sub 50} was 11.0 mg/L for butyl methacrylate.

  6. [Acrylic resin removable partial dentures].

    PubMed

    de Baat, C; Witter, D J; Creugers, N H J

    2011-01-01

    An acrylic resin removable partial denture is distinguished from other types of removable partial dentures by an all-acrylic resin base which is, in principle, solely supported by the edentulous regions of the tooth arch and in the maxilla also by the hard palate. When compared to the other types of removable partial dentures, the acrylic resin removable partial denture has 3 favourable aspects: the economic aspect, its aesthetic quality and the ease with which it can be extended and adjusted. Disadvantages are an increased risk of caries developing, gingivitis, periodontal disease, denture stomatitis, alveolar bone reduction, tooth migration, triggering of the gag reflex and damage to the acrylic resin base. Present-day indications are ofa temporary or palliative nature or are motivated by economic factors. Special varieties of the acrylic resin removable partial denture are the spoon denture, the flexible denture fabricated of non-rigid acrylic resin, and the two-piece sectional denture. Furthermore, acrylic resin removable partial dentures can be supplied with clasps or reinforced by fibers or metal wires.

  7. Using NMR chemical shift imaging to monitor swelling and molecular transport in drug-loaded tablets of hydrophobically modified poly(acrylic acid): methodology and effects of polymer (in)solubility.

    PubMed

    Knöös, Patrik; Topgaard, Daniel; Wahlgren, Marie; Ulvenlund, Stefan; Piculell, Lennart

    2013-11-12

    A new technique has been developed using NMR chemical shift imaging (CSI) to monitor water penetration and molecular transport in initially dry polymer tablets that also contain small low-molecular weight compounds to be released from the tablets. Concentration profiles of components contained in the swelling tablets could be extracted via the intensities and chemical shift changes of peaks corresponding to protons of the components. The studied tablets contained hydrophobically modified poly(acrylic acid) (HMPAA) as the polymer component and griseofulvin and ethanol as hydrophobic and hydrophilic, respectively, low-molecular weight model compounds. The water solubility of HMPAA could be altered by titration with NaOH. In the pure acid form, HMPAA tablets only underwent a finite swelling until the maximum water content of the polymer-rich phase, as confirmed by independent phase studies, had been reached. By contrast, after partial neutralization with NaOH, the polyacid became fully miscible with water. The solubility of the polymer affected the water penetration, the polymer release, and the releases of both ethanol and griseofulvin. The detailed NMR CSI concentration profiles obtained highlighted the clear differences in the disintegration/dissolution/release behavior for the two types of tablet and provided insights into their molecular origin. The study illustrates the potential of the NMR CSI technique to give information of importance for the development of pharmaceutical tablets and, more broadly, for the general understanding of any operation that involves the immersion and ultimate disintegration of a dry polymer matrix in a solvent.

  8. Synthesis, characterization, and morphology study of poly(acrylamide-co-acrylic acid)-grafted-poly(styrene-co-methyl methacrylate) "raspberry"-shape like structure microgels by pre-emulsified semi-batch emulsion polymerization.

    PubMed

    Ramli, Ros Azlinawati; Hashim, Shahrir; Laftah, Waham Ashaier

    2013-02-01

    A novel microgels were polymerized using styrene (St), methyl methacrylate (MMA), acrylamide (AAm), and acrylic acid (AAc) monomers in the presence of N,N'-methylenebisacrylamide (MBA) cross-linker. Pre-emulsified monomer was first prepared followed by polymerizing monomers using semi-batch emulsion polymerization. Fourier Transform Infrared Spectroscopy (FTIR) and (1)H Nuclear Magnetic Resonance (NMR) were used to determine the chemical structure and to indentify the related functional group. Grafting and cross-linking of poly(acrylamide-co-acrilic acid)-grafted-poly(styrene-co-methyl methacrylate) [poly(AAm-co-AAc)-g-poly(St-co-MMA)] microgels are approved by the disappearance of band at 1300 cm(-1), 1200 cm(-1) and 1163 cm(-1) of FTIR spectrum and the appearance of CH peaks at 5.5-5.7 ppm in (1)H NMR spectrum. Scanning Electron Microscope (SEM) images indicated that poly(St-co-MMA) particle was lobed morphology coated by cross-linked poly(AAm-co-AAc) shell. Furthermore, SEM results revealed that poly(AAm-co-AAc)-g-poly(St-co-MMA) is composite particle that consist of "raspberry"-shape like structure core. Internal structures of the microgels showed homogeneous network of pores, an extensive interconnection among pores, thicker pore walls, and open network structures. Water absorbency test indicated that the sample with particle size 0.43 μm had lower equilibrium water content, % than the sample with particle size 7.39 μm. PMID:23123033

  9. Distinct Characteristics of Indole-3-Acetic Acid and Phenylacetic Acid, Two Common Auxins in Plants.

    PubMed

    Sugawara, Satoko; Mashiguchi, Kiyoshi; Tanaka, Keita; Hishiyama, Shojiro; Sakai, Tatsuya; Hanada, Kousuke; Kinoshita-Tsujimura, Kaori; Yu, Hong; Dai, Xinhua; Takebayashi, Yumiko; Takeda-Kamiya, Noriko; Kakimoto, Tatsuo; Kawaide, Hiroshi; Natsume, Masahiro; Estelle, Mark; Zhao, Yunde; Hayashi, Ken-Ichiro; Kamiya, Yuji; Kasahara, Hiroyuki

    2015-08-01

    The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin for >40 years, but its role in plant growth and development remains unclear. In this study, we show that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB pathway in Arabidopsis. IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. The induction of the YUCCA (YUC) genes increases PAA metabolite levels in Arabidopsis, indicating that YUC flavin-containing monooxygenases may play a role in PAA biosynthesis. Our results provide new insights into the regulation of plant growth and development by different types of auxins. PMID:26076971

  10. Distinct Characteristics of Indole-3-Acetic Acid and Phenylacetic Acid, Two Common Auxins in Plants

    PubMed Central

    Sugawara, Satoko; Mashiguchi, Kiyoshi; Tanaka, Keita; Hishiyama, Shojiro; Sakai, Tatsuya; Hanada, Kousuke; Kinoshita-Tsujimura, Kaori; Yu, Hong; Dai, Xinhua; Takebayashi, Yumiko; Takeda-Kamiya, Noriko; Kakimoto, Tatsuo; Kawaide, Hiroshi; Natsume, Masahiro; Estelle, Mark; Zhao, Yunde; Hayashi, Ken-ichiro; Kamiya, Yuji; Kasahara, Hiroyuki

    2015-01-01

    The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin for >40 years, but its role in plant growth and development remains unclear. In this study, we show that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB pathway in Arabidopsis. IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. The induction of the YUCCA (YUC) genes increases PAA metabolite levels in Arabidopsis, indicating that YUC flavin-containing monooxygenases may play a role in PAA biosynthesis. Our results provide new insights into the regulation of plant growth and development by different types of auxins. PMID:26076971

  11. Distinct Characteristics of Indole-3-Acetic Acid and Phenylacetic Acid, Two Common Auxins in Plants.

    PubMed

    Sugawara, Satoko; Mashiguchi, Kiyoshi; Tanaka, Keita; Hishiyama, Shojiro; Sakai, Tatsuya; Hanada, Kousuke; Kinoshita-Tsujimura, Kaori; Yu, Hong; Dai, Xinhua; Takebayashi, Yumiko; Takeda-Kamiya, Noriko; Kakimoto, Tatsuo; Kawaide, Hiroshi; Natsume, Masahiro; Estelle, Mark; Zhao, Yunde; Hayashi, Ken-Ichiro; Kamiya, Yuji; Kasahara, Hiroyuki

    2015-08-01

    The phytohormone auxin plays a central role in many aspects of plant growth and development. IAA is the most studied natural auxin that possesses the property of polar transport in plants. Phenylacetic acid (PAA) has also been recognized as a natural auxin for >40 years, but its role in plant growth and development remains unclear. In this study, we show that IAA and PAA have overlapping regulatory roles but distinct transport characteristics as auxins in plants. PAA is widely distributed in vascular and non-vascular plants. Although the biological activities of PAA are lower than those of IAA, the endogenous levels of PAA are much higher than those of IAA in various plant tissues in Arabidopsis. PAA and IAA can regulate the same set of auxin-responsive genes through the TIR1/AFB pathway in Arabidopsis. IAA actively forms concentration gradients in maize coleoptiles in response to gravitropic stimulation, whereas PAA does not, indicating that PAA is not actively transported in a polar manner. The induction of the YUCCA (YUC) genes increases PAA metabolite levels in Arabidopsis, indicating that YUC flavin-containing monooxygenases may play a role in PAA biosynthesis. Our results provide new insights into the regulation of plant growth and development by different types of auxins.

  12. Synthesis of Radiation Curable Palm Oil-Based Epoxy Acrylate: NMR and FTIR Spectroscopic Investigations.

    PubMed

    Salih, Ashraf M; Ahmad, Mansor Bin; Ibrahim, Nor Azowa; Dahlan, Khairul Zaman Hj Mohd; Tajau, Rida; Mahmood, Mohd Hilmi; Yunus, Wan Md Zin Wan

    2015-01-01

    Over the past few decades, there has been an increasing demand for bio-based polymers and resins in industrial applications, due to their potential lower cost and environmental impact compared with petroleum-based counterparts. The present research concerns the synthesis of epoxidized palm oil acrylate (EPOLA) from an epoxidized palm oil product (EPOP) as environmentally friendly material. EPOP was acrylated by acrylic acid via a ring opening reaction. The kinetics of the acrylation reaction were monitored throughout the reaction course and the acid value of the reaction mixture reached 10 mg KOH/g after 16 h, indicating the consumption of the acrylic acid. The obtained epoxy acrylate was investigated intensively by means of FTIR and NMR spectroscopy, and the results revealed that the ring opening reaction was completed successfully with an acrylation yield about 82%. The UV free radical polymerization of EPOLA was carried out using two types of photoinitiators. The radiation curing behavior was determined by following the conversion of the acrylate groups. The cross-linking density and the hardness of the cured EPOLA films were measured to evaluate the effect of the photoinitiator on the solid film characteristics, besides, the thermal and mechanical properties were also evaluated. PMID:26248072

  13. Study of Molecular Conformation and Activity-Related Properties of Lipase Immobilized onto Core-Shell Structured Polyacrylic Acid-Coated Magnetic Silica Nanocomposite Particles.

    PubMed

    Esmaeilnejad-Ahranjani, Parvaneh; Kazemeini, Mohammad; Singh, Gurvinder; Arpanaei, Ayyoob

    2016-04-01

    A facile approach for the preparation of core-shell structured poly(acrylic acid) (PAA)-coated Fe3O4 cluster@SiO2 nanocomposite particles as the support materials for the lipase immobilization is reported. Low- or high-molecular-weight (1800 and 100,000, respectively) PAA molecules were covalently attached onto the surface of amine-functionalized magnetic silica nanoacomposite particles. The successful preparation of particles were verified by scanning transmission electron microscopy (STEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), zeta potential measurement, and Fourier-transform infrared (FTIR) techniques. Once lipase is covalently immobilized onto the particles with an average diameter of 210 ± 50 nm, resulting from high binding sites concentrations on the low- and high-molecular-weight PAA-coated particles, high lipase immobilization efficiencies (86.2% and 89.9%, respectively), and loading capacities (786 and 816 mg g(-1), respectively) are obtained. Results from circular dichroism (CD) analysis and catalytic activity tests reveal an increase in the β-sheet content of lipase molecules upon immobilization, along with an enhancement in their activities and stabilities. The lipases immobilized onto the low- and high-molecular-weight PAA-coated particles show maximum activities at 55 and 50 °C, respectively, which are ∼28% and ∼15% higher than that of the free lipase at its own optimum temperature (40 °C), respectively. The immobilized lipases exhibit excellent performance at broader temperature and pH ranges and high thermal and storage stabilities, as well as superior reusability. These prepared magnetic nanocomposite particles can be offered as suitable support materials for efficient immobilization of enzymes and improvement of the immobilized enzymes properties.

  14. Degradation of a Sodium Acrylate Oligomer by an Arthrobacter sp

    PubMed Central

    Hayashi, Takaya; Mukouyama, Masaharu; Sakano, Kouichi; Tani, Yoshiki

    1993-01-01

    Arthrobacter sp. strain NO-18 was first isolated from soil as a bacterium which could degrade the sodium acrylate oligomer and utilize it as the sole source of carbon. When 0.2% (wt/wt) oligomer was added to the culture medium, the acrylate oligomer was found to be degraded by 70 to 80% in 2 weeks, using gel permeation chromatography. To determine the maximum molecular weight for biodegradation, the degradation test was done with the hexamer, heptamer, and octamer, which were separated from the oligomer mixture by fractional gel permeation chromatography. The hexamer and heptamer were consumed to the extents of 58 and 36%, respectively, in 2 weeks, but the octamer was not degraded. Oligomers with three different terminal groups were synthesized to examine the effect of the different terminal groups on biodegradation, but few differences were found. Arthrobacter sp. NO-18 assimilated acrylic acid, propionic acid, glutaric acid, 2-methylglutaric acid, and 1,3,5-pentanetricarboxylic acid. Degradation of the acrylic unit structure by this strain is discussed. PMID:8517751

  15. Acid-catalytic decomposition of peracetic acid in the liquid phase

    SciTech Connect

    Kharchuk, V.G.; Kolenko, I.P.; Petrov, L.A.

    1985-12-01

    This paper elucidates the kinetic relationships of peracetic acid (PAA) decomposition in the presence of mineral acids and their heterogeneous analogs, polystyrene-di-vinylbenzene cation-exchangers, differing in physicochemical and morphological parameters. It is shown that the thermal decomposition of PAA in acetic acid is an acid-catalyzed reaction. The controlling step of the reaction is protonation of the substrate with formation of an active intermediate form. Sulfonated cation-exchangers are twice as effective as sulfuric acid in this process. Polystyrene-divinylbenzene sulfonated cation-exchangers can be used with success as acid catalysts in oxidation processes involving PAA, because of their high effectiveness, stability, and availability.

  16. Auxin Biosynthesis: Are the Indole-3-Acetic Acid and Phenylacetic Acid Biosynthesis Pathways Mirror Images?

    PubMed

    Cook, Sam D; Nichols, David S; Smith, Jason; Chourey, Prem S; McAdam, Erin L; Quittenden, Laura; Ross, John J

    2016-06-01

    The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway. PMID:27208245

  17. Peracetic acid oxidation of saline waters in the absence and presence of H ₂O ₂: secondary oxidant and disinfection byproduct formation.

    PubMed

    Shah, Amisha D; Liu, Zheng-Qian; Salhi, Elisabeth; Höfer, Thomas; von Gunten, Urs

    2015-02-01

    Peracetic acid (PAA) is a disinfectant considered for use in ballast water treatment, but its chemical behavior in such systems (i.e., saline waters) is largely unknown. In this study, the reactivity of PAA with halide ions (chloride and bromide) to form secondary oxidants (HOCl, HOBr) was investigated. For the PAA-chloride and PAA-bromide reactions, second-order rate constants of (1.47 ± 0.58) × 10(-5) and 0.24 ± 0.02 M(-1) s(-1) were determined for the formation of HOCl or HOBr, respectively. Hydrogen peroxide (H2O2), which is always present in PAA solutions, reduced HOCl or HOBr to chloride or bromide, respectively. As a consequence, in PAA-treated solutions with [H2O2] > [PAA], the HOBr (HOCl) steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs). HOI (formed from the PAA-iodide reaction) affected this process because it can react with H2O2 back to iodide. H2O2 is thus consumed in a catalytic cycle and leads to less efficient HOBr scavenging at even low iodide concentrations (<1 μM). In PAA-treated solutions with [H2O2] < [PAA] and high bromide levels, mostly brominated DBPs are formed. In synthetic water, bromate was formed from the oxidation of bromide. In natural brackish waters, bromoform (CHBr3), bromoacetic acid (MBAA), dibromoacetic acid (DBAA), and tribromoacetic acid (TBAA) formed at up to 260, 106, 230, and 89 μg/L, respectively for doses of 2 mM (ca. 150 mg/L) PAA and [H2O2] < [PAA]. The same brackish waters, treated with PAA with [H2O2] ≫ [PAA], similar to conditions found in commercial PAA solutions, resulted in no trihalomethanes and only low haloacetic acid concentrations.

  18. Peracetic acid oxidation of saline waters in the absence and presence of H ₂O ₂: secondary oxidant and disinfection byproduct formation.

    PubMed

    Shah, Amisha D; Liu, Zheng-Qian; Salhi, Elisabeth; Höfer, Thomas; von Gunten, Urs

    2015-02-01

    Peracetic acid (PAA) is a disinfectant considered for use in ballast water treatment, but its chemical behavior in such systems (i.e., saline waters) is largely unknown. In this study, the reactivity of PAA with halide ions (chloride and bromide) to form secondary oxidants (HOCl, HOBr) was investigated. For the PAA-chloride and PAA-bromide reactions, second-order rate constants of (1.47 ± 0.58) × 10(-5) and 0.24 ± 0.02 M(-1) s(-1) were determined for the formation of HOCl or HOBr, respectively. Hydrogen peroxide (H2O2), which is always present in PAA solutions, reduced HOCl or HOBr to chloride or bromide, respectively. As a consequence, in PAA-treated solutions with [H2O2] > [PAA], the HOBr (HOCl) steady-state concentrations were low with a limited formation of brominated (chlorinated) disinfection byproducts (DBPs). HOI (formed from the PAA-iodide reaction) affected this process because it can react with H2O2 back to iodide. H2O2 is thus consumed in a catalytic cycle and leads to less efficient HOBr scavenging at even low iodide concentrations (<1 μM). In PAA-treated solutions with [H2O2] < [PAA] and high bromide levels, mostly brominated DBPs are formed. In synthetic water, bromate was formed from the oxidation of bromide. In natural brackish waters, bromoform (CHBr3), bromoacetic acid (MBAA), dibromoacetic acid (DBAA), and tribromoacetic acid (TBAA) formed at up to 260, 106, 230, and 89 μg/L, respectively for doses of 2 mM (ca. 150 mg/L) PAA and [H2O2] < [PAA]. The same brackish waters, treated with PAA with [H2O2] ≫ [PAA], similar to conditions found in commercial PAA solutions, resulted in no trihalomethanes and only low haloacetic acid concentrations. PMID:25611970

  19. Kinetic relationships governing addition of methanol to methyl acrylate

    SciTech Connect

    Chubarov, G.A.; Danov, S.M.; Kutnyaya, M.Yu.

    1988-11-10

    The kinetic relationships governing the addition of methanol to methyl acrylate and the reverse reaction, i.e., the elimination of methanol from methyl /beta/-methoxypropionate catalyzed by sulfuric and p-toluenesulfonic acids, were investigated. The rate of the forward reaction depends on the concentrations of methyl acrylate, methanol, and the catalyst, and the rate of the reverse reaction depends on the concentration of methyl /beta/-methoxypropionate and of the catalyst. A kinetic expression which describes the process well was obtained.

  20. Corrosion resistant properties of polyaniline acrylic coating on magnesium alloy

    NASA Astrophysics Data System (ADS)

    Sathiyanarayanan, S.; Azim, S. Syed; Venkatachari, G.

    2006-12-01

    The performance of the paint coating based on acrylic-polyaniline on magnesium alloy ZM 21 has been studied by electrochemical impedance spectroscopy in 0.5% NaCl solution. The polyaniline was prepared by chemical oxidative method of aniline with ammonium persulphate in phosphoric acid medium. The phosphate-doped polyaniline was characterized by FTIR and XRD methods. Acrylic paint containing the phosphate-doped polyaniline was prepared and coated on magnesium ZM 21 alloy. The coating was able to protect the magnesium alloy and no base metal dissolution was noted even after 75 days exposure to sodium chloride solution.

  1. Selective electrochemical detection of 2,4,6-trinitrotoluene (TNT) in water based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin-modified glassy carbon electrode.

    PubMed

    Mahmoud, Khaled A; Abdel-Wahab, Ahmed; Zourob, Mohammed

    2015-01-01

    A new versatile electrochemical sensor based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin (L-MMS) modified glassy carbon electrode (GCE) was developed for the selective detection of trace trinitrotoluene (TNT) from aqueous media with high sensitivity. The fabricated magnetic microspheres were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). L-MMS films were cast on the GCE surface to fabricate the TNT sensing electrode. The limit of detection (LOD) of TNT determined by the amperometric i-t curve reached 35 pM. The lignin film and well packed Fe3O4/AuNPs facilitated the pre-concentration of trace TNT on the electrode surface resulting in a fast amperometric response of 3 seconds near the detection limit. The high sensitivity and excellent catalytic activity of the modified electrode could be attributed to the lignin layer and highly packed Fe3O4/AuNPs on the electrode surface. The total recovery of TNT from tapwater and seawater matrices was 98% and 96%, respectively. The electrode film was highly stable after five repeated adsorption/desorption cycles. The new electrochemical sensing scheme provides a highly selective, sensitive and versatile assay for the in-situ detection of TNT in complex water media.

  2. Selective electrochemical detection of 2,4,6-trinitrotoluene (TNT) in water based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin-modified glassy carbon electrode.

    PubMed

    Mahmoud, Khaled A; Abdel-Wahab, Ahmed; Zourob, Mohammed

    2015-01-01

    A new versatile electrochemical sensor based on poly(styrene-co-acrylic acid) PSA/SiO2/Fe3O4/AuNPs/lignin (L-MMS) modified glassy carbon electrode (GCE) was developed for the selective detection of trace trinitrotoluene (TNT) from aqueous media with high sensitivity. The fabricated magnetic microspheres were characterized by transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). L-MMS films were cast on the GCE surface to fabricate the TNT sensing electrode. The limit of detection (LOD) of TNT determined by the amperometric i-t curve reached 35 pM. The lignin film and well packed Fe3O4/AuNPs facilitated the pre-concentration of trace TNT on the electrode surface resulting in a fast amperometric response of 3 seconds near the detection limit. The high sensitivity and excellent catalytic activity of the modified electrode could be attributed to the lignin layer and highly packed Fe3O4/AuNPs on the electrode surface. The total recovery of TNT from tapwater and seawater matrices was 98% and 96%, respectively. The electrode film was highly stable after five repeated adsorption/desorption cycles. The new electrochemical sensing scheme provides a highly selective, sensitive and versatile assay for the in-situ detection of TNT in complex water media. PMID:26540539

  3. Investigation of Changes in the Microscopic Structure of Anionic Poly(N-isopropylacrylamide-co-Acrylic acid) Microgels in the Presence of Cationic Organic Dyes toward Precisely Controlled Uptake/Release of Low-Molecular-Weight Chemical Compound.

    PubMed

    Kureha, Takuma; Shibamoto, Takahisa; Matsui, Shusuke; Sato, Takaaki; Suzuki, Daisuke

    2016-05-10

    Changes in a microscopic structure of an anionic poly(N-isopropylacrylamide-co-acrylic acid) microgel were investigated using small- and wide-angle X-ray scattering (SWAXS). The scattering profiles of the microgels were analyzed in a wide scattering vector (q) range of 0.07 ≤ q/nm(-1) ≤ 20. In particular, the microscopic structure of the microgel in the presence of a cationic dye rhodamine 6G (R6G) was characterized in terms of its correlation length (ξ), which represents the length scale of the spatial correlation of the network density fluctuations, and characteristic distance (d*), which originated from the local packing of isopropyl groups of two neighboring chains. In the presence of cationic R6G, ξ exhibited a divergent-like behavior, which was not seen in the absence of R6G, and d* was decreased with decreasing the volume of the microgel upon increasing temperature. At the same time, the amount of R6G adsorbed per unit mass of the microgel increased upon heating. These results suggested that a coil-to-globule transition of the poly(N-isopropylacrylamide) chains in the present anionic microgel occurred because of efficiently screened, thus, short ranged electrostatic repulsion between the charged groups, and hydrophobic interaction between the isopropyl groups in the presence of cationic R6G. The combination of hydrophobic and electrostatic interaction between the cationic dye and the microgel affected the separation and volume transition behavior of the microgel. PMID:27101468

  4. Azospirillum brasilense Produces the Auxin-Like Phenylacetic Acid by Using the Key Enzyme for Indole-3-Acetic Acid Biosynthesis

    PubMed Central

    Somers, E.; Ptacek, D.; Gysegom, P.; Srinivasan, M.; Vanderleyden, J.

    2005-01-01

    An antimicrobial compound was isolated from Azospirillum brasilense culture extracts by high-performance liquid chromatography and further identified by gas chromatography-mass spectrometry as the auxin-like molecule, phenylacetic acid (PAA). PAA synthesis was found to be mediated by the indole-3-pyruvate decarboxylase, previously identified as a key enzyme in indole-3-acetic acid (IAA) production in A. brasilense. In minimal growth medium, PAA biosynthesis by A. brasilense was only observed in the presence of phenylalanine (or precursors thereof). This observation suggests deamination of phenylalanine, decarboxylation of phenylpyruvate, and subsequent oxidation of phenylacetaldehyde as the most likely pathway for PAA synthesis. Expression analysis revealed that transcription of the ipdC gene is upregulated by PAA, as was previously described for IAA and synthetic auxins, indicating a positive feedback regulation. The synthesis of PAA by A. brasilense is discussed in relation to previously reported biocontrol properties of A. brasilense. PMID:15812004

  5. Biocatalytic functionalization of hydroxyalkyl acrylates and phenoxyethanol via phosphorylation.

    PubMed

    Tasnádi, Gábor; Hall, Mélanie; Baldenius, Kai; Ditrich, Klaus; Faber, Kurt

    2016-09-10

    The enzymatic phosphorylation of phenoxyethanol, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate catalyzed by acid phosphatases PhoN-Sf and PiACP at the expense of inorganic di-, tri-, hexameta- or polyphosphate was applied to the preparative-scale synthesis of phosphorylated compounds. The reaction conditions were optimized with respect to enzyme immobilization, substrate concentration, pH and type of phosphate donor. The mild reaction conditions prevented undesired polymerization and hydrolysis of the acrylate ester moiety. Application of a continuous flow system allowed facile scale-up and mono-phosphates were obtained in up to 26% isolated yield with space-time yields of 0.89kgL(-1)h(-1). PMID:27422352

  6. Biocatalytic functionalization of hydroxyalkyl acrylates and phenoxyethanol via phosphorylation.

    PubMed

    Tasnádi, Gábor; Hall, Mélanie; Baldenius, Kai; Ditrich, Klaus; Faber, Kurt

    2016-09-10

    The enzymatic phosphorylation of phenoxyethanol, 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate catalyzed by acid phosphatases PhoN-Sf and PiACP at the expense of inorganic di-, tri-, hexameta- or polyphosphate was applied to the preparative-scale synthesis of phosphorylated compounds. The reaction conditions were optimized with respect to enzyme immobilization, substrate concentration, pH and type of phosphate donor. The mild reaction conditions prevented undesired polymerization and hydrolysis of the acrylate ester moiety. Application of a continuous flow system allowed facile scale-up and mono-phosphates were obtained in up to 26% isolated yield with space-time yields of 0.89kgL(-1)h(-1).

  7. Bonding auto-polymerising acrylic resin to acrylic denture teeth.

    PubMed

    Nagle, Susan; Ray, Noel J; Burke, Francis M; Gorman, Catherine M

    2009-09-01

    This study investigated the effect of surface treatments on the shear bond strength of an auto-polymerising acrylic resin cured to acrylic denture teeth. The surface treatments included a combination of grit-blasting and/or wetting the surface with monomer. Samples were prepared and then stored in water prior to shear testing. The results indicated that the application of monomer to the surface prior to bonding did not influence the bond strength. Grit blasting was found to significantly increase the bond strength. PMID:19839190

  8. Synthesis and characterization of acrylic type hydrogels containing azo derivatives of 5-amino salicylic acid for colon-specific drug delivery.

    PubMed

    Mahkam, M; Doostie, L; Siadat, S O R

    2006-03-01

    pH-sensitive hydrogels are suitable candidates for oral delivery of therapeutic peptides, proteins and drugs, due to their ability to respond to environmental pH changes. Terephthalic acid was covalently linked with 2-hydroxyethyl methacrylate (HEMA), abbreviated as cross-linking agent (CA). Acryloyl ester of 5-[4-(hydroxy phenyl) azo] salicylic acid (HPAS) as an azo derivative of 5-amino salicylic acid (5-ASA) was prepared under mild conditions. The HPAS was covalently linked with acryloyl chloride, abbreviated as APAS. Free radical cross-linking copolymerization of polymerizable azo derivative of 5-ASA (APAS) and methacrylic acid (MAA) in two different molar ratios, with the various ratios CA as cross-linking agent were carried out with using 2, 2'-azobisisobutyronitrile (AIBN) as initiator at the temperature range 60-70 degrees C. The composition of the cross-linked three-dimensional polymers was determined by FTIR spectroscopy. Glass transition temperature (Tg) of the network polymers was determined calorimetrically. The hydrolysis of drug-polymer conjugates was carried out in cellophane membrane dialysis bags containing aqueous buffer solutions (pH 7.4 and pH 1) at 37 degrees C. The effect of copolymer composition on the hydrolytic degradation was studied in simulated gastric fluid (SGF, pH 1) and simulated intestinal fluid (SIF, pH 7.4) at 37 degrees C. Monitoring of the hydrolysis process by HPLC and UV spectroscopy shows that the azo prodrug (HPAS) was released by hydrolysis of the ester bond located between the HPAS and the polymer chain. The drug-release profiles indicate that amount drug release dependent on the content of MAA groups and crosslinking.

  9. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under...

  10. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under...

  11. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under...

  12. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as an acrylate ester (PMN P-96-824) is subject to reporting under...

  13. Hyaluronic Acid-Based Hydrogels Containing Covalently Integrated Drug Depots: Implication for Controlling Inflammation in Mechanically Stressed Tissues

    PubMed Central

    Xiao, Longxi; Tong, Zhixiang; Chen, Yingchao; Pochan, Darrin J.; Sabanayagam, Chandran R.; Jia, Xinqiao

    2013-01-01

    Synthetic hydrogels containing covalently-integrated soft and deformable drug depots capable of releasing therapeutic molecules in response to mechanical forces are attractive candidates for the treatment of degenerated tissues that are normally load bearing. Herein, radically crosslinkable block copolymer micelles (xBCM) assembled from an amphiphilic block copolymer consisting of hydrophilic poly(acrylic acid) (PAA) partially modified with 2-hydroxyethyl acrylate, and hydrophobic poly(n-butyl acryclate) (PnBA) were employed as the drug depots and the microscopic crosslinkers for the preparation of hyaluronic acid (HA)-based, hydrogels. HA hydrogels containing covalently integrated micelles (HAxBCM) were prepared by radical polymerization of glycidyl methacrylate (GMA)-modified HA (HAGMA) in the presence of xBCMs. When micelles prepared from the parent PAA-b-PnBA without any polymerizable double bonds were used, hydrogels containing physically entrapped micelles (HApBCM) were obtained. The addition of xBCMs to a HAGMA precursor solution accelerated the gelation kinetics and altered the hydrogel mechanical properties. The resultant HAxBCM gels exhibit an elastic modulus of 847 ± 43 Pa and a compressive modulus of 9.2 ± 0.7 kPa. Diffusion analysis of Nile Red (NR)-labeled xBCMs employing fluorescence correlation spectroscopy confirmed the covalent immobilization of xBCMs in HA networks. Covalent integration of dexamethasone (DEX)-loaded xBCMs in HA gels significantly reduced the initial burst release and provided sustained release over a prolonged period. Importantly, DEX release from HAxBCM gels was accelerated by intermittently-applied external compression in a strain-dependent manner. Culturing macrophages in the presence of DEX-releasing HAxBCM gels significantly reduced cellular production of inflammatory cytokines. Incorporating mechano-responsive modules in synthetic matrices offers a novel strategy to harvest mechanical stress present in the healing wounds

  14. Hyaluronic acid-based hydrogels containing covalently integrated drug depots: implication for controlling inflammation in mechanically stressed tissues.

    PubMed

    Xiao, Longxi; Tong, Zhixiang; Chen, Yingchao; Pochan, Darrin J; Sabanayagam, Chandran R; Jia, Xinqiao

    2013-11-11

    Synthetic hydrogels containing covalently integrated soft and deformable drug depots capable of releasing therapeutic molecules in response to mechanical forces are attractive candidates for the treatment of degenerated tissues that are normally load bearing. Herein, radically cross-linkable block copolymer micelles (xBCM) assembled from an amphiphilic block copolymer consisting of hydrophilic poly(acrylic acid) (PAA) partially modified with 2-hydroxyethyl acrylate, and hydrophobic poly(n-butyl acryclate) (PnBA) were employed as the drug depots and the microscopic cross-linkers for the preparation of hyaluronic acid (HA)-based, hydrogels. HA hydrogels containing covalently integrated micelles (HAxBCM) were prepared by radical polymerization of glycidyl methacrylate (GMA)-modified HA (HAGMA) in the presence of xBCMs. When micelles prepared from the parent PAA-b-PnBA without any polymerizable double bonds were used, hydrogels containing physically entrapped micelles (HApBCM) were obtained. The addition of xBCMs to a HAGMA precursor solution accelerated the gelation kinetics and altered the hydrogel mechanical properties. The resultant HAxBCM gels exhibit an elastic modulus of 847 ± 43 Pa and a compressive modulus of 9.2 ± 0.7 kPa. Diffusion analysis of Nile Red (NR)-labeled xBCMs employing fluorescence correlation spectroscopy confirmed the covalent immobilization of xBCMs in HA networks. Covalent integration of dexamethasone (DEX)-loaded xBCMs in HA gels significantly reduced the initial burst release and provided sustained release over a prolonged period. Importantly, DEX release from HAxBCM gels was accelerated by intermittently applied external compression in a strain-dependent manner. Culturing macrophages in the presence of DEX-releasing HAxBCM gels significantly reduced cellular production of inflammatory cytokines. Incorporating mechano-responsive modules in synthetic matrices offers a novel strategy to harvest mechanical stress present in the healing

  15. Technology and the use of acrylics for provisional dentine protection.

    PubMed

    Kapusevska, Biljana; Dereban, Nikola; Popovska, Mirjana; Nikolovska, Julijana; Radojkova Nikolovska, Vеrа; Zabokova Bilbilova, Efka; Mijoska, Aneta

    2013-01-01

    Acrylics are compounds polymerized from monomers of acrylic, metacrylic acid or acrylonitrates. The purpose of this paper is to present the technology and use of acrylics for provisional dentine protection in the practice of dental prosthodontics. For this reason, we followed 120 clinical cases from the everyday clinical practice, divided into 4 groups of 30 patients who needed prosthetic reconstruction. The first group included cases in which we applied celluloid crowns for dentine protection, for the second group we used acrylic teeth from a set of teeth for complete dentures; in the third and fourth groups the fabrication was done with the system of an impression matrix and the acrylic resin block technique respectively. In all the examined patients, the gingival index by Silness and Loe and the vitality of the dental pulp were verified clinically, after preparation and 8 days from the placement of the provisional crown. The value for dental sensitivity measured after preparation was 2.59, and 8 days after the placement of the provisional crown it bwas 3.1. From these results we can conclude that after the 8th day from the placement of the provisional crown, there was an adaptation period, characterized by a decrease in the painful sensations. The value of the Silness and Loe gingival index measured after the preparation was 1.34, and 8 days from the placement of the provisional crown was 0.94. The results inclined us to the fact that the provisional acrylic crowns facilitated the reparation of the periodontal tissue. PMID:24566021

  16. Auxin Biosynthesis: Are the Indole-3-Acetic Acid and Phenylacetic Acid Biosynthesis Pathways Mirror Images?1[OPEN

    PubMed Central

    Nichols, David S.; Smith, Jason; Chourey, Prem S.; McAdam, Erin L.; Quittenden, Laura

    2016-01-01

    The biosynthesis of the main auxin in plants (indole-3-acetic acid [IAA]) has been elucidated recently and is thought to involve the sequential conversion of Trp to indole-3-pyruvic acid to IAA. However, the pathway leading to a less well studied auxin, phenylacetic acid (PAA), remains unclear. Here, we present evidence from metabolism experiments that PAA is synthesized from the amino acid Phe, via phenylpyruvate. In pea (Pisum sativum), the reverse reaction, phenylpyruvate to Phe, is also demonstrated. However, despite similarities between the pathways leading to IAA and PAA, evidence from mutants in pea and maize (Zea mays) indicate that IAA biosynthetic enzymes are not the main enzymes for PAA biosynthesis. Instead, we identified a putative aromatic aminotransferase (PsArAT) from pea that may function in the PAA synthesis pathway. PMID:27208245

  17. Mixing It Up with Acrylics.

    ERIC Educational Resources Information Center

    Laird, Shirley

    1999-01-01

    Presents an art activity for fifth-grade students in which they learn about basic shapes and what happens when shapes overlap, draw seven overlapping geometric shapes, review the use of acrylic paint and mixing colors, and finally paint with primary colors. (CMK)

  18. In situ preparation of powder and the sorption behaviors of molecularly imprinted polymers through the complexation between polymer ion of methyl methacrylate/acrylic acid and Ca++ ion.

    PubMed

    Chough, Sung Hyo; Park, Kwang Ho; Cho, Seung Jin; Park, Hye Ryoung

    2014-09-01

    Molecularly imprinted polymer (MIP) powders were prepared using a simple complexation strategy between the polymer carboxylate groups and template molecule followed by metal cation cross-linking of residual polymer carboxylates. Polymer powders were formed in situ by templating carboxylic acid containing polymers with 4-ethylaniline (4-EA), followed by addition of an aqueous CaCl2 solution. The solution remained homogeneous. The powders were prepared by precipitation by slowly adding a non-solvent, H2O, to the mixture. The resulting particles were very porous with uptake capacity that approached the theoretical value. We suggest two types of complexes are formed between the template, 4-EA, and polymer. The isolated entry type forms well defined cavities for the template with high specific selectivity, while the adjacent entry type forms wider binding sites without specific sorption for isomeric molecules. To evaluate conditions for forming materials with high affinity and selectivity, three MIPs were prepared containing 0.5, 1.0, and 1.5 equivalents of template to the base polymer. The MIP containing 0.5 eq showed higher specific selectivity to 4-EA, but the MIP containing 1.5 eq had noticeably lower selectivity. The lower selectivity is attributed to poorly formed binding sites with little selective sorption to any isomer when the higher ratio of template was used. However at the lower ratio of template the isolated entry is preferably formed to produce well defined binding cavities with higher selectivity to template.

  19. Injectable pH- and temperature-responsive poly(N-isopropylacrylamide-co-propylacrylic acid) copolymers for delivery of angiogenic growth factors

    PubMed Central

    Garbern, Jessica C.; Hoffman, Allan S.; Stayton, Patrick S.

    2010-01-01

    A new sharply pH- and temperature-responsive hydrogel system was designed for delivering drugs to regions of local acidosis, as found in wound healing, tumor sites, or sites of ischemia. The reversible addition fragmentation chain transfer (RAFT) polymerization technique was used to synthesize copolymers of N-isopropylacrylamide (NIPAAM) and propylacrylic acid (PAA) with feed ratios of PAA between 0 and 20 mol %. The pH-responsive viscoelastic properties of these materials as a function of pH and temperature were quantified by rheometry. At physiologic pH (7.4) and 5 wt %, the polymer did not form gels, but rather remained soluble at temperatures as high as 50 °C. At lower pH values (pH ca. 5.5 and below) the polymer was liquid at 20 °C but exhibited a sol-gel phase transformation with increasing temperature and existed as a physical gel at 37 °C. Incorporation of the hydrophobic monomer, butyl acrylate, into the random copolymer raised the pH of gel formation to greater than 6.0 at 37 °C. Drug loading studies demonstrated that p(NIPAAm-co-PAA) hydrogels are able to maintain the bioactivity of basic fibroblast growth factor following storage in hydrogel for 40 h and can provide sustained pH-dependent release of vascular endothelial growth factor over a period of at least three weeks. This hydrogel system will thus gel at controllable acidic pH values upon injection, and is designed to undergo gradual dissolution as it performs its drug delivery function and the ischemic site returns to physiological pH. PMID:20509687

  20. Disinfection of water in recirculating aquaculture systems with peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) has become a favoured alternative to chlorination in the disinfection of municipal waste water in recent years. It is also commonly used in the food industry as a disinfectant. Based on PAA concentration, the disulfide linkage in enzymes and proteins of microorganisms can be bro...

  1. Controlling fungus on channel catfish eggs with peracetic acid

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is much interest in the use of peracetic acid (PAA) to treat pathogens in aquaculture. It is a relatively new compound and is approved for use in Europe, but not in the United States. This study determined the effectiveness of PAA for fungus control on channel catfish Ictalurus punctatus egg...

  2. The physiological significance of phenylacetic Acid in abscising cotton cotyledons.

    PubMed

    Suttle, J C; Mansager, E R

    1986-06-01

    The physiological role of phenylacetic acid (PAA) as an endogenous regulator of cotyledon abscission was examined using cotton (Gossypium hirsutum L. cv LG 102) seedlings. Application of 100 micromolar or more PAA to leafless cotyledon abscission-zone explants resulted in the retardation of petiole abscission and a decrease in the rise of ethylene evolution that normally accompanies aging of these explants in vitro. The partial inhibition of ethylene evolution in these explants by PAA was indirect since application of this compound stimulated short-term (<24 hours) ethylene production. PAA treatment partially suppressed the stimulation of petiole abscission elicited by either ethylene or abscisic acid. Both free and an acid-labile, bound form of PAA were identified in extracts prepared from cotyledons. No discernible pattern of changes in free or bound PAA was found during the course of ethylene-induced cotyledon abscission. Unlike indole-3-acetic acid, transport of PAA in isolated petiole segments was limited and exhibited little polarity. On the whole, these results are not consistent with the direct participation of PAA in the endogenous regulation of cotyledon abscission.

  3. Electrochemical characterization of aminated acrylic conducting polymer

    SciTech Connect

    Rashid, Norma Mohammad; Heng, Lee Yook; Ling, Tan Ling

    2015-09-25

    New attempt has been made to synthesize aminated acrylic conducting polymer (AACP) using precursor of phenylvinylsulfoxide (PVS). The process was conducted via the integration of microemulsion and photopolymerization techniques. It has been utilized for covalent immobilization of amino groups by the adding of N-achryiloxisuccinimide (NAS). Thermal eliminating of benzene sulfenic acids from PVS has been done at 250 °C to form electroactive polyacetylene (PA) segment. Characterization of AACP has been conducted using fourier transform infrared (FTIR), scanning electron microscopy (SEM) and linear sweep cyclic voltammetry (CV). A range of 0.3-1.25μm particle size obtained from SEM characterization. A quasi-reversible system performed as shown in electrochemical study.

  4. Electrochemical characterization of aminated acrylic conducting polymer

    NASA Astrophysics Data System (ADS)

    Rashid, Norma Mohammad; Heng, Lee Yook; Ling, Tan Ling

    2015-09-01

    New attempt has been made to synthesize aminated acrylic conducting polymer (AACP) using precursor of phenylvinylsulfoxide (PVS). The process was conducted via the integration of microemulsion and photopolymerization techniques. It has been utilized for covalent immobilization of amino groups by the adding of N-achryiloxisuccinimide (NAS). Thermal eliminating of benzene sulfenic acids from PVS has been done at 250 °C to form electroactive polyacetylene (PA) segment. Characterization of AACP has been conducted using fourier transform infrared (FTIR), scanning electron microscopy (SEM) and linear sweep cyclic voltammetry (CV). A range of 0.3-1.25μm particle size obtained from SEM characterization. A quasi-reversible system performed as shown in electrochemical study.

  5. Peracetic acid degradation in freshwater aquaculture systems and possible practical implications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is a highly reactive peroxygen compound with wide-ranging antimicrobial effects and is considered an alternative sanitizer to formaldehyde. Products containing PAA are available in solution with acetic acid and hydrogen peroxide to maintain the stability of the chemical, and it...

  6. Poly(amide-graft-acrylate) interfacial compounds

    NASA Astrophysics Data System (ADS)

    Zamora, Michael Perez

    Graft copolymers with segments of dissimilar chemistries have been shown to be useful in a variety of applications as surfactants, compatibilizers, impact modifiers, and surface modifiers. The most common route to well defined graft copolymers is through the use of macromonomers, polymers containing a reactive functionality and thus capable of further polymerization. However, the majority of the studies thus far have focused on the synthesis of macromonomers capable of reacting with vinyl monomers to form graft copolymers. This study focused on the synthesis of macromonomers capable of participating in condensation polymerizations. A chain transfer functionalization method was utilized. Cysteine was evaluated as a chain transfer agent for the synthesis of amino acid functionalized poly(acrylate) and poly(methacrylate) macromonomers. Low molar mass, functionalized macromonomers were produced. These macromonomers were proven to be capable of reacting with amide precursors to form poly(amide-g-acrylate) graft copolymers. Macromonomers and graft copolymers were characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) spectroscopy, elemental analysis (EA), inductively coupled plasma (ICP), and differential scanning calorimetry (DSC). The second part of this research involved poly(dimethacrylate) dental restorative materials. Volumetric shrinkage during the cure of these resins results in a poor interface between the resin and the remaining tooth structure, limiting the lifetime of these materials. Cyclic anhydrides were incorporated into common monomer compositions used in dental applications. Volume expansion from the ring opening hydrolysis of these anhydrides was shown to be feasible. The modified dental resins were characterized by swelling, extraction and ultraviolet spectroscopy (UV), and density measurements. Linear poLymers designed to model the crosslinked dental resins were

  7. Wavelength Shifters and Interactions of EDTA with Acrylic & LAB

    NASA Astrophysics Data System (ADS)

    Mohan, Yuvraj; SNO+ Collaboration

    2014-09-01

    The SNO + experiment, an upgrade to the Sudbury Neutrino Observatory, will use linear alkyl-benzene (LAB) liquid scintillator to probe new physics, including 0 νββ decay. Event detection efficiency is heavily affected by radioactive backgrounds, two sources being Rn-222 and Po-210 daughters, some of which has become embedded in the SNO + acrylic vessel after years underground. The leading candidate for polonium leaching is Ethylenediaminetetraacetic acid (EDTA). Before deployment on-site, EDTA's effects on the mechanical integrity of acrylic must be determined. It also must not be soluble in LAB or must be removed before scintillator fill of the vessel, as its presence would result in reduced light yield due to scattering. It was found that EDTA had negligible effects on the Young's Modulus of acrylic. EDTA is also slightly soluble in LAB, but can be completely removed by rinsing with water. Additionally, the study of the light yield and alpha/beta timing profiles of two wavelength shifters - bisMSB and perylene - is critical to determining which should be added to the 0 νββ isotope (tellurium) LAB cocktail. Small-scale results hint that perylene might be better, but this is being confirmed with larger-scale tests. The SNO + experiment, an upgrade to the Sudbury Neutrino Observatory, will use linear alkyl-benzene (LAB) liquid scintillator to probe new physics, including 0 νββ decay. Event detection efficiency is heavily affected by radioactive backgrounds, two sources being Rn-222 and Po-210 daughters, some of which has become embedded in the SNO + acrylic vessel after years underground. The leading candidate for polonium leaching is Ethylenediaminetetraacetic acid (EDTA). Before deployment on-site, EDTA's effects on the mechanical integrity of acrylic must be determined. It also must not be soluble in LAB or must be removed before scintillator fill of the vessel, as its presence would result in reduced light yield due to scattering. It was found that EDTA

  8. Chronic pulmonary dysfunction following acute inhalation of butyl acrylate.

    PubMed

    Bhardwaj, Ravindra; Ducatman, Alan; Finkel, Mitchell S; Petsonk, Edward; Hunt, Janet; Beto, Robert J

    2012-01-01

    Butyl Acrylate (BA) (2-propionic acid; CH2 = CHCOOC4H9) is a colorless liquid commonly used in impregnation agents and adhesives. Dermal contact with BA has previously been reported to cause moderate skin irritation with skin sensitizing potential in humans. Health effects of inhalation of BA have not been previously reported. Accordingly, we document the health conditions of a bystander, first responder and landfill worker exposed to butyl acrylate (BA) released to the atmosphere following a collision and roadside spill in October 1998. Retrospective data were collected via chart review and analyzed for exposure, symptoms, physical findings and radiological, laboratory and spirometry results over a ten-year period. All three patients had similar respiratory symptoms including a dramatic hacking cough and dyspnea. Findings included abnormal pulmonary function tests and breath sounds. These data underscore the potential hazards of BA inhalational exposure and the need to wear additional protective equipment. PMID:23472539

  9. Surface modification of nanoparticles for radiation curable acrylate clear coatings

    NASA Astrophysics Data System (ADS)

    Bauer, F.; Gläsel, H.-J.; Hartmann, E.; Bilz, E.; Mehnert, R.

    2003-08-01

    To obtain transparent, scratch and abrasion resistant coatings a high content of nanosized silica and alumina filler was embedded in radiation-curable acrylate formulations by acid catalyzed silylation using trialkoxysilanes. 29SiMAS NMR and MALDI-TOF mass spectrometry were employed to elucidate the structure of the surface-grafted methacryloxypropyl-, vinyl- and n-propyl-trimethoxysilane. In accordance with NMR findings, MALDI-TOF MS showed highly condensed oligomeric siloxanes of more than 20 monomeric silane units. A ladder-like structure of bound polysiloxanes is proposed rather than a simplified picture of tridentate silane bonding. Hence, silane coupling agents do not only modify the chemical nature of the filler surface but also strongly effect the rheological properties of the acrylate nanodispersions.

  10. Pre/post-strike atmospheric assessment system (PAAS)

    SciTech Connect

    Peglow, S. G., LLNL; Molitoris, J. D., LLNL

    1997-02-03

    The Pre/Post-Strike Atmospheric Assessment System was proposed to show the importance of local meteorological conditions in the vicinity of a site suspected of storing or producing toxic agents and demonstrate a technology to measure these conditions, specifically wind fields. The ability to predict the collateral effects resulting from an attack on a facility containing hazardous materials is crucial to conducting effective military operations. Our study approach utilized a combination of field measurements with dispersion modeling to better understand which variables in terrain and weather were most important to collateral damage predictions. To develop the PAAS wind-sensing technology, we utilized a combination of emergent and available technology from micro-Doppler and highly coherent laser systems. The method used for wind sensing is to probe the atmosphere with a highly coherent laser beam. As the beam probes, light is back-scattered from particles entrained in the air to the lidar transceiver and detected by the instrument. Any motion of the aerosols with a component along the beam axis leads to a Doppler shift of the received light. Scanning in a conical fashion about the zenith results in a more accurate and two-dimensional measurement of the wind velocity. The major milestones in the benchtop system development were to verify the design by demonstrating the technique in the laboratory, then scale the design down to a size consistent with a demonstrator unit which could be built to take data in the field. The micro-Doppler heterodyne system we developed determines absolute motion by optically mixing a reference beam with the return signal and has shown motion sensitivity to better than 1 cm/s. This report describes the rationale, technical approach and laboratory testing undertaken to demonstrate the feasibility and utility of a system to provide local meteorological data and predict atmospheric particulate motion. The work described herein was funded by

  11. 40 CFR 721.2805 - Acrylate ester.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylate ester. 721.2805 Section 721... Acrylate ester. Link to an amendment published at 79 FR 34637, June 18, 2014. (a) Chemical substance and... ester (PMN P-96-824) is subject to reporting under this section for the significant new uses...

  12. Stabilization of magnetorheological suspensions by polyacrylic acid polymers.

    PubMed

    Viota, J L; de Vicente, J; Durán, J D G; Delgado, A V

    2005-04-15

    This work is devoted to the synthesis and stabilization of magnetorheological suspensions constituted by monodisperse micrometer-sized magnetite spheres in aqueous media. The electrical double-layer characteristics of the solid/liquid interface were studied in the absence and presence of adsorbed layers of high molecular weight polyacrylic acids (PAA; Carbopol). Since the Carbopol-covered particles can be thought of as "soft" colloids, Ohshima's theory was used to gain information of the surface potential and the charge density of the polymer layer. The effect of the pH of the solution on the double-layer characteristics is related to the different conformations of the adsorbed molecules provoked by the dissociation of the acrylic groups present in polymer molecules. The stability of the suspensions was experimentally studied for different pH and polymer concentrations, and in the absence or presence of a weak magnetic field applied. The stability of the suspensions was explained using the classical DLVO theory of colloidal stability extended to account for hydration, steric, and magnetic interactions between particles. Diagrams of potential energy vs interparticle distance show the predominant effect of steric, hydrophilic/hydrophobic, and magnetic interactions on the whole stability of the system. The best conditions to obtain stable suspensions were found when strong steric and hydrophilic repulsions hinder the coagulation between polymer-covered particles, simultaneously avoiding sedimentation by the thickening effect of the polymer solution. When a not too high molecular weight PAA was employed in a low concentration, the task of a long-time antisettling effect compatible with the desired magnetic response of the fluid was achieved. PMID:15780292

  13. Differential sensitivities of the growth of Escherichia coli to acrylate under aerobic and anaerobic conditions and its effect on product formation.

    PubMed

    Arya, Ajay S; Lee, Sarah A; Eiteman, Mark A

    2013-11-01

    The effect of acrylate on the growth of Escherichia coli was determined under aerobic and anaerobic conditions in glucose-defined medium. Growth occurred with up to 35 mM acrylate under aerobic conditions but ceased at 5 mM acrylate under anaerobic conditions. This differential sensitivity can be attributed to inhibition of pyruvate formate lyase and/or pflB gene repression, as this enzyme is necessary for anaerobic growth of E. coli. The effect of acrylate on end-product distribution was also determined by growing E. coli first aerobically, then switching to anaerobic conditions. In the absence of acrylate, E. coli generated the typical distribution of mixed-acid products, with about 12 % of pyruvate being metabolically converted to lactate. In contrast, in the presence of 5 mM acrylate, E. coli converted 83 % of pyruvate to lactate, consistent with a reduction in pyruvate formate lyase activity.

  14. 76 FR 11965 - Peroxyacetic Acid; Amendment to an Exemption From the Requirement of a Tolerance

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-04

    ... degradates, including hydrogen peroxide (HP) and acetic acid (AA), in or on all food commodities, when PAA is..., colorless, organic compound that is formed, and only exists in equilibrium, with hydrogen peroxide and... hydrogen peroxide. PAA is always sold in solution with AA and HP to maintain stability of the...

  15. Pulse vs. continuous treatment: which is better for applying peracetic acid in RAS?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is a promising disinfectant in aquaculture. It is highly effective against various fish pathogens and also environmentally friendly due to harmless degradation residues. However, knowledge about potential adverse effects of PAA disinfection on fish is lacking; practical guidelin...

  16. MUTAGENICITY AND DISINFECTION BY-PRODUCTS IN SURFACE DRINKING WATER DISINFECTED WITH PERACETIC ACID

    EPA Science Inventory

    The aims of this research were to study the influence of peracetic acid (PAA) on the formation of mutagens in surface waters used for human consumption and to assess its potential application for the disinfection of drinking water. The results obtained using PAA were compared to ...

  17. Structure-activity relationships in the hydrolysis of acrylate and methacrylate esters by carboxylesterase in vitro.

    PubMed

    McCarthy, T J; Witz, G

    1997-01-15

    Acrylate esters are important chemicals in the plastics industry, whose toxicity is theorized to involve alkylation of critical cellular nucleophiles via the Michael addition. Carboxylesterase-mediated hydrolysis of acrylates may be a detoxification mechanism as the unsaturated acid produced is not electrophilic under physiological conditions. Using purified porcine liver carboxylesterase, the enzymatic hydrolysis of several acrylate esters was characterized to determine Km and Vmax values for each ester. The Km (microM) and Vmax (nmol/min) values observed for ethyl acrylate were 134 +/- 16 (S.D.) and 8.9 +/- 2.0, respectively. While the Km for ethyl methacrylate was not significantly different, the Vmax 5.5 +/- 2.5, was significantly lower compared with the corresponding value for ethyl acrylate. The Km and Vmax for butyl acrylate were 33.3 +/- 8.5 microM and 1.49 +/- 0.83 nmol/min, respectively, and the corresponding values for its alpha-methyl analog were not significantly different. The Km and Vmax for tetraethyleneglycol dimethacrylate were 39 +/- 15 microM and 2.9 +/- 1.0 nmol/min, respectively. The Vmax for ethyleneglycol dimethacrylate, 6.9 +/- 2.4 nmol/min, was significantly higher than that of the larger bifunctional ester tetraethyleneglycol dimethacrylate, but the Km was not significantly different. These results indicate that alpha-methyl substitution appears to have a minor effect in the enzymatic hydrolysis of acrylates, and suggest that the relative toxicity of acrylates is not due to differences in carboxylesterase-mediated hydrolysis.

  18. Acrylation of pre-irradiated polypropylene and its application for removal of organic pollutants

    NASA Astrophysics Data System (ADS)

    Said, Hossam M.; Sokker, Hesham H.; El-Hag Ali, Amr

    2010-04-01

    Reactive extrusion of pre-irradiated polypropylene (PP) at different doses of gamma radiation was studied in the presence of different concentrations of acrylic acid monomer (AAc). Preliminary investigations study the feasibility or removal of organic pollutants. The optical properties and surface morphology of the grafted polypropylene were observed by FT-IR, UV/vis and scanning electron microscopy (SEM). The affinity of this membrane to the basic dye was found to be increased with increase in the dose of gamma irradiation and the ratio of acrylic acid monomer (AAc).

  19. Radiopurity measurement of acrylic for DEAP-3600

    SciTech Connect

    Nantais, C. M.; Boulay, M. G.; Cleveland, B. T.

    2013-08-08

    The spherical acrylic vessel that contains the liquid argon target is the most critical detector component in the DEAP-3600 dark matter experiment. Alpha decays near the inner surface of the acrylic vessel are one of the main sources of background in the detector. A fraction of the alpha energy, or the recoiling nucleus from the alpha decay, could misreconstruct in the fiducial volume and result in a false candidate dark matter event. Acrylic has low levels of inherent contamination from {sup 238}U and {sup 232}Th. Another background of particular concern is diffusion of {sup 222}Rn during manufacturing, leading to {sup 210}Pb contamination. The maximum acceptable concentrations in the DEAP-3600 acrylic vessel are ppt levels of {sup 238}U and {sup 232}Th equivalent, and 10{sup −8} ppt {sup 210}Pb. The impurities in the bulk acrylic will be measured by vaporizing a large quantity of acrylic and counting the concentrated residue with ultra-low background HPGe detectors and a low background alpha spectrometer. An overview of the acrylic assay technique is presented.

  20. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false n-Alkylglutarimide/acrylic copolymers. 177.1060... Use Food Contact Surfaces § 177.1060 n-Alkylglutarimide/acrylic copolymers. n-Alkylglutarimide/acrylic...) Identity. For the purpose of this section, n-alkylglutarimide/acrylic copolymers are copolymers obtained...

  1. Growth inhibition of Aeromonas salmonicida and Yersinia ruckeri by disinfectants containing peracetic acid.

    PubMed

    Meinelt, Thomas; Phan, Thy-My; Behrens, Sascha; Wienke, Andreas; Pedersen, Lars-Flemming; Liu, Dibo; Straus, David L

    2015-04-01

    Peracetic acid (PAA) is a therapeutic agent used for disinfection in aquaculture, but it must be investigated thoroughly in order to mitigate diseases without harming the fish. Successful disinfectants (like PAA) should not leave dangerous residues in the environment in order to successfully contribute to sustainable aquaculture. The aim of our study was to compare the effectiveness of 6 commercial PAA products with different molecular PAA:H2O2 ratios to reduce bacterial growth of Aeromonas salmonicida and Yersinia ruckeri and to determine effective concentrations and exposure times. All products reduced colony-forming units (CFUs) of A. salmonicida and Y. ruckeri. Products with higher molecular PAA:H2O2 ratios inhibited growth better than products with lower molecular PAA:H2O2 ratios at the same PAA concentration; this indicates that H2O2 is not the driving force in the reduction of A. salmonicida and Y. ruckeri growth by PAA in vitro. The practical application of the products with high molecular PAA:H2O2 ratios should be prioritized if these pathogens are diagnosed.

  2. [Metabolism of pantothenic acid and its derivatives in animals deficient in this enzyme].

    PubMed

    Gurinovich, V A; Moiseenok, A G

    1987-01-01

    Distribution of [14C]labelled metabolites of pantothenic acid (PAA) has been studied in tissues of normal and PAA-deficient rats-weaners 6 h after single injection of the calcium pantothenate (PAA-Ca), calcium 4'-phosphopantothenate (PAA-Ca) or pantethine (PT) preparations. Essential differences in the intertissue distribution of vitamin derivatives to be injected are revealed against a background of a higher vitamin-retaining ability of the PAA-deficient tissues. A degree of radionuclides' biotransformation into CoA permits them to be arranged in the series: PPA-Ca greater than PAA-Ca greater than PT. In PAA-deficient animals which were injected labelled PPA-Ca up to 41% of the liver radioactivity is concentrated in the CoA fraction and the quantity of label in the composition of PAA-protein cytosolium complexes increases considerably. It is supposed that there is a special PAA-depositing system which provides the intracellular CoA biosynthesis. PMID:3686695

  3. Polyacrylic acid modified upconversion nanoparticles for simultaneous pH-triggered drug delivery and release imaging.

    PubMed

    Jia, Xuekun; Yin, Jinjin; He, Dinggeng; He, Xiaoxiao; Wang, Kemin; Chen, Mian; Li, Yuhong

    2013-12-01

    A poly(acrylicacid)-modified NaYF4:Yb, Er upconversion nanoparticles (PAA-UCNPs) with dual functions of drug delivery and release imaging have been successfully developed. The PAA polymer coated on the surface of UCNPs serve as a pH-sensitive nanovalve for loading drug molecules via electrostatic interaction. The drug-loading efficiency of the PAA-UCNPs was investigated by using doxorubicin hydrochloride (DOX) as a model anticancer drug to evaluate their potential as a delivery system. Results showed loading and releasing of DOX from PAA-UCNPs were controlled by varying pH, with high encapsulation rate at weak alkaline conditions and an increased drug dissociation rate in acidic environment, which is favorable for construct a pH-responsive controlled drug delivery system. The in vitro cytotoxicity test using HeLa cell line indicated that the DOX loaded PAA-UCNPs (DOX@PAA-UCNPs) were distinctly cytotoxic to HeLa cells, while the PAA-UCNPs were highly biocompatible and suitable to use as drug carriers. Furthermore, the upconversion fluorescence resonance energy transfer (UFRET) imaging through the two-photon laser scanning microscopy (TLSM) revealed the time course of intracellular delivery of DOX from DOX@PAA-UCNPs. Thus, PAA-UCNPs are effective for constructing pH-responsive controlled drug delivery systems for multi-functional cancer therapy and imaging. PMID:24266261

  4. Growth inhibition of Aeromonas salmonicida and Yersinia ruckeri by disinfectants containing peracetic acid.

    PubMed

    Meinelt, Thomas; Phan, Thy-My; Behrens, Sascha; Wienke, Andreas; Pedersen, Lars-Flemming; Liu, Dibo; Straus, David L

    2015-04-01

    Peracetic acid (PAA) is a therapeutic agent used for disinfection in aquaculture, but it must be investigated thoroughly in order to mitigate diseases without harming the fish. Successful disinfectants (like PAA) should not leave dangerous residues in the environment in order to successfully contribute to sustainable aquaculture. The aim of our study was to compare the effectiveness of 6 commercial PAA products with different molecular PAA:H2O2 ratios to reduce bacterial growth of Aeromonas salmonicida and Yersinia ruckeri and to determine effective concentrations and exposure times. All products reduced colony-forming units (CFUs) of A. salmonicida and Y. ruckeri. Products with higher molecular PAA:H2O2 ratios inhibited growth better than products with lower molecular PAA:H2O2 ratios at the same PAA concentration; this indicates that H2O2 is not the driving force in the reduction of A. salmonicida and Y. ruckeri growth by PAA in vitro. The practical application of the products with high molecular PAA:H2O2 ratios should be prioritized if these pathogens are diagnosed. PMID:25850398

  5. Crystal structure transformation in potassium acrylate

    NASA Astrophysics Data System (ADS)

    Pai Verneker, V. R.; Vasanthakumari, R.

    1983-10-01

    Potassium acrylate undergoes a reversible phase transformation around 335°K with an activation energy of 133 kcal/mole. Differential scanning calorimetry and high temperature X-ray powder diffraction techniques have been used to probe this phenomenon.

  6. Encapsulation of photocells with acrylic prepolymer

    SciTech Connect

    Avenel, M.; Evrard, P.; Leca, J.-P.

    1985-10-22

    Acrylic prepolymer comprising: from 10 to 50% by weight of units derived from at least one alkyl acrylate, the alkyl group having from 4 to 12 carbon atoms, from 30 to 60% by weight of units derived from at least one alkyl methacrylate, the alkyl group having from 1 to 5 carbon atoms, and from 10 to 40% by weight of units derived from methyl acrylate. The prepolymer is used to encapsulate photocells, connected to one another by conducting wires and positioned on a support plate, by casting a resin into the space located between the support plate and a second protective plate, the resin being obtained by mixing 100 parts of the acrylic prepolymer, from 0.1 to 4 parts of a vanadium arenesulphonate and from 0.5 to 4 parts of a free-radical initiator, at a temperature between 10 and 70 C. and for a sufficient time to solidify the polymeric resin at the temperature selected.

  7. Optimization of a Novel Binding Motif to (E)-3-(3,5-Difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)acrylic Acid (AZD9496), a Potent and Orally Bioavailable Selective Estrogen Receptor Downregulator and Antagonist.

    PubMed

    De Savi, Chris; Bradbury, Robert H; Rabow, Alfred A; Norman, Richard A; de Almeida, Camila; Andrews, David M; Ballard, Peter; Buttar, David; Callis, Rowena J; Currie, Gordon S; Curwen, Jon O; Davies, Chris D; Donald, Craig S; Feron, Lyman J L; Gingell, Helen; Glossop, Steven C; Hayter, Barry R; Hussain, Syeed; Karoutchi, Galith; Lamont, Scott G; MacFaul, Philip; Moss, Thomas A; Pearson, Stuart E; Tonge, Michael; Walker, Graeme E; Weir, Hazel M; Wilson, Zena

    2015-10-22

    The discovery of an orally bioavailable selective estrogen receptor downregulator (SERD) with equivalent potency and preclinical pharmacology to the intramuscular SERD fulvestrant is described. A directed screen identified the 1-aryl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole motif as a novel, druglike ER ligand. Aided by crystal structures of novel ligands bound to an ER construct, medicinal chemistry iterations led to (E)-3-(3,5-difluoro-4-((1R,3R)-2-(2-fluoro-2-methylpropyl)-3-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indol-1-yl)phenyl)acrylic acid (30b, AZD9496), a clinical candidate with high oral bioavailability across preclinical species that is currently being evaluated in phase I clinical trials for the treatment of advanced estrogen receptor (ER) positive breast cancer.

  8. Structural degradation of acrylic bone cements due to in vivo and simulated aging.

    PubMed

    Hughes, Kerry F; Ries, Michael D; Pruitt, Lisa A

    2003-05-01

    Acrylic bone cement is the primary load-bearing material used for the attachment of orthopedic devices to adjoining bone. Degradation of acrylic-based cements in vivo results in a loss of structural integrity of the bone-cement-prosthesis interface and limits the longevity of cemented orthopedic implants. The purpose of this study is to investigate the effect of in vivo aging on the structure of the acrylic bone cement and to develop an in vitro artificial aging protocol that mimics the observed degradation. Three sets of retrievals are examined in this study: Palacos brand cement retrieved from hip replacements, and Simplex brand cement retrieved from both hip and knee replacement surgeries. In vitro aging is performed using oxidative and acidic environments on three acrylic-based cements: Palacos, Simplex, and CORE. Gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR) are used to examine the evolution of molecular weight and chemical species within the acrylic cements due to both in vivo and simulated aging. GPC analysis indicates that molecular weight is degraded in the hip retrievals but not in the knee retrievals. Artificial aging in an oxidative environment best reproduces this degradation mechanism. FTIR analysis indicates that there exists a chemical evolution within the cement due to in vivo and in vitro aging. These findings are consistent with scission-based degradation schemes in the cement. Based on the results of this study, a pathway for structural degradation of acrylic bone cement is proposed. The findings from this investigation have broad applicability to acrylic-based cements and may provide guidance for the development of new bone cements that resist degradation in the body.

  9. Structure-function properties of starch graft poly(methyl acrylate)copolymers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spherulites, produced by steam jet-cooking high-amylose starch and oleic acid, were grafted with methyl acrylate, both before and after removal of un-complexed amylopectin. For comparison, granular high-amylose corn starch was graft polymerized in a similar manner. The amount of grafted and ungrafte...

  10. Structure-function properties of starch spherulites grafted with poly(methyl acrylate)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spherulites, produced by steam jet-cooking high-amylose starch and oleic acid, were grafted with methyl acrylate, both before and after removal of un-complexed amylopectin. For comparison, granular high-amylose corn starch was graft polymerized in a similar manner. The amount of grafted and ungrafte...

  11. Salts of phenylacetic acid and 4-hydroxyphenylacetic acid with Cinchona alkaloids: Crystal structures, thermal analysis and FTIR spectroscopy

    NASA Astrophysics Data System (ADS)

    Amombo Noa, Francoise M.; Jacobs, Ayesha

    2016-06-01

    Seven salts were formed with phenylacetic acid (PAA), 4-hydroxyphenylacetic acid (HPAA) and the Cinchona alkaloids; cinchonidine (CIND), quinidine (QUID) and quinine (QUIN). For all the structures the proton was transferred from the carboxylic acid of the PAA/HPAA to the quinuclidine nitrogen of the respective Cinchona alkaloid. For six of the salts, water was included in the crystal structures with one of these also incorporating an isopropanol solvent molecule. However HPAA co-crystallised with quinine to form an anhydrous salt, (HPAA-)(QUIN+). The thermal stability of the salts were determined and differential scanning calorimetry revealed that the (HPAA-)(QUIN+) salt had the highest thermal stability compared to the other salt hydrates. The salts were also characterized using Fourier transform infrared spectroscopy. (PAA-)(QUID+)·H2O and (PAA-)(QUIN+)·H2O are isostructural and Hirshfeld surface analysis was completed to compare the intermolecular interactions in these two structures.

  12. Allergic contact dermatitis to acrylates in disposable blue diathermy pads.

    PubMed Central

    Sidhu, S. K.; Shaw, S.

    1999-01-01

    We report 2 cases of elicitation of allergic contact dermatitis to acrylates from disposable blue diathermy pads used on patients who underwent routine surgery. Their reactions were severe, and took approximately 5 weeks to resolve. Both patients gave a prior history of finger tip dermatitis following the use of artificial sculptured acrylic nails, which is a common, but poorly reported, cause of acrylate allergy. Patch testing subsequently confirmed allergies to multiple acrylates present in both the conducting gel of disposable blue diathermy pads, and artificial sculptured acrylic nails. We advocate careful history taking prior to surgery to avoid unnecessary exposure to acrylates in patients already sensitized. Images Figure 1 Figure 2 PMID:10364952

  13. Precipitation of biomimetic fluorhydroxyapatite/polyacrylic acid nanostructures

    NASA Astrophysics Data System (ADS)

    Roche, Kevin J.; Stanton, Kenneth T.

    2015-01-01

    Ordered structures of fluorhydroxyapatite (FHA) nanoparticles that resemble the nanostructure of natural human enamel have been prepared. Wet precipitation in the presence of polyacrylic acid (PAA) was used, and the particle morphology was altered by varying several reaction conditions. High molecular weight PAA increased particle length from around 54 nm to several hundred nanometres, while maintaining particle width at 15 nm. PAA concentration and the order of mixing the reactants also influenced crystal morphology. Optimum conditions produced dense, aligned bundles of highly elongated nanorods, which are very similar to the hierarchical nanostructure of human tooth enamel.

  14. New blends of ethylene-butyl acrylate copolymers with thermoplastic starch. Characterization and bacterial biodegradation.

    PubMed

    Morro, A; Catalina, F; Corrales, T; Pablos, J L; Marin, I; Abrusci, C

    2016-09-20

    Ethylene-butyl acrylate copolymer (EBA) with 13% of butyl acrylate content was used to produce blends with 10, 30 and 60% of thermoplastic starch (TPS) plasticized with glycerol. Ethylene-acrylic acid copolymer (EAA) was used as compatibilizer at 20% content with respect to EBA. The blends were characterized by X-ray diffraction, ATR-Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), water-Contact Angle measurements (CA), Differential Scanning Calorimetry (DSC) and Stress-strain mechanical tests. Initiated autoxidation of the polymer blends was studied by chemiluminescence (CL) confirming that the presence of the polyolefin-TPS interphase did not substantially affect the oxidative thermostability of the materials. Three bacterial species have been isolated from the blend films buried in soil and identified as Bacillus subtilis, Bacillus borstelensis and Bacillus licheniformis. Biodegradation of the blends (28days at 45°C) was evaluated by carbon dioxide measurement using the indirect impedance technique. PMID:27261731

  15. [MORPHOLOGICAL FEATURES OF RAT MUCOUS MEMBRANE OF THE TONGUE EARLY AFFECTED BY ACRYLIC RESIN MONOMER].

    PubMed

    Davydenko, V; Nidzelskiy, M; Starchenko, I; Davydenko, A; Kuznetsov, V

    2016-03-01

    Base materials, made on the basis of various derivatives of acrylic and methacrylic acids, have been widely used in prosthetic dentistry. Free monomer, affecting the tissues of prosthetic bed and the whole body, is always found in dentures. Therefore, study of the effect of acrylic resins' monomer on mucous membrane of the tongue is crucial. Rat tongue is very similar to human tongue, and this fact has become the basis for selecting these animals to be involved into the experiment. The paper presents the findings related to the effect of "Ftoraks" base acrylic resin monomer on the state of rat mucous membrane of the tongue and its regeneration. The microscopy has found that the greatest changes in the mucous membrane of the tongue occur on day 3 and 7 day after applying the monomer and are of erosive and inflammatory nature. Regeneration of tongue epithelium slows down. PMID:27119844

  16. Nitrile Hydratase and Amidase from Rhodococcus rhodochrous Hydrolyze Acrylic Fibers and Granular Polyacrylonitriles

    PubMed Central

    Tauber, M. M.; Cavaco-Paulo, A.; Robra, K.-H.; Gübitz, G. M.

    2000-01-01

    Rhodococcus rhodochrous NCIMB 11216 produced nitrile hydratase (320 nkat mg of protein−1) and amidase activity (38.4 nkat mg of protein−1) when grown on a medium containing propionitrile. These enzymes were able to hydrolyze nitrile groups of both granular polyacrylonitriles (PAN) and acrylic fibers. Nitrile groups of PAN40 (molecular mass, 40 kDa) and PAN190 (molecular mass, 190 kDa) were converted into the corresponding carbonic acids to 1.8 and 1.0%, respectively. In contrast, surfacial nitrile groups of acrylic fibers were only converted to the corresponding amides. X-ray photoelectron spectroscopy analysis showed that 16% of the surfacial nitrile groups were hydrolyzed by the R. rhodochrous enzymes. Due to the enzymatic modification, the acrylic fibers became more hydrophilic and thus, adsorption of dyes was enhanced. This was indicated by a 15% increase in the staining level (K/S value) for C.I. Basic Blue 9. PMID:10742253

  17. Swelling, diffusion, network parameters and adsorption properties of IPN hydrogel of chitosan and acrylic copolymer.

    PubMed

    Mandal, Bidyadhar; Ray, Samit Kumar

    2014-11-01

    Interpenetrating network (IPN) type hydrogels of a biopolymer and a synthetic polymer were prepared from chitosan and crosslink copolymer of acrylic acid, sodium acrylate and hydroxyethyl methacrylate. Acrylic acid, sodium acrylate, hydroxyethyl methacrylate and N'N'-methylenebisacrylamide (MBA) monomers were free radically copolymerized and crosslinked in aqueous solution of chitosan. Several IPN hydrogels were prepared by varying concentrations of initiator, crosslinker (MBA) and weight% of chitosan . These hydrogels were characterized by free acid content, pH at point of zero charge (PZC), FTIR, DTA-TGA, SEM and XRD. The swelling and diffusion characteristics, network parameters and adsorption of cationic methyl violet (MV) and anionic congo red (CR) dyes by these hydrogels were studied. The hydrogels showed high adsorption (9.5-119 mg/g for CR and 9.2-98 mg/g for MV) and removal% (98-73% for CR and 94-66% for MV) over the feed concentration of 10-140 mg/l dye in water. The isotherms and kinetics of dye adsorption by the hydrogels were also studied.

  18. Imidization induced structural changes of 6FDA-ODA poly(amic acid) by two-dimensional (2D) infrared correlation spectroscopy

    NASA Astrophysics Data System (ADS)

    Seo, Hyemi; Chae, Boknam; Im, Ji Hyuk; Jung, Young Mee; Lee, Seung Woo

    2014-07-01

    Two-dimensional (2D) gradient mapping method and 2D correlation analysis of in situ FTIR spectra were used to probe the thermal imidization-induced spectral changes in 6FDA-ODA poly(amic acid) (PAA) films prepared by a reaction of 4,4‧-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) and 4,4‧-oxydianiline (ODA) in N,N‧-dimethylacetamide. Large spectral changes in the in situ FTIR spectra of 6FDA-ODA PAA film were observed in the range, 130-230 °C. The thermal imidization of 6FDA-ODA PAA films strongly affects the spectral changes in amic acid groups in the PAA unit. The spectral change in the amic acid groups occurred before those of the imide ring. The cyclic anhydrides, isoimdes and intermolecular links are present together with the imide ring in the thermally-cured 6FDA-ODA PAA films.

  19. Fish-friendly prophylaxis/disinfection in aquaculture: Low concentration of peracetic acid is stress-free to the carp (Cyprinus carpio) after repeated applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of peracetic acid (PAA) at low concentrations has been proved to be a broad functional and eco-friendly prophylaxis/disinfection method against various fish pathogens. Therefore, regular applications of low concentration PAA is sufficient to control (potential) pathogens in recirculatin...

  20. Modeling, Synthesis and Biological Evaluation of Potential Retinoid-X-Receptor (RXR) Selective Agonists: Novel Analogs of 4-[1-(3,5,5,8,8-Pentamethyl-5,6,7,8-tetrahydro-2-naphthyl)ethynyl]benzoic Acid (Bexarotene) and (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254)

    PubMed Central

    Jurutka, Peter W.; Kaneko, Ichiro; Yang, Joanna; Bhogal, Jaskaran S.; Swierski, Johnathon C.; Tabacaru, Christa R.; Montano, Luis A.; Huynh, Chanh C.; Jama, Rabia A.; Mahelona, Ryan D.; Sarnowski, Joseph T.; Marcus, Lisa M.; Quezada, Alexis; Lemming, Brittney; Tedesco, Maria A.; Fischer, Audra J.; Mohamed, Said A.; Ziller, Joseph W.; Ma, Ning; Gray, Geoffrey M.; van der Vaart, Arjan; Marshall, Pamela A.; Wagner, Carl E.

    2014-01-01

    Three unreported analogs of 4-[1-(3,5,5,8,8-pentamethyl-5-6-7-8-tetrahydro-2-naphthyl)ethynyl]benzoic acid (1), otherwise known as bexarotene, as well as four novel analogs of (E)-3-(3-(1,2,3,4-tetrahydro-1,1,4,4,6-pentamethylnaphthalen-7-yl)-4-hydroxyphenyl)acrylic acid (CD3254) are described, and evaluated for their retinoid-X-receptor (RXR)-selective agonism. Compound 1 has FDA approval as a treatment for cutaneous T-cell lymphoma (CTCL); though, treatment with 1 can elicit side-effects by disrupting other RXR-heterodimer receptor pathways. Of the 7 modeled novel compounds, all analogs stimulate RXR-regulated transcription in mammalian-2-hybrid and RXRE-mediated assays, possess comparable or elevated biological activity based on EC50 profiles, and retain similar or improved apoptotic activity in CTCL assays compared to 1. All novel compounds demonstrate selectivity for RXR and minimal crossover onto the retinoic-acid-receptor (RAR) compared to all-trans-retinoic acid, with select analogs also reducing inhibition of other RXR-dependent pathways (e.g., VDR-RXR). Our results demonstrate that further improvements in biological potency and selectivity of bexarotene can be achieved through rational drug design. PMID:24180745