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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. Ultrasonic Velocity, Viscosity and Refractive Index Investigation on Interacting Blend Solutions of PAA (Poly Acrylic Acid) and PVA (Poly Vinyl Alcohol) in Solvent DMSO (Di methyl Sulphoxide)

    NASA Astrophysics Data System (ADS)

    Nagamani, Chakrala

    2010-11-01

    The present study provides a great insight into the major new research areas like Plasma research (which is yielding a greater understanding of the universe) and Nano Technology Research (which provides many practical uses like Drug Delivery System). The Ultrasonic Velocities, Viscosities and Refractive indices of Poly (Acrylic Acid) and Poly (Vinyl Alcohol) blends in DMSO solutions have been measured over a wide range of composition, concentration and at different temperatures. The variation of Ultrasonic Velocity, derived acoustical parameters, adiabatic compressibility, acoustic impedance, Rao number, molar compressibility and relaxation strength with composition of blend solution was found not linear. This non-linearity has been attributed to incompatibility in conformity with the earlier findings. This behavior was confirmed by Viscometric and interaction parameters studies, as well as by investigation of Refractive index studies. These investigations offer an entirely new and simple approach to the study of the compatibility of polymer blends which is in general obtained by sophisticated techniques of thermal dynamic mechanical and electron microscopic analysis.

  3. 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.

  4. Dynamic peracetic acid (PAA) exposure, a treatment strategy against ectoparasites

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The search for alternative therapeutic agents is a difficult and laborious task. The use of peracetic acid (PAA) has recently been evaluated as an alternative compound for disinfection (Gustavino et al., 2005). In addition to having a broad antimicrobial spectrum, PAA does not contribute to the form...

  5. 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.

  6. Modification of polyethylene by radiation-induced graft polymerization of acrylic acid

    NASA Astrophysics Data System (ADS)

    Sidorova, L. P.; Aliev, A. D.; Zlobin, V. B.; Aliev, R. E.; Chalykh, A. E.; Kabanov, V. Ya.

    The kinetics investigation of the radiation-induced graft polymerization of acrylic acid onto low density polyethylene by direct method in aqueous solution in the presence of Mohr's salt, was performed. The technique of the contrasting of polyacrylic acid (PAA) graft layer was worked out by Ag +-ions. The structural and morphological peculiarities of grafted copolymers of PE with PAA were determined by the method of electron probe, and X-ray microanalysis by means of the electron microscopy.

  7. 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

  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. Release of triamcinolone acetonide from mucoadhesive polymer composed of chitosan and poly(acrylic acid) in vitro.

    PubMed

    Ahn, Jae-Soon; Choi, Hoo-Kyun; Chun, Myong-Kwan; Ryu, Jei-Man; Jung, Jae-Hee; Kim, Yue-Un; Cho, Chong-Su

    2002-03-01

    Transmucosal drug delivery (TMD) system using mucoadhesive polymer has been recently interested due to the rapid onset of action, high blood level, avoidance of the first-pass effect and the exposure of the drug to the gastrointestinal tract. A novel mucoadhesive polymer complex composed of chitosan and poly(acrylic acid) (PAA) was prepared by template polymerization of acrylic acid in the presence of chitosan for the TMD system. Triamcinolone acetonide (TAA) was loaded into the chitosan/PAA polymer complex film. TAA was evenly dispersed in chitosan, PAA polymer complex film without interaction with polymer complex. Release behavior of TAA from the mucoadhesive polymer film was dependent on time, pH, loading content of drug, and chitosan PAA ratio. The analysis of the drug release from the mucoadhesive film showed that TAA might be released from the chitosan/PAA polymer complex film through non-Fickian diffusion mechanism.

  10. Crosslinked carboxymethylchitosan-g-poly(acrylic acid) copolymer as a novel superabsorbent polymer.

    PubMed

    Chen, Yu; Tan, Hui-min

    2006-05-22

    A novel carboxymethylchitosan-g-poly(acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared through graft polymerization of acrylic acid onto the chain of carboxymethylchitosan and subsequent crosslinking. It was demonstrated by FTIR spectroscopy that acrylic acid had been graft polymerized with carboxymethylchitosan. The thermal stability of the polymer was characterized by thermogravimetric analysis. By studying the swelling ratio of the polymer synthesized under different conditions, optimization conditions were found for a polymer with the highest swelling ratio. The rate of water absorption of the polymer was high, and the swelling of the polymer fitted the process of first dynamics. The swelling ratio of the polymer was pH-dependent.

  11. Acute toxicity of peracetic acid (PAA) to Ichthyophthirius multifiliis theronts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is an antimicrobial disinfectant used in agriculture, food processing and medical facilities. It has recently been suggested as a means to control infestations of Ichthyophthirius multifiliis. The purpose of this study was to determine the acute toxicity of two products contai...

  12. Poly(acrylic acid)-grafted poly(N-isopropyl acrylamide) networks: preparation, characterization and hydrogel behavior.

    PubMed

    Yu, Rentong; Zheng, Sixun

    2011-01-01

    Poly(acrylic acid)-grafted poly(N-isopropylacrylamide) co-polymer networks (PNIPAAm-g-PAA) were prepared via the reversible addition-fragmentation transfer (RAFT) polymerization of N-isopropyl- acrylamide (NIPAAm) with trithiocarbonate-terminated PAA as a macromolecular chain-transfer agent in the presence of N,N-methylenebisacrylamide. The PNIPAAm-g-PAA co-polymer networks were characterized by means of Fourier transform infrared spectroscopy, differential scanning calorimetry and small-angle X-ray scattering. It is found that the PNIPAAm-g-PAA co-polymer networks were microphase-separated, in which the microdomains of PNIPAAm-PAA interpolymer complexes were dispersed into the PNIPAAm matrix. The PNIPAAm-g-PAA hydrogels displayed a dual response to temperature and pH values. The thermoresponsive properties of PNIPAAm-g-PAA networks were investigated. Below the volume phase transition temperatures, the PNIPAAm-g-PAA hydrogels possessed much higher swelling ratios than control PNIPAAm hydrogel. In terms of swelling, deswelling and reswelling tests, it is judged that the PNIPAAm-g-PAA hydrogels displayed faster response to the external temperature changes than control PNIPAAm hydrogel. The improved thermoresponsive properties of hydrogels are ascribed to the formation of PAA-grafted PNIPAAm networks, in which the water-soluble PAA chains behave as the hydrophiphilic tunnels and allow water molecules to go through and, thus, to accelerate the diffusion of water molecules.

  13. Poly(acrylic acid) nanogel as a substrate for cellulase immobilization for hydrolysis of cellulose.

    PubMed

    Ahmed, Ibrahim Nasser; Chang, Ray; Tsai, Wei-Bor

    2017-04-01

    Cellulase was adsorbed onto poly(acrylic acid), PAA, nanogel, that was fabricated via inverse-phase microemulsion polymerization. The PAA nanogel was around 150nm in diameter and enriched with carboxyl groups. The surface charge of PAA nanogel depended on the pHs of the environment and affected the adsorption of cellulase. The temperature stability of the immobilized cellulase was greatly enhanced in comparison to the free enzyme, especially at high temperature. At 80°C, the immobilized cellulase remained ∼75% of hydrolytic activity, in comparison to ∼55% for the free cellulase. Furthermore, the immobilized cellulase was more active than the free enzyme in acidic buffers. The immobilized cellulase could be recovered via centrifugation and can be used repeatedly, although the recovery ratio needs further improvement. In conclusion, PAA nanogel has the potential in the application of enzyme immobilization for biochemical processes.

  14. 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

  15. Removal of lead from aqueous solutions by a poly(acrylic acid)/bentonite nanocomposite

    NASA Astrophysics Data System (ADS)

    Rafiei, H. R.; Shirvani, M.; Ogunseitan, O. A.

    2016-11-01

    We synthesized a novel poly acrylic acid-organobentonite (PAA-Bent) nanocomposite by successive intercalation of cetyltrimethylammonium (CTA) surfactant and polyacrylic acid (PAA) into the bentonite (Bent) interlayer spaces. The surfactant-modified clay (CTA-Bent) and PAA-Bent nanocomposite were characterized by XRD and FT-IR techniques and used for removal of Pb(II) from aqueous solution. The XRD results confirmed the intercalation of CTA and PAA into the interlayer spaces of the bentonite increasing the d 001 spacing of the clay from 12.2 up to 38.9 Å. FT-IR analysis of the modified clay samples revealed the functional groups of CTA and PAA constituents alighted on the bentonite surfaces. Maximum Pb sorption capacity of the Bent and PAA-Bent predicted by Langmuir model were 52.3 and 93.0 mg g-1, respectively, showing that the synthesized nanocomposite superiorly adsorbed Pb from the solution as compared to the Bent. The maximum Pb removal efficiency of 99.6 % was achieved by the nanocomposite at 25 °C with <30 min contact time for a 7.5 g L-1 solid-to-liquid ratio and an initial metal concentration of 400 mg L-1. The results indicated that PAA-Bent nanocomposite can be efficiently used as a superadsorbent for the removal of Pb(II) from aqueous solution.

  16. 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.

  17. Protein polymer conjugates: improving the stability of hemoglobin with poly(acrylic acid).

    PubMed

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

    2011-06-21

    The synthesis, characterization, and evaluation of a novel polymer-protein conjugate are reported here. The covalent conjugation of high-molecular weight poly(acrylic acid) (PAA) to the lysine amino groups of met-hemoglobin (Hb) resulted in the covalent conjugation of Hb to PAA (Hb-PAA conjugate), as confirmed by dialysis and electrophoresis studies. The retention of native-like structure of Hb in Hb-PAA was established from Soret absorption, circular dichroism studies, and the redox activity of the iron center in Hb-PAA. The peroxidase-like activities of the Hb-PAA conjugate further confirmed the retention of Hb structure and biological activity. Thermal denaturation of the conjugate was investigated by differential scanning calorimetry and steam sterilization studies. The Hb-PAA conjugate indicated an improved denaturation temperature (T(d)) when compared to that of the unmodified Hb. One astonishing observation was that polymer conjugation significantly enhanced the Hb-PAA storage stability at room temperature. After 120 h of storage at room temperature in phosphate-buffered saline (PBS) at pH 7.4, for example, Hb-PAA retained 90% of its initial activity and unmodified Hb retained <60% of its original activity under identical conditions of buffer, pH, and temperature. Our conjugate demonstrates the key role of polymers in enhancing Hb stability via a very simple, efficient, general route. Water-swollen, lightly cross-linked, stable Hb-polymer nanogels of 100-200 nm were produced quickly and economically by this approach for a wide variety of applications.

  18. 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...

  19. 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...

  20. 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...

  1. 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... 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...

  2. 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...

  3. 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...

  4. 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.

  5. Disinfection of water in recirculating aquaculture systems with peracetic acid (PAA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disinfection behaviour of peracetic acid (PAA) in recirculating aquaculture systems (RAS) was investigated. Peracetic acid is a strong oxidizing agent found in various concentrations in different products. Three Wofasteril PAA products (E400 (c), Lspecical; AC 150) were tested in vitro for the...

  6. 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...

  7. Cisplatin-incorporated nanoparticles of poly(acrylic acid-co-methyl methacrylate) copolymer

    PubMed Central

    Lee, Kyung Dong; Jeong, Young-Il; Kim, Da Hye; Lim, Gyun-Taek; Choi, Ki-Choon

    2013-01-01

    Background Although cisplatin is extensively used in the clinical field, its intrinsic toxicity limits its clinical use. We investigated nanoparticle formations of poly(acrylic acid-co-methyl methacrylate) (PAA-MMA) incorporating cisplatin and their antitumor activity in vitro and in vivo. Methods Cisplatin-incorporated nanoparticles were prepared through the ion-complex formation between acrylic acid and cisplatin. The anticancer activity of cisplatin-incorporated nanoparticles was assessed with CT26 colorectal carcinoma cells. Results Cisplatin-incorporated nanoparticles have small particle sizes of less than 200 nm with spherical shapes. Drug content was increased according to the increase of the feeding amount of cisplatin and acrylic acid content in the copolymer. The higher acrylic acid content in the copolymer induced increase of particle size and decrease of zeta potential. Cisplatin-incorporated nanoparticles showed a similar growth-inhibitory effect against CT26 tumor cells in vitro. However, cisplatin-incorporated nanoparticles showed improved antitumor activity against an animal tumor xenograft model. Conclusion We suggest that PAA-MMA nanoparticles incorporating cisplatin are promising carriers for an antitumor drug-delivery system. PMID:23966778

  8. 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 ...

  9. 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.

  10. Peracetic acid (PAA) disinfection of primary, secondary and tertiary treated municipal wastewaters.

    PubMed

    Koivunen, J; Heinonen-Tanski, H

    2005-11-01

    The efficiency of peracetic acid (PAA) disinfection against enteric bacteria and viruses in municipal wastewaters was studied in pilot-scale. Disinfection pilot-plant was fed with the primary or secondary effluent of Kuopio municipal wastewater treatment plant or tertiary effluent from the pilot-scale dissolved air flotation (DAF) unit. Disinfectant doses ranged from 2 to 7 mg/l PAA in the secondary and tertiary effluents, and from 5 to 15 mg/l PAA in the primary effluents. Disinfection contact times were 4-27 min. Disinfection of secondary and tertiary effluents with 2-7 mg/l PAA and 27 min contact time achieved around 3 log reductions of total coliforms (TC) and enterococci (EC). PAA disinfection also significantly improved the hygienic quality of the primary effluents: 10-15 mg/l PAA achieved 3-4 log reductions of TC and EC, 5 mg/l PAA resulting in below 2 log reductions. F-RNA coliphages were more resistant against the PAA disinfection and around 1 log reductions of these enteric viruses were typically achieved in the disinfection treatments of the primary, secondary and tertiary effluents. Most of the microbial reductions occurred during the first 4-18 min of contact time, depending on the PAA dose and microorganism. The PAA disinfection efficiency remained relatively constant in the secondary and tertiary effluents, despite of small changes of wastewater quality (COD, SS, turbidity, 253.7 nm transmittance) or temperature. The disinfection efficiency clearly decreased in the primary effluents with substantially higher microbial, organic matter and suspended solids concentrations. The results demonstrated that PAA could be a good alternative disinfection method for elimination of enteric microbes from different wastewaters.

  11. Characterization of a planar poly(acrylic acid) brush as a materials coating for controlled protein immobilization.

    PubMed

    Hollmann, Oliver; Czeslik, Claus

    2006-03-28

    The adsorption of two different proteins at a planar poly(acrylic acid) (PAA) brush was studied as a function of the ionic strength of the protein solutions applying total internal reflection fluorescence (TIRF) spectroscopy. Planar PAA brushes were prepared with a grafting density of 0.11 nm(-2) and were characterized using X-ray reflectometry. Hen egg-white lysozyme and bovine serum albumin (BSA) were used as model proteins, which have a net positive and negative charge at neutral pH-values, respectively. It has been found that both proteins adsorb strongly at a planar PAA brush at low ionic strength. Whereas lysozyme interacts with a PAA brush under electrostatic attraction at neutral pH-values, BSA binds under electrostatic repulsion at pH > 5. Even at pH = 8, significant amounts of BSA are adsorbed to a planar PAA brush. In addition, the reversibility of BSA adsorption has been characterized. Dilution of a BSA solution leads to an almost complete desorption of BSA from a PAA brush at short contact times. When the ionic strength of the protein solutions is increased to about 100-200 mM, a planar PAA brush appears largely protein-resistant, regardless of the protein net charge. The results of this study indicate that the salt-dependent protein affinity of a PAA brush represents a unique effect that must be explained by a novel protein-binding mechanism. On the basis of a recent model, it is suggested that a release of counterions is the most probable driving force for protein adsorption at a PAA brush. In a general view, this study characterizes a planar PAA brush as a new materials coating for the controlled immobilization of proteins whose use in biotechnological applications appears to be rewarding.

  12. Biodegradability and mechanical properties of poly(butylene succinate) composites with finely dispersed hydrophilic poly(acrylic acid)

    NASA Astrophysics Data System (ADS)

    Mizuno, Sawako; Hotta, Atsushi

    2014-03-01

    Biodegradability and mechanical properties of aliphatic poly(butylene succinate) (PBS) films with finely dispersed hydrophilic poly(acrylic acid) (PAA) were investigated. First, 3.5 wt% of PAA was chemically grafted onto the surface of the PBS films (surface-grafted PBS) by photo grafting polymerization, and then the grafted PAA was homogeneously and finely dispersed into PBS by dissolving the surface-grafted PBS into chloroform before mixing and drying to get solid PAA-dispersed PBS. Degradation of these modified PBS was investigated using gel permeation chromatography (GPC) and tensile testing. According to the GPC results, it was found that the PAA-dispersed PBS had intermediate biodegradability with the intermediate water intake, and the reaction constant of PAA-dispersed PBS was in between those of untreated PBS and surface-grafted PBS, in fact 25% higher and 17% lower, respectively. The experimental results presented that the biodegradability of PBS could be well controlled by the dispersion of PAA, possibly leading to the widespread use of PBS for biodegradable polymers.

  13. Thermoresponsive gelling behavior of concentrated alumina suspensions containing poly(acrylic acid) and PEO-PPO-PEO copolymer.

    PubMed

    Kondo, Akira; Xu, Hui; Abe, Hiroya; Naito, Makio

    2012-05-01

    Thermoresponsive gelling behavior of concentrated alumina suspensions with poly(acrylic acid) (PAA) and triblock copolymer (PEO(101)-PPO(56)-PEO(101), Pluronic F127) was investigated as a function of PAA concentration (0.4-1.2 mass%) for ceramic solid free forming. The copolymer species assemble into micelles at temperatures above 15°C, yielding aqueous physical gel. In this study, the concentrated alumina aqueous suspensions (φ=35 vol%) were first prepared using the anionic dispersant of PAA, and then the copolymer species (10 mass%) were dissolved at a cooled temperature at 10°C. The addition of the copolymer species had a negligible influence on the adsorption state of PAA onto the alumina surfaces. The PAA concentration needed for the saturation adsorption on the alumina surfaces was ~0.6 mass%. When the PAA concentration was this value or slightly less, the suspension became gel state at 30°C from low viscous state at 10°C. The thermally induced alumina gel had excellent viscoelastic properties, and thereby the three dimensional periodic ceramic structures were successfully fabricated by a direct colloidal printing method that using the gels as "solid" inks at the room temperature. On the other hand, when it exceeded the saturation adsorption limit, the gelling behavior was not observed, indicating that the non-adsorbing PAA species may partly suppress the micellization of the copolymer on the heating.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. Poly(acrylic acid) modifying bentonite with in-situ polymerization for removing lead ions.

    PubMed

    He, Y F; Zhang, L; Yan, D Z; Liu, S L; Wang, H; Li, H R; Wang, R M

    2012-01-01

    In this paper, a new kind of poly(acrylic acid) modified clay adsorbent, the poly(acrylic acid)/bentonite composite (PAA/HB) was prepared by in-situ polymerization, and utilized to remove lead(II) ions from solutions. The maximum adsorption of adsorbent is at pH 5 for metal ions, whereas the adsorption starts at pH 2. The effects of contact time (5-60 min), initial concentration of metal ions (200-1,000 mg/L) and adsorbent dosage (0.04-0.12 g/100 mL) have been reported in this article. The experimental data were investigated by means of kinetic and equilibrium adsorption isotherms. The kinetic data were analyzed by the pseudo-first-order and pseudo-second-order equation. The experimental data fitted the pseudo-second-order kinetic model very well. Langmuir and Freundlich isotherms were tried for the system to better understand the adsorption isotherm process. The maximal adsorption capacity of the lead(II) ions on the PAA/HB, as calculated from the Langmuir model, was 769.2 mg/g. The results in this study indicated that PAA/HB was an attractive candidate for removing lead(II) (99%).

  3. 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.

  4. Poly(Acrylic Acid-b-Styrene) Amphiphilic Multiblock Copolymers as Building Blocks for the Assembly of Discrete Nanoparticles

    PubMed Central

    Greene, Anna C.; Zhu, Jiahua; Pochan, Darrin J.; Jia, Xinqiao; Kiick, Kristi L.

    2011-01-01

    In order to expand the utility of current polymeric micellar systems, we have developed amphiphilic multiblock copolymers containing alternating blocks of poly(acrylic acid) and poly(styrene). Heterotelechelic poly(tert-butyl acrylate-b-styrene) diblock copolymers containing an α-alkyne and an ω-azide were synthesized by atom transfer radical polymerization (ATRP), allowing control over the molecular weight while maintaining narrow polydispersity indices. The multiblock copolymers were constructed by copper-catalyzed azide-alkyne cycloaddition of azide-alkyne end functional diblock copolymers which were then characterized by 1H NMR, FT-IR and SEC. The tert-butyl moieties of the poly(tert-butyl acrylate-b-styrene) multiblock copolymers were easily removed to form the poly(acrylic acid-b-styrene) multiblock copolymer ((PAA-PS)9), which contained up to 9 diblock repeats. The amphiphilic multiblock (PAA-PS)9 (Mn = 73.3 kg/mol) was self-assembled by dissolution into tetrahydrofuran and extensive dialysis against deionized water for 4 days. The critical micelle concentration (CMC) for (PAA-PS)9 was determined by fluorescence spectroscopy using pyrene as a fluorescent probe and was found to be very low at 2 × 10-4 mg/mL. The (PAA-PS)9 multiblock was also analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter of the particles was found to be 11 nm. Discrete spherical particles were observed by TEM with an average particle diameter of 14 nm. The poly(acrylic acid) periphery of the spherical particles should allow for future conjugation of biomolecules. PMID:21552373

  5. 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.

  6. A carbonate controlled-addition method for amorphous calcium carbonate spheres stabilized by poly(acrylic acid)s.

    PubMed

    Huang, Shu-Chen; Naka, Kensuke; Chujo, Yoshiki

    2007-11-20

    Stable amorphous calcium carbonate (ACC) composite particle with a size-controlled monodispersed sphere was obtained by a new simple carbonate controlled-addition method by using poly(acrylic acid) (PAA) (Mw = 5000), in which an aqueous ammonium carbonate solution was added into an aqueous solution of PAA and CaCl2 with a different time period. The obtained ACC composite products consist of about 50 wt % of ACC, 30 wt % of PAA, and H2O. Average particle sizes of the ACC spheres increased from (1.8 +/- 0.4) x 102 to (5.5 +/- 1.2) x 102 nm with an increase of the complexation time of the PAA-CaCl2 solution from 3 min to 24 h, respectively. The ACC formed from the complexation time for 3 min was stable for 10 days with gentle stirring as well as 3 months under a quiescent condition in the aqueous solution. Moreover, the ACC was also stable at 400 degrees C. Stability of the amorphous phase decreased with an increase of the complexation time of the PAA-CaCl2 solution. No ACC was obtained when the lower molar mass PAAs (Mw = 1200 and 2100) were used. In the higher molar mass case (Mw = 25 000), a mixture of the amorphous phase and vaterite and calcite crystalline product was produced. The present results demonstrate that the interaction and the reaction kinetics of the PAA-Ca2+-H2O complex play an important role in the mineralization of CaCO3.

  7. 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

  8. The effects of the thiolation with thioglycolic acid and l-cysteine on the mucoadhesion properties of the starch-graft-poly(acrylic acid).

    PubMed

    Gök, M Koray; Demir, Kamber; Cevher, Erdal; Özsoy, Yıldız; Cirit, Ümüt; Bacınoğlu, Süleyman; Özgümüş, Saadet; Pabuccuoğlu, Serhat

    2017-05-01

    The aim of this study is to investigate the effects of the thiolation on the mucoadhesion characteristics of the gelatinized and crosslinked wheat starch-graft-poly(acrylic acid) [(WS-g-PAA)gc] for potential use in drug delivery via vaginal route. Thiolation of (WS-g-PAA)gc was first time realized using l-cysteine hydrochloride monohydrate (CyS) and thioglycolic acid (TGA). These conjugates [(WS-g-PAA)gcth] were characterized using FTIR. The free SH group, mucoadhesion, cytotoxicity characteristics and the mechanism of the thiolation were also evaluated. To obtain fundamental data for possible application such as drug carrier, in vitro and in vivo progesterone release profiles from the mucoadhesive tablet formulations were also determined. The results showed that, vaginal tablet containing (WS-g-PAA)gc-TGA, which has not contain free SH groups in its structure, displays higher mucoadhesion than (WS-g-PAA)gc and (WS-g-PAA)gc-CyS. This tablet formulation can also be used as a drug carrier in vaginal applications.

  9. Ear-like poly (acrylic acid)-activated carbon nanocomposite: A highly efficient adsorbent for removal of Cd(II) from aqueous solutions.

    PubMed

    Ge, Huacai; Wang, Jincui

    2017-02-01

    Poly (acrylic acid) modified activated carbon nanocomposite (PAA-AC) was synthesized. The structure and morphology of this nanocomposite were characterized by FTIR, SEM, TEM, XRD and Zeta potential. The adsorption of some heavy metal ions on PAA-AC was studied. The characterization results indicated that PAA-AC was a novel and ear-like nanosheet material with the thickness of about 40 nm and the diameter of about 300 nm. The adsorption results exhibited that the introduction of carboxyl groups into activated carbon evidently increased the uptake for heavy metal ions and the nanocomposite had maximum uptake for Cd(II). Various variables affecting adsorption of PAA-AC for Cd(II) were systematically explored. The maximum capacity and equilibrium time for adsorption of Cd(II) by PAA-AC were 473.2 mg g(-1) and 15 min. Moreover, the removal of Cd(II) for real electroplating wastewater by PAA-AC could reach 98.5%. These meant that the removal of Cd(II) by PAA-AC was highly efficient and fast. The sorption kinetics and isotherm fitted well with the pseudo-second-order model and Langmuir model, respectively. The adsorption mainly was a chemical process by chelation. Thermodynamic studies revealed that the adsorption was a spontaneous and endothermic process. The results revealed that PAA-AC could be considered as a potential candidate for Cd(II) removal.

  10. Characterization of bioactive RGD peptide immobilized onto poly(acrylic acid) thin films by plasma polymerization

    NASA Astrophysics Data System (ADS)

    Seo, Hyun Suk; Ko, Yeong Mu; Shim, Jae Won; Lim, Yun Kyong; Kook, Joong-Ki; Cho, Dong-Lyun; Kim, Byung Hoon

    2010-11-01

    Plasma surface modification can be used to improve the surface properties of commercial pure Ti by creating functional groups to produce bioactive materials with different surface topography. In this study, a titanium surface was modified with acrylic acid (AA) using a plasma treatment and immobilized with bioactive arginine-glycine-aspartic acid (RGD) peptide, which may accelerate the tissue integration of bone implants. Both terminals containing the -NH2 of RGD peptide sequence and -COOH of poly(acrylic acid) (PAA) thin film were combined with a covalent bond in the presence of 1-ethyl-3-3-dimethylaminopropyl carbodiimide (EDC). The chemical structure and morphology of AA film and RGD immobilized surface were investigated by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR), atomic force microscopy (AFM), and scanning electron microscopy (SEM). All chemical analysis showed full coverage of the Ti substrate with the PAA thin film containing COOH groups and the RGD peptide. The MC3T3-E1 cells were cultured on each specimen, and the cell alkaline phosphatase (ALP) activity were examined. The surface-immobilized RGD peptide has a significantly increased the ALP activity of MC3T3-E1 cells. These results suggest that the RGD peptide immobilization on the titanium surface has an effect on osteoblastic differentiation of MC3T3-E1 cells and potential use in osteo-conductive bone implants.

  11. 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.

  12. Mechanism of poly(acrylic acid) acceleration of antithrombin inhibition of thrombin: implications for the design of novel heparin mimics.

    PubMed

    Monien, Bernhard H; Cheang, Kai I; Desai, Umesh R

    2005-08-11

    The bridging mechanism of antithrombin inhibition of thrombin is a dominant mechanism contributing a massive approximately 2500-fold acceleration in the reaction rate and is also a key reason for the clinical usage of heparin. Our recent study of the antithrombin-activating properties of a carboxylic acid-based polymer, poly(acrylic acid) (PAA), demonstrated a surprisingly high acceleration in thrombin inhibition (Monien, B. H.; Desai, U. R. J. Med. Chem. 2005, 48, 1269). To better understand this interesting phenomenon, we have studied the mechanism of PAA-dependent acceleration in antithrombin inhibition of thrombin. Competitive binding studies with low-affinity heparin and a heparin tetrasaccharide suggest that PAA binds antithrombin in both the pentasaccharide- and the extended heparin-binding sites, and these results are corroborated by molecular modeling. The salt-dependence of the K(D) of the PAA-antithrombin interaction shows the formation of five ionic interactions. In contrast, the contribution of nonionic forces is miniscule, resulting in an interaction that is significantly weaker than that observed for heparins. A bell-shaped profile of the observed rate constant for antithrombin inhibition of thrombin as a function of PAA concentration was observed, suggesting that inhibition proceeds through the "bridging" mechanism. The knowledge gained in this mechanistic study highlights important rules for the rational design of orally available heparin mimics.

  13. 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.

  14. 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.

  15. Nanostructure of a poly(acrylic acid) brush and its transition in the amphiphilic diblock copolymer monolayer on the water surface.

    PubMed

    Matsuoka, Hideki; Suetomi, Yoshiko; Kaewsaiha, Ploysai; Matsumoto, Kozo

    2009-12-15

    The nanostructure and its transition of in a poly(acrylic acid) (PAA) brush in the water surface monolayers of poly(hydrogenated isoprene)-b-poly(acrylic acid) with different block lengths and block ratios were investigated by X-ray reflectivity as a function of surface pressure (brush density) and salt concentration in the subphase. The PAA brush showed the same behavior after salt addition as did the poly(methacrylic acid) (PMAA) brush, which was investigated previously. The brush chains expanded and then shrunk after passing the maximum with increasing added salt concentration. This behavior could be explained by the change in electric charges on the PAA brush chains as was observed on the PMAA brush. The PAA brush chains showed a critical brush density, where there was a transition between the carpet layer only and carpet + brush layer structures, as did the PMAA and poly(styrene sulfonic acid) (PSS) brushes. The critical brush density was about 0.4 chains nm(-2), which was higher than that of the PSS brush, a strong acid brush, and was close to that of the PMAA brush, a weak acid brush. However, the critical brush density of the PAA brush was independent of the hydrophilic chain length whereas that of the PMAA brush decreased with increasing PMAA chain length. In addition, the PAA brush had a thicker carpet layer than the PSS and PMAA brushes. Hence, the mechanism of PAA brush formation was predicted to be different from that of not only the PSS brush (strong acid brush) but also the PMAA brush.

  16. Fabrication and mechanical characterization of graphene oxide-reinforced poly (acrylic acid)/gelatin composite hydrogels

    NASA Astrophysics Data System (ADS)

    Faghihi, Shahab; Gheysour, Mahsa; Karimi, Alireza; Salarian, Reza

    2014-02-01

    Hydrogels have found many practical uses in drug release, wound dressing, and tissue engineering. However, their applications are restricted due to their weak mechanical properties. The role of graphene oxide nanosheets (GONS) as reinforcement agent in poly (acrylic acid) (PAA)/Gelatin (Gel) composite hydrogels is investigated. Composite hydrogels are synthesized by thermal initiated redox polymerization method. Samples are then prepared with 20 and 40 wt. % of PAA, an increasing amount of GONS (0.1, 0.2, and 0.3 wt. %), and a constant amount of Gel. Subsequently, cylindrical hydrogel samples are subjected to a series of compression tests in order to measure their elastic modulus, maximum stress and strain. The results exhibit that the addition of GONS increases the Young's modulus and maximum stress of hydrogels significantly as compared with control (0.0 wt. % GONS). The highest Young's modulus is observed for hydrogel with GO (0.2 wt. %)/PAA (20 wt. %), whereas the highest maximum stress is detected for GO (0.2 wt. %)/PAA (40 wt. %) specimen. The addition of higher amounts of GONS leads to a decrease in the maximum stress of the hydrogel GO (0.3 wt. %)/PAA (40 wt. %). No significant differences are detected for the maximum strain among the hydrogel samples, as the amount of GONS increased. These results suggest that the application of GONS could be used to improve mechanical properties of hydrogel materials. This study may provide an alternative for the fabrication of low-cost graphene/polymer composites with enhanced mechanical properties beneficial for tissue engineering applications.

  17. Acute toxicity of peracetic acid (PAA) formulations to Ichthyophthirius multifiliis theronts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is an antimicrobial disinfectant used in agriculture, food processing and medical facilities. It has recently been suggested as a means to control infestations of Ichthyophthirius multifiliis. The purpose of this study was to determine the acute toxicity of two products contai...

  18. Poly(acrylic acid) modified calcium phosphate cements: the effect of the composition of the cement powder and of the molecular weight and concentration of the polymeric acid.

    PubMed

    Majekodunmi, A O; Deb, S

    2007-09-01

    Polymer modified calcium phosphate cements made with cement powders of varying tetracalcium phosphate [TTCP] content were prepared using two different molecular weight fractions of poly(acrylic acid) at four different concentrations. The ratio of the precursors (TTCP:DCPA) in the cement powder was found to influence the initial setting which decreased with increasing concentration of TTCP in the powder phase. It was also observed that cements derived from the higher molecular weight containing PAA yielded significantly (P < 0.05) shorter initial setting time (Ti) than cements containing the lower molecular weight, poly(acrylic acid) [GE7 PAA] The effect of the varying the TTCP content in the three different cement types PCPC-A, PCPC-B and PCPC-C showed that the trends of the compressive strength were specific to the concentration and molecular weight of the poly (acrylic acid). A 20% concentration of Glascol-E7 with a cement powder composed of an equimolar ratio of precursors (PCPC-B) resulted in optimal compressive strength within the range investigated. The TTCP content of the cement powder could also be varied to improve the diametral tensile strengths of the cements; the specific effects however, were again governed by both the concentration and molecular weight of the constituent poly (acrylic acid). The influence of TTCP on both the initial setting time and diametral tensile strength was related to the Ca (2+) ion concentration, which determined the rate and amount of cross-linking in the cement.

  19. Nanoassembled thin film gas sensors. III. Sensitive detection of amine odors using TiO2/poly(acrylic acid) ultrathin film quartz crystal microbalance sensors.

    PubMed

    Lee, Seung-Woo; Takahara, Naoki; Korposh, Sergiy; Yang, Do-Hyeon; Toko, Kiyoshi; Kunitake, Toyoki

    2010-03-15

    Quartz crystal microbalance (QCM) gas sensors based on the alternate adsorption of TiO(2) and polyacrilic acid (PAA) were developed for the sensitive detection of amine odors. Individual TiO(2) gel layers could be regularly assembled with a thickness of approximately 0.3 nm by the gas-phase surface sol-gel process (GSSG). The thickness of the poly(acrylic acid) (PAA) layer is dependent on its molecular weight, showing different thicknesses of approximately 0.4 nm for PAA(25) (Mw 250,000) and 0.6-0.8 nm for PAA(400) (Mw 4,000,000). The QCM sensors showed a linear response to ammonia in the concentration range 0.3-15 ppm, depending on the deposition cycle of the alternate TiO(2)/PAA layer. The ammonia binding is based on the acid-base interaction to the free carboxylic acid groups of PAA and the limit of detection (LOD) of the 20-cycle TiO(2)/PAA(400) film was estimated to be 0.1 ppm when exposed to ammonia. The sensor response was very fast and stable in a wide relative humidity (rH) range of 30-70%, showing almost the same frequency changes at a given concentration of ammonia. Sensitivity to n-butylamine and ammonia was higher than to pyridine, which is owing to the difference of molecular weight and basicity of the amine analytes. The alternate TiO(2)/PAA(400) films have a highly effective ability to capture amine odors, and the ambient ammonia concentration of 15 ppm could be condensed up to approximately 20,000 ppm inside the films.

  20. 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

  1. Layer-by-layer structured films of TiO2 nanoparticles and poly(acrylic acid) on electrospun nanofibres

    NASA Astrophysics Data System (ADS)

    Ding, Bin; Kim, Jinho; Kimura, Eiji; Shiratori, Seimei

    2004-08-01

    We report a new approach for fabricating layer-by-layer (LBL) structured ultrathin hybrid films on electrospun nanofibres. Oppositely charged anatase TiO2 nanoparticles and poly(acrylic acid) (PAA) were alternately deposited on the surface of negatively charged cellulose acetate (CA) nanofibres using the electrostatic LBL self-assembly technique. The fibrous mats were characterized by wide-angle x-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy and Brunauer-Emmett-Teller (BET) surface area techniques. The crystalline phase of anatase TiO2 remained unchanged in the resultant TiO2/PAA films coated on CA fibrous mats. Moreover, the TiO2/PAA film coated fibres showed rough surfaces with grains due to the deposition of aggregated TiO2 particles. The average diameter of the fibres increased from 344 to 584 nm and the BET surface area of the fibrous mats increased from 2.5 to 6.0 m2 g-1 after coating with five bilayers of TiO2/PAA films.

  2. Acrylamide/acrylic acid copolymers for cement fluid loss control

    SciTech Connect

    McKenzie, L.F.; McElfresh, P.M.

    1982-01-01

    Acrylamide/acrylic acid copolymers are considered as effective fluid loss control additives in a wide range of oil well cements. Unlike HEC based fluid loss aditives, these copolymers can be used with calcium chloride accelerator without significantly influencing fluid loss control. Another advantage of the copolymers is that the amount of fluid loss for a given concentration of polymer remains relatively constant over a wide range of temperatures. The use of acrylamide/acrylic acid copolymers has generally been restricted to wells below 60 degree C BHCT. Above that temperature chemical changes in the copolymer often lead to retardation of the cement. This paper presents data related to the use of acrylamide/acrylic acid copolymers as fluid loss control agents in oil well cementing. A comparison of these polymers with HEC based fluid loss control additives is made. In addition, data related to the cause of acrylamide/acrylic acid copolymer retarding effects is presented. 4 refs.

  3. 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.

  4. 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...

  5. 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.

  6. Preparation of porous carboxymethyl chitosan grafted poly (acrylic acid) superabsorbent by solvent precipitation and its application as a hemostatic wound dressing.

    PubMed

    Chen, Yu; Zhang, Yong; Wang, Fengju; Meng, Weiwei; Yang, Xinlin; Li, Peng; Jiang, Jianxin; Tan, Huimin; Zheng, Yongfa

    2016-06-01

    The volume phase transition of a hydrogel initiated by shrinking may result in complex patterns on its surface. Based on this unique property of hydrogel, we have developed a novel solvent precipitation method to prepare a kind of novel superabsorbent polymers with excellent hemostatic properties. A porous carboxymethyl chitosan grafted poly (acrylic acid) (CMCTS-g-PAA) superabsorbent polymer was prepared by precipitating CMCTS-g-PAA hydrogel with ethanol. Its potential application in hemostatic wound dressing was investigated. The results indicate that the modified superabsorbent polymer is non-cytotoxic. It showed a high swelling capacity and better hemostatic performance in the treatments of hemorrhage model of ear artery, arteria cruralis and spleen of the New Zealand white rabbit than the unmodified polymer and other commonly used clinic wound dressings. The hemostatic mechanism of the porous CMCTS-g-PAA polymer was also discussed.

  7. 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.

  8. 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.

  9. Transport of poly(acrylic acid) coated 2-line ferrihydrite nanoparticles in saturated aquifer sediments for environmental remediation

    NASA Astrophysics Data System (ADS)

    Xiang, Aishuang; Zhou, Sheng; Koel, Bruce E.; Jaffé, Peter R.

    2014-04-01

    Groundwater remediation using iron oxide and zero-valent iron nanoparticles (NPs) can be effective, but is limited in many applications due to the NP strong retention in groundwater-saturated porous media after injection, the passivation of the porous surface, and the high cost of nanomaterials versus macro scale iron. In this study, we investigated transport of bare and polymer-coated 2-line ferrihydrite NPs (30-300 nm) in saturated aquifer sediments. The influence of poly(acrylic acid) (PAA) polymer coatings was studied on the colloidal stability and transport in sediments packed column tests simulating groundwater flow in saturated sediments. In addition, the influence of calcium cations was investigated by transport measurements using sediments with calcium concentrations in the aqueous phase ranging from 0.5 (typical for most sediments) to 2 mM. Measurements were also made of zeta potential, hydrodynamic diameter, polymer adsorption and desorption properties, and bio-availability of PAA-coated NPs. We found that NP transport through the saturated aquifer sediments was improved by PAA coating and that the transport properties could be tuned by adjusting the polymer concentration. We further discovered that PAA coatings enhanced NP transport, compared to bare NPs, in all calcium-containing experiments tested, however, the presence of calcium always exhibited a negative effect on NP transport. In tests of bioavailability, the iron reduction rate of the coated and bare NPs by Geobacter sulfurreducens was the same, which shows that the PAA coating does not significantly reduce NP Fe(III) bioavailability. Our results demonstrate that much improved transport of iron oxide NP can be achieved in saturated aquifer sediments by introducing negatively charged polyelectrolytes and optimizing polymer concentrations, and furthermore, these coated NPs retain their bioavailability that is needed for applications in bio-environmental remediation.

  10. Poly(vinyl alcohol)/poly(acrylic acid) hydrogel coatings for improving electrode-neural tissue interface.

    PubMed

    Lu, Yi; Wang, Dingfang; Li, Tao; Zhao, Xueqing; Cao, Yuliang; Yang, Hanxi; Duan, Yanwen Y

    2009-09-01

    A major problem which hinders the applications of neural prostheses is the inconsistent performance caused by tissue responses during long-term implantation. The study investigated a new approach for improving the electrode-neural tissue interface. Hydrogel poly(vinyl alcohol)/poly(acrylic acid) interpenetrating polymer networks (PVA/PAA IPNs) were synthesized and tailored as coatings for poly(dimethylsiloxane) (PDMS) based neural electrodes with the aid of plasma pretreatment. Changes in the electrochemical impedance and maximum charge injection (Q(inj)) limits of the coated iridium oxide microelectrodes were negligible. Protein adsorption on PDMS was reduced by approximately 85% after coating. In the presence of nerve growth factor (NGF), neurite extension of rat pheochromocytoma (PC12) cells was clearly greater on PVA/PAA IPN films than on PDMS substrates. Furthermore, the tissue responses of PDMS implants coated with PVA/PAA IPN films were studied by 6-week implantation in the cortex of rats, which found that the glial fibrillary acidic protein (GFAP) immunoreactivity in animals (n=8) receiving coated implants was significantly lower (p<0.05) compared to that of uncoated implants (n=7) along the entire distance of 150 microm from the outer skirt to the implant interface. The coated film remained on the surface of the explanted implants, confirmed by scanning electron microscopy (SEM). All of these suggest the hydrogel coating is feasible and favorable to neural electrode applications.

  11. A new approach for the immobilization of poly(acrylic) acid as a chemically reactive cross-linker on the surface of poly(lactic) acid-based biomaterials.

    PubMed

    Stankevich, Ksenia S; Danilenko, Nadezhda V; Gadirov, Ruslan M; Goreninskii, Semen I; Tverdokhlebov, Sergei I; Filimonov, Victor D

    2017-02-01

    A new approach for the immobilization of poly(acrylic) acid (PAA) as a chemically reactive cross-linker on the surface of poly(lactic) acid-based (PLA) biomaterials is described. The proposed technique includes non-covalent attachment of a PAA layer to the surface of PLA-based biomaterial via biomaterial surface treatment with solvent/non-solvent mixture followed by the entrapment of PAA from its solution. Surface morphology and wettability of the obtained PLA-PAA composite materials were investigated by AFM and the sitting drop method respectively. The amount of the carboxyl groups on the composites surface was determined by using the fluorescent compounds (2-(5-aminobenzo[d]oxazol-2-yl)phenol (ABO) and its acyl derivative N-(2-(2-hydroxyphenyl)benzo[d]oxazol-5-yl)acetamide (AcABO)). It was shown that it is possible to obtain PLA-PAA composites with various surface relief and tunable wettability (57°, 62° and 66°). The capacity of the created PAA layer could be varied from 1.5nmol/cm(2) to 0.1μmol/cm(2) depending on the modification conditions. Additionally, using bovine serum albumin (BSA) it was demonstrated that such composites could be modified with proteins with high binding density (around 0.18nmol/cm(2)). Obtained fluoro-labeled PLA-PAA materials, as well as PLA-PAA composites themselves, are valuable since they can be used for biodegradable polymer implants tracking in living systems and as drug delivery systems.

  12. 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

  13. 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

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

    PubMed

    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

    2015-10-01

    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.

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. Interactions of sodium montmorillonite with poly(acrylic acid).

    PubMed

    Tran, Nguyen H; Dennis, Gary R; Milev, Adriyan S; Kannangara, G S Kamali; Wilson, Michael A; Lamb, Robert N

    2005-10-15

    The chemical-structural modifications of the natural clay sodium montmorillonite during interaction with poly(acrylic acid) were studied mainly by X-ray photoemission spectroscopy. Samples of modified montmorillonite were prepared from the reaction of sodium montmorillonite ( approximately 0.5 g) and an aqueous solution of poly(acrylic acid) (pH approximately 1.8, 50 g) at varying temperatures. X-ray diffraction indicated that the montmorillonite interlayer space ( approximately 13 A), formed by regular stacking of the silicate layers (dimension approximately 1x1000 nm), expanded to approximately 16 A as the reaction was carried out at room temperature and at 30 degrees C. At 60 degrees C, the interlayer space further expanded to approximately 20 A. The results of X-ray photoemission spectroscopy indicated that poly(acrylic acid) molecules exchange sodium ions on the surface of the silicate layers. These combined results allowed development of a reaction model that explains the dependency of the interlayer expansion with temperature. Information concerning the surface chemical reactions and systematic increases in the interlayer distances is particularly useful if montmorillonite and poly(acrylic acid) are to be used for formation of nanocomposite materials.

  11. Acrylic acid and electric power cogeneration in an SOFC reactor.

    PubMed

    Ji, Baofeng; Wang, Jibo; Chu, Wenling; Yang, Weishen; Lin, Liwu

    2009-04-21

    A highly efficient catalyst, MoV(0.3)Te(0.17)Nb(0.12)O, used for acrylic acid (AA) production from propane, was used as an anodic catalyst in an SOFC reactor, from which AA and electric power were cogenerated at 400-450 degrees C.

  12. Evaluation of poly(acrylic acid-co-ethylhexyl acrylate) films for mucoadhesive transbuccal drug delivery: factors affecting the force of mucoadhesion.

    PubMed

    Shojaei, A H; Paulson, J; Honary, S

    2000-07-03

    Based on the premise that similar surface properties between the adhesive and the substrate would yield a strong adhesive bond, copolymers of acrylic acid (AA) and 2-ethylhexyl acrylate (EHA), P(AA-co-EHA), were designed and synthesized for buccal mucoadhesion. A series of linear copolymers with varying feed ratios of the two monomers (AA and EHA) were synthesized through free radical copolymerization at 69+/-0.5 degrees C using azobis(isobutyronitrile) (AIBN) as initiator. The reactions were carried out in THF under nitrogen for 24 h. The glass transition temperatures, T(g), of the copolymers were determined using DSC. The adhesion studies were conducted to determine the effects of copolymer composition, contact time between the substrate and the adhesive, and crosshead speed on mucoadhesive performance of the copolymer films using a computer interfaced Instron material testing system. The glass transition temperature of the copolymers decreased with increasing EHA content. Wet glass surface as substrate was shown not to be a good substrate model for adhesion determination studies. The copolymer composed of 46:54 mol.% AA:EHA (an almost 1:1 ratio in the repeat units) yielded the highest mucoadhesive force in contact with porcine buccal mucosa which was significantly greater (P<0.05) than that of poly(acrylic acid) (PAA) (used as positive control). The mucoadhesive force for all copolymers studied was significantly (P<0.05) greater than that of the negative control (backing material without copolymer film) except for the EHA homopolymer. Crosshead speed increased mucoadhesive force linearly and had a more pronounced effect on the mucoadhesive performance than time of contact between the adhesive and the substrate.

  13. 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).

  14. [Antiparasitic effects of peracetic acid (PAA) against infective stages (theronts) of white spot disease, Ichthyophthirius multifiliis in vitro].

    PubMed

    Meinelt, T; Staaks, J; Staaks, G; Stüber, A; Bräunig, I

    2007-10-01

    White spot disease, caused by the protozoan parasite Ichthyophthirius multifiliis (I. multifiliis), invades nearly all fresh water fish species and causes huge economic losses. In Germany no protocide substance is legal for the treatment of I. multifilis. As an alternative substance the peracetic acid (PAA) was tested to treat the free invasive stage (theront) of the parasite. PAA concentrations of 0.3 ppm were able to kill all theronts in 120 min in our investigations. As a result of these investigations we recommend an interval-application of 0.3 to 0.5 ppm PAA for 30 to 150 min. This application should be prolonged for two life cycles of the parasite. Biotic parameters as e. g. fish species, and age as well as abiotic parameters as e. g. temperature, pH and organic load of the water could possibly influence the efficiency of the PAA application and should therefore be taken into account while picking the dosage and length of the PAA exposure.

  15. 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...

  16. Poly(Vinyl Alcohol)/Poly(Acrylic Acid) Hydrogel in a dc Electric Field: Swelling, Shape Change, and Actuation Characteristics

    PubMed Central

    2014-01-01

    Poly(vinyl alcohol) (PVA)/Poly(acrylic acid) (PAA) hydrogel can be utilized as a biomimetic actuator and coating material for tissue-implant interface, when employing an electrical stimulus. The swelling, shape change, and actuation characteristics of PVA/PAA hydrogel in a range of dc electrical fields were determined to find the optimal electric field for the hydrogel application as biomimetic actuator and coating materials. The hydrogel samples were prepared by dissolving PVA and PAA in deionized water at 4 wt% and mixed together at 1:1 ratio. Two custom made experimental setups were fabricated; one used for the measurement of swelling ratio of the hydrogels; and the other used for the shape changes or actuation characteristics of the hydrogels. Swelling experiments show increased swelling ratios of the hydrogel due to 10 V, 20 V, and 30 V electric fields. The rate of increment of the swelling ratio of hydrogel samples under 10V was higher compare to those samples under 20 V and 30 V. The width and height changes of rectangular shapes and maximum deflection along the length of hydrogel sample due to a range of electric fields (0-30V) were measured using an optical microscope. Incremental shape change up to a specific threshold value (around 10V) was observed due to electric stimulus. Electrostatic actuation pressure of hydrogel samples under 10V was higher compare to those samples under 20 V and 30 V. These results suggested that optimal performance of PVA/PAA hydrogel can be achieved around 10V. PMID:25478321

  17. The transport of phenylacetic acid across the peroxisomal membrane is mediated by the PaaT protein in Penicillium chrysogenum.

    PubMed

    Fernández-Aguado, Marta; Ullán, Ricardo V; Teijeira, Fernando; Rodríguez-Castro, Raquel; Martín, Juan F

    2013-04-01

    Penicillium chrysogenum, an industrial microorganism used worldwide for penicillin production, is an excellent model to study the biochemistry and the cell biology of enzymes involved in the synthesis of secondary metabolites. The well-known peroxisomal location of the last two steps of penicillin biosynthesis (phenylacetyl-CoA ligase and isopenicillin N acyltransferase) requires the import into the peroxisomes of the intermediate isopenicillin N and the precursors phenylacetic acid and coenzyme A. The mechanisms for the molecular transport of these precursors are still poorly understood. In this work, a search was made, in the genome of P. chrysogenum, in order to find a Major Facilitator Superfamily (MFS) membrane protein homologous to CefT of Acremonium chrysogenum, which is known to confer resistance to phenylacetic acid. The paaT gene was found to encode a MFS membrane protein containing 12 transmembrane spanners and one Pex19p-binding domain for Pex19-mediated targeting to peroxisomal membranes. RNA interference-mediated silencing of the paaT gene caused a clear reduction of benzylpenicillin secretion and increased the sensitivity of P. chrysogenum to the penicillin precursor phenylacetic acid. The opposite behavior was found when paaT was overexpressed from the glutamate dehydrogenase promoter that increases phenylacetic acid resistance and penicillin production. Localization studies by fluorescent laser scanning microscopy using PaaT-DsRed and EGFP-SKL fluorescent fusion proteins clearly showed that the protein was located in the peroxisomal membrane. The results suggested that PaaT is involved in penicillin production, most likely through the translocation of side-chain precursors (phenylacetic acid and phenoxyacetic acid) from the cytosol to the peroxisomal lumen across the peroxisomal membrane of P. chrysogenum.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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.

  4. 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

  5. pH-sensing properties of cascaded long- and short-period fiber grating with poly acrylic acid/poly allylamine hydrochloride thin-film overlays

    NASA Astrophysics Data System (ADS)

    Yang, Ying

    2014-11-01

    Based on coupled-mode theory and transfer matrix method, the mode coupling mechanism and the reflection spectral properties of coated cascaded long- and short-period gratings (CLBG) are discussed. The effects of the thin-film parameters (film refractive index and film thickness) on the reflection spectra of the coated CLBG are simulated. By using electrostatic self-assembly method, poly acrylic acid (PAA) and poly allylamine hydrochloride (PAH) multilayer molecular pH-sensitive thin-films are assembled on the surface of the partial corroded CLBG. When the CLBG coated with PAA/PAH films are used to sense pH values, the resonant wavelengths of the CLBG have almost no shift, whereas the resonance peak reflectivities change with pH values. In addition, the sensitivities of the resonance peak reflectivities responding to pH values are improved by an order of magnitude.

  6. Self-assembling linear and star shaped poly(ϵ-caprolactone)/poly[(meth)acrylic acid] block copolymers as carriers of indomethacin and quercetin.

    PubMed

    Bury, Katarzyna; Du Prez, Filip; Neugebauer, Dorota

    2013-11-01

    A amphiphilic linear AB, BAB, and star shaped (AB)3 block copolymers of poly(ϵ-caprolactone) (PCL)/poly(meth)acrylic acid (P(M)AA) are used for the preparation of nanoparticles and drug entrapment, where indomethacin and quercetin are employed as model drugs. Drug loading experiments with the nanoparticles based on PAA block copolymers demonstrate a higher efficiency for the star structure, whereas the PMAA star copolymer presents the lowest entrapment ability. The release properties are studied at room temperature and 37 °C in phosphate buffer solutions with pH equal to 5 and 7.4. The kinetic profiles show a strong relation to the copolymer's topology, indicating the lowest release rates from the star based superstructures, while the PMAA particles are less stable than those containing PAA segment(s).

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-12-01

    In this study, multifunctional poly(acrylic acid) modified lanthanide-doped GdVO4 nanocomposites [PAA@GdVO4: Ln3+ (Ln = Yb/Er, Yb/Ho, Yb/Tm)] were constructed by filling PAA hydrogel into GdVO4 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 T1 contrast agents for magnetic resonance imaging (MRI) owing to the existence of Gd3+ ions on the surface of composites. Due to the nature of PAA, DOX-loaded PAA@GdVO4:Yb3+/Er3+ 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).

  9. Nanostructure of Poly(Acrylic Acid) Adsorption Layer on the Surface of Activated Carbon Obtained from Residue After Supercritical Extraction of Hops

    NASA Astrophysics Data System (ADS)

    Wiśniewska, M.; Nosal-Wiercińska, A.; Ostolska, I.; Sternik, D.; Nowicki, P.; Pietrzak, R.; Bazan-Wozniak, A.; Goncharuk, O.

    2017-01-01

    The nanostructure of poly(acrylic acid) (PAA) adsorption layer on the surface of mesoporous-activated carbon HPA obtained by physical activation of residue after supercritical extraction of hops was characterized. This characterization has been done based on the analysis of determination of adsorbed polymer amount, surface charge density, and zeta potential of solid particles (without and in the PAA presence). The SEM, thermogravimetric, FTIR, and MS techniques have allowed one to examine the solid surface morphology and specify different kinds of HPA surface groups. The effects of solution pH, as well as polymer molecular weight and concentration, were studied. The obtained results indicated that the highest adsorption on the activated carbon surface was exhibited by PAA with lower molecular weight (i.e., 2000 Da) at pH 3. Under such conditions, polymeric adsorption layer is composed of nanosized PAA coils (slightly negatively charged) which are densely packed on the positive surface of HPA. Additionally, the adsorption of polymeric macromolecules into solid pores is possible.

  10. Palladium Nanoparticles Embedded in a Layer-by-Layer Nanoreactor Built with Poly(Acrylic Acid) Using "Electro-Click Chemistry".

    PubMed

    Villalba, Matias; Bossi, Mariano; Pozo, Maria Del; Calvo, Ernesto J

    2016-07-12

    Palladium nanoparticles (Pd NPs) were formed by electrochemical reduction of Pd(NH3)4(3+) ions entrapped by ion exchange in poly(acrylic acid) (PAA) multilayer films grown by the Sharpless "click reaction." The alkyne (PAAalk) and azide (PAAaz) groups were covalently bound to the PAA, and the catalyzed buildup of the multilayer film was performed by electrochemical reduction of Cu(2+) to Cu(+). The size of the Pd NPs formed in Au/(PAAalk)3(PAAaz)2 multilayer films by the click reaction, that is, 50 nm, is larger than that of similar Pd NPs formed in electrostatically bound Au/(PAA)3(PAH)2 nanoreactors, that is, 6-9 nm, under similar conditions. A combination of electrochemical methods and electrochemical quartz crystal microbalance, polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS), ellipsometry, and scanning electron microscopy has been used to follow these processes. Cyclic voltammetry of the resulting Pd NPs in a 0.1 M H2SO4 solution at 0.1 V·s(-1) shows the PdO reduction peak at the same potential as that on the clean Pd surface unlike the NPs formed in electrostatically self-assembled Au/(PAA)3(PAH)2 nanoreactors with a 0.2 V shift in the cathodic direction most probably because of the strong adsorption of amino groups on the Pd NP surfaces.

  11. 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.

  12. Nanostructure of Poly(Acrylic Acid) Adsorption Layer on the Surface of Activated Carbon Obtained from Residue After Supercritical Extraction of Hops.

    PubMed

    Wiśniewska, M; Nosal-Wiercińska, A; Ostolska, I; Sternik, D; Nowicki, P; Pietrzak, R; Bazan-Wozniak, A; Goncharuk, O

    2017-12-01

    The nanostructure of poly(acrylic acid) (PAA) adsorption layer on the surface of mesoporous-activated carbon HPA obtained by physical activation of residue after supercritical extraction of hops was characterized. This characterization has been done based on the analysis of determination of adsorbed polymer amount, surface charge density, and zeta potential of solid particles (without and in the PAA presence). The SEM, thermogravimetric, FTIR, and MS techniques have allowed one to examine the solid surface morphology and specify different kinds of HPA surface groups. The effects of solution pH, as well as polymer molecular weight and concentration, were studied. The obtained results indicated that the highest adsorption on the activated carbon surface was exhibited by PAA with lower molecular weight (i.e., 2000 Da) at pH 3. Under such conditions, polymeric adsorption layer is composed of nanosized PAA coils (slightly negatively charged) which are densely packed on the positive surface of HPA. Additionally, the adsorption of polymeric macromolecules into solid pores is possible.

  13. 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.

  14. 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.

  15. Polydopamine-coated electrospun poly(vinyl alcohol)/poly(acrylic acid) membranes as efficient dye adsorbent with good recyclability.

    PubMed

    Yan, Jiajie; Huang, Yunpeng; Miao, Yue-E; Tjiu, Weng Weei; Liu, Tianxi

    2015-01-01

    Free-standing poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) membranes with polydopamine (PDA) coating were prepared based on the combination of electrospinning and self-polymerization of dopamine. This is a facile, mild, controllable, and low-energy consumption process without any rigorous restriction to reactive conditions. Benefiting from the high specific surface area of electrospun membranes and the abundant "adhesive" functional groups of polydopamine, the as-prepared membranes exhibit efficient adsorption performance towards methyl blue with the adsorption capacity reaching up to 1147.6 mg g(-1). Moreover, compared to other nanoparticle adsorbents, the as-prepared self-standing membrane is highly flexible, easy to operate and retrieve, and most importantly, easy to elute, and regenerate, which enable its potential applications in wastewater treatment.

  16. 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.

  17. Directed self-assembly of poly(styrene)-block-poly(acrylic acid) copolymers for sub-20nm pitch patterning

    NASA Astrophysics Data System (ADS)

    Cheng, Jing; Lawson, Richard A.; Yeh, Wei-Ming; Jarnagin, Nathan D.; Peters, Andrew; Tolbert, Laren M.; Henderson, Clifford L.

    2012-03-01

    Directed self-assembly (DSA) of block copolymers is a promising technology for extending the patterning capability of current lithographic exposure tools. For example, production of sub-40 nm pitch features using 193nm exposure technologies is conceivably possible using DSA methods without relying on time consuming, challenging, and expensive multiple patterning schemes. Significant recent work has focused on demonstration of the ability to produce large areas of regular grating structures with low numbers of defects using self-assembly of poly(styrene)-b-poly(methyl methacrylate) copolymers (PS-b-PMMA). While these recent results are promising and have shown the ability to print pitches approaching 20 nm using DSA, the ability to advance to even smaller pitches will be dependent upon the ability to develop new block copolymers with higher χ values and the associated alignment and block removal processes required to achieve successful DSA with these new materials. This paper reports on work focused on identifying higher χ block copolymers and their associated DSA processes for sub-20 nm pitch patterning. In this work, DSA using polystyrene-b-polyacid materials has been explored. Specifically, it is shown that poly(styrene)-b-poly(acrylic acid) copolymers (PS-b-PAA) is one promising material for achieving substantially smaller pitch patterns than those possible with PS-b-PMMA while still utilizing simple hydrocarbon polymers. In fact, it is anticipated that much of the learning that has been done with the PS-b-PMMA system, such as development of highly selective plasma etch block removal procedures, can be directly leveraged or transferred to the PS-b-PAA system. Acetone vapor annealing of PS-b-PAA (Mw=16,000 g/mol with 50:50 mole ratio of PS:PAA) and its self-assembly into a lamellar morphology is demonstrated to generate a pattern pitch size (L0) of 21 nm. The χ value for PS-b-PAA was estimated from fingerprint pattern pitch data to be approximately 0.18 which

  18. 78 FR 55644 - Styrene, Copolymers with Acrylic Acid and/or Methacrylic Acid; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... methacrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and/or hydroxyethyl acrylate; and its sodium... methacrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and/or hydroxyethyl acrylate; and its sodium... methacrylate, hydroxypropyl acrylate, hydroxyethyl methacrylate, and/or hydroxyethyl acrylate, and its...

  19. 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.

  20. 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.

  1. Human mesenchymal stem cell osteoblast differentiation, ECM deposition, and biomineralization on PAH/PAA polyelectrolyte multilayers.

    PubMed

    Pattabhi, Sudhakara Rao; Lehaf, Ali M; Schlenoff, Joseph B; Keller, Thomas C S

    2015-05-01

    Polyelectrolyte multilayer (PEMU) coatings built layer by layer with alternating pairs of polyelectrolytes can be tuned to improve cell interactions with surfaces and may be useful as biocompatible coatings to improve fixation between implants and tissues. Here, we show that human mesenchymal stromal cells (hMSCs) induced with bone differentiation medium (BDM) to become osteoblasts biomineralize crosslinked PEMUs built with the polycation poly(allylamine hydrochloride) (PAH) and the polyanion poly(acrylic acid) (PAA). Degrees of hMSC osteoblast differentiation and surface biomineralization on the smooth PAH-terminated PEMUs (PAH-PEMUs) and microstructured PAA-terminated PEMUs (PAA-PEMUs) reflect differences in cell-deposited extracellular matrix (ECM). BDM-induced hMSCs expressed higher levels of the early osteoblast differentiation marker alkaline phosphatase and collagen 1 (COL1) sooner on PAA-PEMUs than on PAH-PEMUs. Cells on both types of PEMUs proceeded to express the later stage osteoblast differentiation marker bone sialoprotein (BSP), but the BDM-induced cells organized a more amorphous Collagen I and denser BSP localization on PAA-PEMUs than on PAH-PEMUs. These ECM properties correlated with greater biomineralization on the PAA-PEMUs than on PAH-PEMUs. Together, these results confirm the suitability of PAH/PAA PEMUs as a substrate for hMSC osteogenesis and highlight the importance of substrate effects on ECM organization and BSP presentation on biomineralization.

  2. 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.

  3. 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

  4. Matrix tablets based on thiolated poly(acrylic acid): pH-dependent variation in disintegration and mucoadhesion.

    PubMed

    Guggi, Davide; Marschütz, Michaela K; Bernkop-Schnürch, Andreas

    2004-04-15

    This study examined the influence of the pH on the mucoadhesive and cohesive properties of polyarcylic acid (PAA) and thiolated PAA. The pH of PAA (molecular mass: 450 kDa) and of a corresponding PAA-cysteine conjugate was adjusted to 3, 4, 5, 6, 7 and 8. The amount of immobilised thiol groups and disulfide bonds was determined via Ellman's reagent. Tablets were compressed out of each pH-batch of both thiolated and unmodified PAA and the swelling behaviour, the disintegration time and the mucoadhesiveness were evaluated. The amount of thiol/disulfide groups per gram thiolated PAA of pH 3 and pH 8 was determined to be 332 +/- 94 micromol and 162 +/- 46 micromol, respectively. The thiolated PAA tablets displayed a minimum four-fold higher water uptake compared to unmodified PAA tablets. A faster and higher water uptake of both polymer types was observed above pH 5. Thiolated polymer tablets showed a 3-20-fold more prolonged disintegration time than unmodified PAA tablets. The cohesiveness of PAA-cysteine conjugate increased at higher pH, whereas the unmodified PAA behaved inversely. A 3-7-fold stronger mucoadhesiveness was observed for the PAA-cysteine conjugate tablets compared to unmodified PAA tablets. For both thiolated and unmodified polymer the mucoadhesiveness was 2-4-fold enhanced below pH 5. The difference in mucoadhesion between the two polymer types was most pronounced at these lower pH values. In this study substantial information regarding the pH-dependence of mucoadhesion and cohesion of unmodified polyacrylates and of thiolated polyacrylates is provided, representing helpful basic information for an ameliorated deployment of these polymers.

  5. pH-responsive drug delivery system based on luminescent CaF(2):Ce(3+)/Tb(3+)-poly(acrylic acid) hybrid microspheres.

    PubMed

    Dai, Yunlu; Zhang, Cuimiao; Cheng, Ziyong; Ma, Ping'an; Li, Chunxia; Kang, Xiaojiao; Yang, Dongmei; Lin, Jun

    2012-03-01

    In this study, we design a controlled release system based on CaF(2):Ce(3+)/Tb(3+)-poly(acrylic acid) (PAA) composite microspheres, which were fabricated by filling the pH-responsive PAA inside CaF(2):Ce(3+)/Tb(3+) hollow spheres via photopolymerization route. The CaF(2):Ce(3+)/Tb(3+) hollow spheres prepared by hydrothermal route possess mesoporous structure and show strong green fluorescence from Tb(3+) under UV excitation. Doxorubicin hydrochloride (DOX), a widely used anti-cancer drug, was used as a model drug to evaluate the loading and controlled release behaviors of the composite microspheres due to the good biocompatibility of the samples using MTT assay. The composite carriers provide a strongly pH-dependent drug release behavior owing to the intrinsic property of PAA and its interactions with DOX. The endocytosis process of drug-loaded microspheres was observed using confocal laser scanning microscopy (CLSM) and the in vitro cytotoxic effect against SKOV3 ovarian cancer cells of the DOX-loaded carriers was investigated. In addition, the extent of drug release could be monitored by the altering of photoluminescence (PL) intensity of CaF(2):Ce(3+)/Tb(3+). Considering the good biocompatibility, high drug loading content and pH-dependent drug release of the materials, these hybrid luminescent microspheres have potential applications in drug controlled release and disease therapy.

  6. “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

  7. Radiation induced deposition of copper nanoparticles inside the nanochannels of poly(acrylic acid)-grafted poly(ethylene terephthalate) track-etched membranes

    NASA Astrophysics Data System (ADS)

    Korolkov, Ilya V.; Güven, Olgun; Mashentseva, Anastassiya A.; Atıcı, Ayse Bakar; Gorin, Yevgeniy G.; Zdorovets, Maxim V.; Taltenov, Abzal A.

    2017-01-01

    Poly(ethylene terephthalate) PET, track-etched membranes (TeMs) with 400 nm average pore size were UV-grafted with poly(acrylic acid) (PAA) after oxidation of inner surfaces by H2O2/UV system. Carboxylate groups of grafted PAA chains were easily complexed with Cu2+ ions in aqueous solutions. These ions were converted into metallic copper nanoparticles (NPs) by radiation-induced reduction of copper ions in aqueous-alcohol solution by gamma rays in the dose range of 46-250 kGy. Copper ions chelating with -COOH groups of PAA chains grafted on PET TeMs form polymer-metal ion complex that prevent the formation of agglomerates during reduction of copper ions to metallic nanoparticles. The detailed analysis by X-Ray diffraction technique (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) confirmed the deposition of copper nanoparticles with the average size of 70 nm on the inner surface of nanochannels of PET TeMs. Samples were also investigated by FTIR, ESR spectroscopies to follow copper ion reduction.

  8. "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.

  9. 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

  10. Radiation grafting of acrylic acid onto partially deacetylated chitin for metal ion adsorbent

    NASA Astrophysics Data System (ADS)

    Hien, Nguyen Quoc; Van Phu, Dang; Duy, Nguyen Ngoc; Huy, Ha Thuc

    2005-07-01

    Radiation processing technology is proved to be a useful tool for modification of polymer material including grafting of monomer onto polymer. In this study, partially deacetylated chitin (PD-chitin) was prepared by soaking chitin in NaOH solution with various concentrations from 10% to 50% (w/w) at room temperature for four days. The degree of deacetylation (DD%) of chitin samples was measured by IR spectroscopy method. Radiation grafting of acrylic acid (AAc) onto PD-chitin was carried out by immerging PD-chitin in AAc solution (5-20%v/v) for swelling two days. The swelled PD-chitin sample was filtered and irradiated with Co-60 radiation at dose of 4.8 kGy for grafting. The resulting product, so called PD-chitin-g-PAA was changed to sodium form, PD-chitin-g-PANa by treating with NaOH 1 N and used as metal ion adsorbent. The adsorption capacities of studied chitin samples for metal ion typically for Cu2+ was determined using atomic absorption spectrophotometer. The results showed that the adsorption capacities for Cu2+ were as the following order: chitin < PD-chitin < PD-chitin-g-PANa < chitosan (DD76%). In addition, equilibrium isotherms were well fitted by Langmuir equation with the constants KL = 15.5 and 19.4 (mg/g); b = 0.02 and 0.04 (L/mg) for PD-chitin and PD-chitin-g-PANa, respectively. The obtained product, PD-chitin-g-PANa can be produced on large scale with competitive cost and used as metal ion adsorbent for water purification as well as for other purposes such as for sorption of dyes and for immobilization of bioactive substances.

  11. 75 FR 770 - Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2-methyl-2-[(1-oxo-2-propenyl)amino...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-06

    ... AGENCY 40 CFR Part 180 Acrylic acid-benzyl methacrylate-1-propanesulfonic acid, 2- methyl-2... residues of acrylic acid-benzyl methacrylate-1- propanesulfonic acid, 2-methyl-2- -, monosodium salt... to establish a maximum permissible level for residues of acrylic acid-benzyl...

  12. Stability effect of cholesterol-poly(acrylic acid) in a stimuli-responsive polymer-liposome complex obtained from soybean lecithin for controlled drug delivery.

    PubMed

    Simões, M G; Alves, P; Carvalheiro, Manuela; Simões, P N

    2017-04-01

    The development of polymer-liposome complexes (PLCs), in particular for biomedical applications, has grown significantly in the last decades. The importance of these studies comes from the emerging need in finding intelligent controlled release systems, more predictable, effective and selective, for applications in several areas, such as treatment and/or diagnosis of cancer, neurological, dermatological, ophthalmic and orthopedic diseases, gene therapy, cosmetic treatments, and food engineering. This work reports the development and characterization of a pH sensitive system for controlled release based on PLCs. The selected hydrophilic polymer was poly(acrylic acid) (PAA) synthesized by atom transfer radical polymerization (ATRP) with a cholesterol (CHO) end-group to improve the anchoring of the polymer into the lipid bilayer. The polymer was incorporated into liposomes formulated from soybean lecithin and stearylamine, with different stearylamine/phospholipid and polymer/phospholipid ratios (5, 10 and 20%). The developed PLCs were characterized in terms of particle size, polydispersity, zeta potential, release profiles, and encapsulation efficiency. Cell viability studies were performed to assess the cytotoxic potential of PLCs. The results showed that the liposomal formulation with 5% of stearylamine and 10% of polymer positively contribute to the stabilization of the complexes. Afterwards, the carboxylic acid groups of the polymer present at the surface of the liposomes were crosslinked and the same parameters analyzed. The crosslinked complexes showed to be more stable at physiologic conditions. In addition, the release profiles at different pHs (2-12) revealed that the obtained complexes released all their content at acidic conditions. In summary, the main accomplishments of this work are: (i) innovative synthesis of cholesterol-poly(acrylic acid) (CHO-PAA) by ATRP; (ii) stabilization of the liposomal formulation by incorporation of stearylamine and CHO-PAA

  13. 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).

  14. Emulsion polymerization of polystyrene-co-acrylic acid with Cu2O incorporation

    NASA Astrophysics Data System (ADS)

    Fahmiati, Sri; Harmami, Sri Budi; Meliana, Yenny; Haryono, Agus

    2017-01-01

    In this research, poly(styrene-co-acrylic acid-Cu) was prepared via emulsion polymerization.Cu contents were varied as 10%, 15% and 20% and mol ratio of styrene to acrylic acid as 1:1 and 2:1. Structure and surface of poly(styrene-co-acrylic acid-Cu) were characterized by FTIR (Fourier Transformed Infra Red), NMR (Nuclear Magnetic Resonance), and SEM/EDX (Scanning Electron Microcope/ Energy Dispersive X-Ray) spectroscopy. The NMR spectra showed that the polymer was formed, however FTIR spectra showed that there were still unreacted monomers. SEM-EDX confirmed that copper (Cu) was dispersed uniformly on poly(styrene-co-acrylic acid-Cu) matrix.

  15. 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.

  16. 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.

  17. 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.

  18. 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).

  19. Fast removal of copper ions from aqueous solution by chitosan-g-poly(acrylic acid)/attapulgite composites.

    PubMed

    Wang, Xiaohuan; Zheng, Yian; Wang, Aiqin

    2009-09-15

    Novel chitosan-g-poly(acrylic acid)/attapulgite (CTS-g-PAA/APT) composites were applied as adsorbents for the removal of Cu(II) from aqueous solution. The effects of the initial pH value (pH(0)) of Cu(II) solution, contact time (t), APT content (wt%) and the initial concentration of Cu(II) solution (C(0)) on the adsorption capacity of the composites were investigated. Results from kinetic experimental data showed that the Cu(II) adsorption rate on the composites with 10, 20 and 30 wt% APT was fast and more than 90% of the maximum adsorption capacity for Cu(II) occurred within the initial 15 min. The adsorption kinetics was better described by the pseudo-second order equation, and their adsorption isotherms were better fitted for the Langmuir equation. The results of the five-time consecutive adsorption-desorption studies showed that the composites had high adsorption and desorption efficiencies, which implies that the composites may be used as quite effective adsorbents for the removal of Cu(II) from aqueous solution.

  20. Focal point analysis of torsional isomers of acrylic acid

    NASA Astrophysics Data System (ADS)

    Alev Çiftçioğlu, Gökçen; Trindle, Carl; Yavuz, Ilhan

    2010-10-01

    The thermochemistry of acrylic acid has presented challenges owing to its high reactivity, tendency to dimerize in the gas phase, and the existence of two very nearly equal energy conformational isomers. Well-tested thermochemical schemes including G2, G3, G4, and CBS-QB3 agree in the prediction that the s-cis syn structure is the most stable of the torsional isomers, with the s-cis anti form lying 3 kJ mol-1 or less higher in energy. Microwave spectra suggest a value of 0.63 kJ mol-1. The energy barrier between these forms is in the neighbourhood of 25 kJ mol-1 according to a MP2/cc-pVDZ calculation. We present estimates of the relative energies of all four torsional isomers and the rotational barrier based on a variant of the Focal Point Analysis developed by Császár and co-workers. These calculations, extending to the CCSD(T)/cc-pV5Z level, predict that the s-cis anti torsional isomer is the most stable form, in contrast to prior estimates. The s-cis syn form lies about 2.9 kJ mol-1 higher, while the s-trans syn and anti forms lie at about 21.7 and 23.3 kJ mol-1, respectively. We estimate the rotational barrier between the s-cis trans and s-cis anti structures to be about 23.9 kJ mol-1. Error ranges derived from the fit to extrapolation forms suggest that our estimates have an uncertainty of about 0.1 kJ mol-1.

  1. Supercritical water oxidation of acrylic acid production wastewater.

    PubMed

    Gong, Y M; Wang, S Z; Tang, X Y; Xu, D H; Ma, H H

    2014-01-01

    Supercritical water oxidation (SCWO) of wastewater from an acrylic acid manufacturing plant has been studied on a continuous flow experimental system, whose reactor was made of Hastelloy C-276. Experimental conditions included a reaction temperature (T) ranging from 673 to 773K, a residence time (t) ranging from 72.7 to 339s, a constant pressure (P) of 25 MPa and a fixed oxidation coefficient (alpha) of 2.0. Experimental results indicated that reaction temperature and residence time had significant influences on the oxidation reaction, and increasing the two operation parameters could improve both degradation of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). The COD removal efficiency could reach up to 98.73% at 25 MPa, 773 K and 180.1 s, whereas the destruction efficiency of NH3-N was only 43.71%. We further carried out a kinetic analysis considering the induction period through free radical chain mechanism. It confirms that the power-law rate equation for COD removal was 345 exp(-52200/RT)[COD]1.98[O2]0.17 and for NH3-N removal was 500 exp(-64492.19/RT)[NH3-N]1.87 [O2]0.03. Moreover, the induction time formulations for COD and NH3-N were suspected to be exp(38250/RT)/173 and exp(55690/RT)/15231, respectively. Correspondingly, induction time changed from 2.22 to 5.38 s for COD and 0.38 to 1.38 s for NH3-N. Owing to the catalysis of reactor inner wall surface, more than 97% COD removal was achieved in all samples.

  2. 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.

  3. 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.

  4. Polyelectrolyte conformational transition in aqueous solvent mixture influenced by hydrophobic interactions and hydrogen bonding effects: PAA-water-ethanol.

    PubMed

    Sappidi, Praveenkumar; Natarajan, Upendra

    2016-03-01

    Molecular dynamics simulations of poly(acrylic acid) PAA chain in water-ethanol mixture were performed for un-ionized and ionized cases at different degree-of-ionization 0%, 80% and 100% of PAA chain by Na(+) counter-ions and co-solvent (ethanol) concentration in the range 0-90vol% ethanol. Aspects of structure and dynamics were investigated via atom pair correlation functions, number and relaxation of hydrogen bonds, nearest-neighbor coordination numbers, and dihedral angle distribution function for back-bone and side-groups of the chain. With increase in ethanol concentration, chain swelling is observed for un-ionized chain (f=0) and on the contrary chain shrinkage is observed for partially and fully ionized cases (i.e., f=0.8 and 1). For un-ionized PAA, with increase in ethanol fraction ϕeth the number of PAA-ethanol hydrogen bonds increases while PAA-water decreases. Increase in ϕeth leads to PAA chain expansion for un-ionized case and chain shrinkage for ionized case, in agreement with experimental observations on this system. For ionized-PAA case, chain shrinkage is found to be influenced by intermolecular hydrogen bonding with water as well as ethanol. The localization of ethanol molecules near the un-ionized PAA backbone at higher levels of ethanol is facilitated by a displacement of water molecules indicating presence of specific ethanol hydration shell, as confirmed by results of the RDF curves and coordination number calculations. This behavior, controlled by hydrogen bonding provides a significant contribution to such a conformational transition behavior of the polyelectrolyte chain. The interactions between counter-ions and charges on the PAA chain also influence chain collapse. The underlying origins of polyelectrolyte chain collapse in water-alcohol mixtures are brought out for the first time via explicit MD simulations by this study.

  5. 40 CFR 721.10339 - Adipic acid, substituted propane, alkyldiol, acrylate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Adipic acid, substituted propane... Significant New Uses for Specific Chemical Substances § 721.10339 Adipic acid, substituted propane, alkyldiol... substance identified generically as adipic acid, substituted propane, alkyldiol, acrylate (PMN P-04-113)...

  6. 40 CFR 721.10339 - Adipic acid, substituted propane, alkyldiol, acrylate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Adipic acid, substituted propane... Significant New Uses for Specific Chemical Substances § 721.10339 Adipic acid, substituted propane, alkyldiol... substance identified generically as adipic acid, substituted propane, alkyldiol, acrylate (PMN P-04-113)...

  7. 40 CFR 721.10339 - Adipic acid, substituted propane, alkyldiol, acrylate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Adipic acid, substituted propane... Significant New Uses for Specific Chemical Substances § 721.10339 Adipic acid, substituted propane, alkyldiol... substance identified generically as adipic acid, substituted propane, alkyldiol, acrylate (PMN P-04-113)...

  8. Pervaporation separation of binary organic-aqueous liquid mixtures using crosslinked PVA membranes. I. Characterization of the reaction between PVA and PAA

    SciTech Connect

    Jiwon Rhim; Kewho Lee . Membranes and Separation Lab.); Minyoung Sohn; Hyeokjong Joo . Dept. of Polymer Science and Engineering)

    1993-10-20

    For the purpose of the water-selective membrane material development for pervaporation separation, poly(vinyl alcohol) (PVA) was crosslinked with a low molecular weight of poly(acrylic acid) (PAA). The crosslinking reactions between PVA and PAA were characterized through IR spectroscopy, differential scanning calorimetry (DSC), and tensile tests when varying the reaction conditions, that is, time, temperature, amounts of cross-linking agents, PAA. It was found that the crosslinking reaction was fast: in other words, that the reaction mainly occurred at the initial step of each reaction condition. The best reaction conditions for preparing the crosslinked PVA membranes were found to be: reaction time not over 1 h, reaction temperature in the range of 150-180 C. PAA contents of 15-20 wt% were found satisfactory with respect to the application areas.

  9. Rapid removal of Pb(II) from aqueous solution by chitosan-g-poly(acrylic acid)/attapulgite/ sodium humate composite hydrogels.

    PubMed

    Zhang, Junping; Jin, Yeling; Wang, Aiqin

    2011-04-01

    A series of novel granular chitosan-g-poly(acrylic acid)/attapulgite/sodium humate (CTS-g-PAA/APT/SH) composite hydrogels were successfully prepared by one-step free radical graft polymerization and applied as adsorbents for the removal of Pb(II) from aqueous solution. The effects of adsorbent composition (including the contents of APT, SH and CTS) on adsorption capacity and adsorption rate were investigated in detail. Results from kinetic experiments showed that the rate of Pb(II) adsorption on the composite hydrogels was quite fast, that more than 90% of the equilibrium adsorption capacity occurs within two minutes and that the adsorption equilibrium could be achieved within 10 minutes. The adsorption kinetics fit well with the pseudo-second order equation. The introduced SH is helpful for both adsorption capacity and adsorption rate. The -COOH and -COO of PAA, -NH2 of CTS, Ph-O and -COO- of SH, as well as cation exchange and Si-OH of APT, participate in adsorption of Pb(II). The synergistic effect of these groups is responsible for the high adsorption capacity and rate.

  10. Improved In Vitro and In Vivo Biocompatibility of Graphene Oxide through Surface Modification: Poly(Acrylic Acid)-Functionalization is Superior to PEGylation.

    PubMed

    Xu, Ming; Zhu, Jianqiang; Wang, Fanfan; Xiong, Yunjing; Wu, Yakun; Wang, Qiuquan; Weng, Jian; Zhang, Zhihong; Chen, Wei; Liu, Sijin

    2016-03-22

    The unique physicochemical properties of two-dimensional (2D) graphene oxide (GO) could greatly benefit the biomedical field; however, recent research demonstrated that GO could induce in vitro and in vivo toxicity. We determined the mechanism of GO induced toxicity, and our in vitro experiments revealed that pristine GO could impair cell membrane integrity and functions including regulation of membrane- and cytoskeleton-associated genes, membrane permeability, fluidity and ion channels. Furthermore, GO induced platelet depletion, pro-inflammatory response and pathological changes of lung and liver in mice. To improve the biocompatibility of pristine GO, we prepared a series of GO derivatives including aminated GO (GO-NH2), poly(acrylamide)-functionalized GO (GO-PAM), poly(acrylic acid)-functionalized GO (GO-PAA) and poly(ethylene glycol)-functionalized GO (GO-PEG), and compared their toxicity with pristine GO in vitro and in vivo. Among these GO derivatives, GO-PEG and GO-PAA induced less toxicity than pristine GO, and GO-PAA was the most biocompatible one in vitro and in vivo. The differences in biocompatibility were due to the differential compositions of protein corona, especially immunoglobulin G (IgG), formed on their surfaces that determine their cell membrane interaction and cellular uptake, the extent of platelet depletion in blood, thrombus formation under short-term exposure and the pro-inflammatory effects under long-term exposure. Overall, our combined data delineated the key molecular mechanisms underlying the in vivo and in vitro biological behaviors and toxicity of pristine GO, and identified a safer GO derivative that could be used for future applications.

  11. Synthesis of radiation crosslinked poly(acrylic acid) in the presence of phenyltriethoxysilane

    NASA Astrophysics Data System (ADS)

    Hassan, Safia; Yasin, Tariq

    2014-04-01

    Acrylic acid based superabsorbent hydrogel was prepared using phenyltriethoxysilane (PTES) as polyfunctional monomer. Different amounts of PTES were incorporated in acrylic acid and irradiated at different doses upto maximum of 30 kGy. The crosslinked acrylic acid showed hydrogel properties and its swelling kinetics, gel fraction and equilibrium degree of swelling (EDS) were studied. It was found that the increased PTES concentration decreased the EDS of the hydrogels. Infrared spectroscopy confirmed the crosslinking reaction between the feed components and the existence of siloxane bond. Thermogravimetric analysis showed an increase in the stability of the hydrogels having high PTES content. The swelling of the hydrogel was affected by pH, ionic strength and temperature. These hydrogels showed low swelling in acidic and basic pH range and high swelling around neutral pH. This switchable pH response of these hydrogels can be exploited in environmental and biomedical applications.

  12. Surface modification of cellulosic substrates via atmospheric pressure plasma polymerization of acrylic acid: Structure and properties

    NASA Astrophysics Data System (ADS)

    Garcia-Torres, Jose; Sylla, Dioulde; Molina, Laura; Crespo, Eulalia; Mota, Jordi; Bautista, Llorenç

    2014-06-01

    Surface chemical modification of cellulose-based substrates has been carried out by atmospheric pressure plasma enhanced chemical vapor deposition (AP-PECVD) of acrylic acid. The structure/properties relationship of the samples was studied as a function of the plasma experimental conditions. Acrylic acid monomer/helium ratio and treatment speed clearly influences the wettability properties of the paper substrate: advancing contact angle values were reduced to the half if compare to non-treated paper. Surface morphology of the films did not greatly vary at short polymerization times but fibers were covered by a poly(acrylic acid) film at longer times. FTIR and XPS techniques allowed detecting the retention of carboxylic acid groups/moieties. The possibility to quickly design architectures with tunable carboxylic functions by modifying the plasma processing parameters is shown.

  13. Mucin/poly(acrylic acid) interactions: a spectroscopic investigation of mucoadhesion.

    PubMed

    Patel, Minesh M; Smart, John D; Nevell, Thomas G; Ewen, Richard J; Eaton, Peter J; Tsibouklis, John

    2003-01-01

    Studies using infrared, (1)H and (13)C nuclear magnetic resonance, and X-ray photoelectron spectroscopies and differential scanning calorimetry support the hypothesis that hydrogen bonds, formed between the carboxylic acid functionality of the mucoadhesive material poly(acrylic acid) and the glycoprotein component of mucus, play a significant role in the process of mucoadhesion. There are fewer H-bonded interactions between the components than within the bulk of the pure mucoadhesive agent. The pH of the medium influences the structures of both the poly(acrylic acid) and the mucus, which, in turn, determine the nature and the extent of mucoadhesive interactions.

  14. 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.

  15. 76 FR 77709 - Butyl acrylate-methacrylic acid-styrene polymer; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-14

    ... AGENCY 40 CFR Part 180 Butyl acrylate-methacrylic acid-styrene polymer; Tolerance Exemption AGENCY... from the requirement of a tolerance for residues of 2-Propenoic acid, 2-methyl-, polymer with butyl 2...-styrene polymer when used as an inert ingredient in a pesticide chemical formulation....

  16. 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.

  17. Evaluation of Liquid-Liquid Extraction Process for Separating Acrylic Acid Produced From Renewable Sugars

    NASA Astrophysics Data System (ADS)

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

    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 univeral 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.

  18. 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.

  19. 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.

  20. 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.

  1. Synthesis and antibacterial properties of beta-diketone acrylate bioisosteres of pseudomonic acid A.

    PubMed

    Bennett, I; Broom, N J; Cassels, R; Elder, J S; Masson, N D; O'Hanlon, P J

    1999-07-05

    A series of beta-diketone acrylate bioisosteres 4 of pseudomonic acid A 1 have been synthesized and evaluated for their ability to inhibit bacterial isoleucyl-tRNA synthetase and act as antibacterial agents. A number of analogues have excellent antibacterial activity. Selected examples were shown to afford good blood levels and to be effective in a murine infection model.

  2. 40 CFR 721.10389 - Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10389 Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic). (a) Chemical substance and significant new...

  3. 40 CFR 721.10389 - Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10389 Styrene, copolymer with acrylic acid, salt with alkoxylated alkenylamine (generic). (a) Chemical substance and significant new...

  4. 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.

  5. Specific influence of univalent cations on the ionization of alumina-coated TiO2 particles and on the adsorption of poly(acrylic)acid.

    PubMed

    Malgat, Alexandre; Boisvert, Jean-Philippe; Daneault, Claude

    2004-01-15

    A surface counterion titration method was used to monitor the interaction of monovalents cations (Li(+), Na(+), TMA(+)) with the surface of alumina-coated TiO(2) particles in concentrated media at different pH and electrolyte concentrations. This method allows measuring separately the negative and positive contribution to the surface charge. It showed that Cl(-) and TMA(+) are indifferent ions, but Li(+) and Na(+) specifically adsorb on the non-ionized alumina surface sites. The binding sequence of cations is Li(+)>Na(+)>TMA(+) at all ionic strengths investigated and is consistent with the structure-making and structure-breaking model developed a few decades ago. Polyacrylic acid (PAA) previously neutralized with the corresponding hydroxide (LiOH, NaOH, TMAOH) has been adsorbed on the alumina surface at different pH. The polymer counterion has a significant influence on the polymer adsorption. The sequence of the surface coverage as a function of the polymer counterion follows the order Li-PAA > Na-PAA > TMA-PAA. The much higher surface coverage with Li-PAA and Na-PAA compared to TMA-PAA is explained by the specific adsorption of Li-PAA and Na-PAA on the nonionized alumina surface sites, the same way LiCl and NaCl do.

  6. 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.

  7. 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.

  8. Peroxyacetyl nitrate (PAN) and peroxyacetic acid (PAA) measurements by iodide chemical ionisation mass spectrometry: first analysis of results in the boreal forest and implications for the measurement of PAN fluxes

    NASA Astrophysics Data System (ADS)

    Phillips, G. J.; Pouvesle, N.; Thieser, J.; Schuster, G.; Axinte, R.; Fischer, H.; Williams, J.; Lelieveld, J.; Crowley, J. N.

    2013-02-01

    We describe measurements of peroxyacetyl nitrate (CH3C(O)O2NO2, PAN) and peroxyacetic acid (CH3C(O)OOH, PAA) in the Boreal forest using iodide chemical ionization mass spectrometry (ICIMS). The measurements were made during the Hyytiälä United Measurement of Photochemistry and Particles - Comprehensive Organic Particle and Environmental Chemistry (HUMPPA-COPEC-2010) measurement intensive. Mixing ratios of PAN and PAA were determined by measuring the acetate ion signal (CH3C(O)O-, m/z = 59) resulting from reaction of CH3C(O)O2 (from the thermal dissociation of PAN) or CH3C(O)OOH with iodide ions using alternatively heated and ambient temperature inlet lines. During some periods of high temperature (~ 30 °C) and low NOx (< 1 ppbv), PAA mixing ratios were similar to, or exceeded those of PAN and thus contributed a significant fraction of the total acetate signal. PAA is thus a potential interference for ICIMS measurements of PAN, and especially eddy covariance flux measurements in environments where the PAA flux is likely to be a significant proportion of the (short timescale) acetate ion variability. Within the range of mixing ratios of NOx measured during HUMPPA-COPEC, the modelled ratio of PAA-to-PAN was found to be sensitive to temperature (through the thermal decomposition rate of PAN) and the HO2 mixing ratio, thus providing some constraint to estimates of photochemical activity and oxidation rates in the Boreal environment.

  9. Peroxyacetyl nitrate (PAN) and peroxyacetic acid (PAA) measurements by iodide chemical ionisation mass spectrometry: first analysis of results in the boreal forest and implications for the measurement of PAN fluxes

    NASA Astrophysics Data System (ADS)

    Phillips, G. J.; Pouvesle, N.; Thieser, J.; Schuster, G.; Axinte, R.; Fischer, H.; Williams, J.; Lelieveld, J.; Crowley, J. N.

    2012-08-01

    We describe measurements of peroxyacetyl nitrate (CH3C(O)O2NO2, PAN) and peroxyacetic acid (CH3C(O)OOH, PAA) in the Boreal forest using iodide chemical ionization mass spectrometry (ICIMS). The measurements were made during the Hyytiälä United Measurement of Photochemistry and Particles - Comprehensive Organic Particle and Environmental Chemistry (HUMPPA-COPEC-2010) measurement intensive. Mixing ratios of PAN and PAA were determined by measuring the acetate ion signal (CH3C(O)O2-, m/z 59) resulting from reaction of CH3C(O)O2 (from the thermal dissociation of PAN) or CH3C(O)OOH with iodide ions using alternatively heated and ambient temperature inlet lines. During conditions of high temperature and low NOx, PAA mixing ratios were similar to, or exceeded those of PAN and thus contributed a significant fraction of the total acetate signal. PAA is thus a potential interference for ICIMS measurements of PAN, and especially eddy covariance flux measurements in environments where the PAA flux is likely to be a significant proportion of the short timescale acetate ion variability. Within the range of mixing ratios of NOx measured during HUMPPA-COPEC, the ratio of PAA-to-PAN was found to be sensitive to temperature (through the thermal decomposition rate of PAN) and the HO2 mixing ratio, thus providing some constraint to estimates of photochemical activity and oxidation rates in the Boreal environment.

  10. Optimization of acrylic acid grafting onto polypropylene using response surface methodology and its biodegradability

    NASA Astrophysics Data System (ADS)

    Mandal, Dev K.; Bhunia, Haripada; Bajpai, Pramod K.; Kushwaha, Jai P.; Chaudhari, Chandrasekhar V.; Dubey, Kumar A.; Varshney, Lalit

    2017-03-01

    Simultaneous radiation grafting was optimized to graft acrylic acid monomer on the polypropylene (PP) films to make them hydrophilic and enhance their biodegradability. Experiments were designed based on full factorial central composite design (response surface methodology) and influence of monomer concentration, radiation dose, inhibitor concentration, solvent concentration on degree of grafting was investigated. The extent of grafting was found to increase with increasing monomer concentration, inhibitor concentration and radiation dose. The targeted 35% grafting could be achieved at optimum condition viz. monomer concentration 12.09 wt%, radiation dose 12.40 kGy, inhibitor concentration 0.07 M and solvent concentration 0.12 M. The grafted PP films at different degrees of grafting were tested for tensile properties and characterized by swelling studies, fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). Successful grafting of acrylic acid onto polypropylene films was indicated by FTIR and confirmed quantitatively by determination of carboxylic groups on the film surface. Tensile strength of grafted PP films decreased with increase in degree of grafting. The crystallinity of the grafted PP films was lower than that of PP film as indicated by DSC studies. Grafting of acrylic acid increased the roughness on the surface of PP films indicated by SEM studies. The maximum biodegradability of the 34.55% grafted film was 5.5%.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. A density functional study on dielectric properties of acrylic acid grafted polypropylene.

    PubMed

    Ruuska, Henna; Arola, Eero; Kortelainen, Tommi; Rantala, Tapio T; Kannus, Kari; Valkealahti, Seppo

    2011-04-07

    Influence of acrylic acid grafting of isotactic polypropylene on the dielectric properties of the polymer is investigated using density functional theory (DFT) calculations, both in the molecular modeling and three-dimensional (3D) bulk periodic system frameworks. In our molecular modeling calculations, polarizability volume, and polarizability volume per mass which reflects the permittivity of the polymer, as well as the HOMO-LUMO gap, one of the important measures indicating the electrical breakdown voltage strength, were examined for oligomers with various chain lengths and carboxyl mixture ratios. When a polypropylene oligomer is grafted with carboxyl groups (cf. acrylic acid), our calculations show that the increase of the polarizability volume α' of the oligomer is proportional to the increase of its mass m, while the ratio α'/m decreases from the value of a pure polymer when increasing the mixture ratio. The decreasing ratio of α'/m under carboxyl grafting indicates that the material permittivity might also decrease if the mass density of the material remains constant. Furthermore, our calculations show that the HOMO-LUMO gap energy decreases by only about 15% in grafting, but this decrease seems to be independent on the mixture ratio of carboxyl. This indicates that by doping polymers with additives better dielectric properties can be tailored. Finally, using the first-principles molecular DFT results for polarizability volume per mass in connection with the classical Clausius-Mossotti relation, we have estimated static permittivity for acrylic acid grafted polypropylene, assuming the structural density keeping constant under grafting. The computed permittivity values are in a qualitative agreement with the recent experiments, showing increasing tendency of the permittivity as a function of the grafting composition. In order to validate our molecular DFT based approach, we have also carried out extensive three-dimensional bulk periodic first

  18. 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 ...

  19. Radiation-induced graft polymerization of acrylamide and acrylic acid onto polyethylene

    NASA Astrophysics Data System (ADS)

    Grushevskaya, L. N.; Aliev, R. E.; Kabanov, V. Ya.

    The radiation-induced grafting of acrylamide onto low-density polyethylene by the different methods and under different conditions was investigated: by the direct liquid phase method from this monomer solution in water (in neutral and acid media) and acetone, and by the pre-irradiation method from aqueous solutions as well as from its sublimated vapour. The molecular masses of polyacrylamide homopolymers were determined. The discussion and comparison of different methods of acrylamide grafting are performed. The relationship between rates of graft polymerization onto polyethylene and homopolymerization of acrylic acid in the presence of metal ions is considered.

  20. 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

  1. 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

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

    2011-10-01

    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 Li(2)SO(4) 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.

  2. 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.

  3. 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.

  4. Block ionomer complex micelles based on the self-assembly of poly(ethylene glycol)-block-poly(acrylic acid) and CdCl₂ for anti-tumor drug delivery.

    PubMed

    An, Liping; Wang, Yapei; Liu, Xiaomei; Ma, Ning; Du, Haiying; Jin, Minghua; Liu, Ying; Zhang, Long; Xu, Yanling; Huang, Peili; Sun, Zhiwei

    2011-01-01

    A novel block ionomer complex micelles as drug carrier is developed utilizing self-assemble of poly(ethylene glycol)-block-poly(acrylic acid) (PEG-b-PAA) and cadmium chloride. This micelles are characterized to be have good bio-compatibility, hydrophilicity, passive targeting and sustained slow release property which shows great potential for liver cancer therapy. Block ionomer complex micelles based on PEG-b-PAA and cadmium chloride can self-assemble in distilled water, and Cd(²+) agent is entrapped into the core stabilized by PEG shells. Results showed the block ionomer complex micelles to be spherically shaped. Cadmium was incorporated easily into the ionic core with remarkably high efficiency (34.25% weight (wt)/wt). The cadmium-loaded polymeric micelles exhibited sustained and slow release behavior of cadmium and a potent cytotoxicity against SMMC-7721 in vitro. This novel block ionomer complex micelles with cores of metal antitumor drug indicates to be potential carriers for effective drug delivery.

  5. Preparation and swelling properties of pH-sensitive composite hydrogel beads based on chitosan-g-poly (acrylic acid)/vermiculite and sodium alginate for diclofenac controlled release.

    PubMed

    Wang, Qin; Xie, Xiaoling; Zhang, Xiaowei; Zhang, Junping; Wang, Aiqin

    2010-04-01

    A series of pH-sensitive composite hydrogel beads, chitosan-g-poly (acrylic acid)/vermiculite/sodium alginate (CTS-g-PAA/VMT/SA), was prepared using CTS-g-PAA/VMT composite and SA by Ca(2+) as the crosslinking agent. The structure and morphologies of the developed composite hydrogel beads were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The swelling properties and pH-sensitivity of the beads were investigated. In addition, the drug loading and controlled release behaviors of the beads were also evaluated using diclofenac sodium (DS) as the model drug in stimulated gastric fluids (pH 2.1) and intestinal fluids (pH 6.8). The results indicate that the composite hydrogel beads showed good pH-sensitivity. The release rate of the drug from the composite hydrogel beads is remarkably slowed down, which indicated that incorporating VMT into the composite hydrogel beads can improve the burst release effect of the drug.

  6. 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.

  7. Synthesis and Characterization of Waterborne Fluoropolymers Prepared by the One-Step Semi-Continuous Emulsion Polymerization of Chlorotrifluoroethylene, Vinyl Acetate, Butyl Acrylate, Veova 10 and Acrylic Acid.

    PubMed

    Liu, Hongzhu; Bian, Jiming; Wang, Zhonggang; Hou, Chuan-Jin

    2017-01-22

    Waterborne fluoropolymer emulsions were synthesized using the one-step semi-continuous seed emulsion polymerization of chlorotrifluoroethylene (CTFE), vinyl acetate (VAc), n-butyl acrylate (BA), Veova 10, and acrylic acid (AA). The main physical parameters of the polymer emulsions were tested and analyzed. Characteristics of the polymer films such as thermal stability, glass transition temperature, film-forming properties, and IR spectrum were studied. Meanwhile, the weatherability of fluoride coatings formulated by the waterborne fluoropolymer and other coatings were evaluated by the quick ultraviolet (QUV) accelerated weathering test, and the results showed that the fluoropolymer with more than 12% fluoride content possessed outstanding weather resistance. Moreover, scale-up and industrial-scale experiments of waterborne fluoropolymer emulsions were also performed and investigated.

  8. 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.

  9. 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.

  10. Vinylpyrrolidone-co-(meth)acrylic acid inserts for ocular drug delivery: synthesis and evaluation.

    PubMed

    Barbu, Eugen; Sarvaiya, Indrajeetsinh; Green, Keith L; Nevell, Thomas G; Tsibouklis, John

    2005-09-15

    Copolymeric hydrogels constituting of vinylpyrrolidone and methacrylic or acrylic acid repeat units have been prepared and investigated for their ability to act as controlled release vehicles in ophthalmic drug delivery. The materials were synthesized by radical-induced polymerization in the presence of N,N'-methylenebisacrylamide crosslinker, and the influences of network composition and drug solubility upon the swelling properties, adhesion behavior, and drug release characteristics were studied. In vitro release experiments showed that some of these materials could be useful vehicles for the delivery of drugs such as pilocarpine or chloramphenicol, while in vivo studies, using the rabbit model, confirmed their high potential for the controlled ocular delivery of pilocarpine hydrochloride.

  11. Precision synthesis of bio-based acrylic thermoplastic elastomer by RAFT polymerization of itaconic acid derivatives.

    PubMed

    Satoh, Kotaro; Lee, Dong-Hyung; Nagai, Kanji; Kamigaito, Masami

    2014-01-01

    Bio-based polymer materials from renewable resources have recently become a growing research focus. Herein, a novel thermoplastic elastomer is developed via controlled/living radical polymerization of plant-derived itaconic acid derivatives, which are some of the most abundant renewable acrylic monomers obtained via the fermentation of starch. The reversible addition-fragmentation chain-transfer (RAFT) polymerizations of itaconic acid imides, such as N-phenylitaconimide and N-(p-tolyl)itaconimide, and itaconic acid esters, such as di-n-butyl itaconate and bis(2-ethylhexyl) itaconate, are examined using a series of RAFT agents to afford well-defined polymers. The number-average molecular weights of these polymers increase with the monomer conversion while retaining relatively narrow molecular weight distributions. Based on the successful controlled/living polymerization, sequential block copolymerization is subsequently investigated using mono- and di-functional RAFT agents to produce block copolymers with soft poly(itaconate) and hard poly(itaconimide) segments. The properties of the obtained triblock copolymer are evaluated as bio-based acrylic thermoplastic elastomers.

  12. 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

  13. 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.

  14. Intestinal Targeting of Ganciclovir Release Employing a Novel HEC-PAA Blended Lyomatrix.

    PubMed

    Mabrouk, Mostafa; Mulla, Jameel A S; Kumar, Pradeep; Chejara, Dharmesh R; Badhe, Ravindra V; Choonara, Yahya E; du Toit, Lisa C; Pillay, Viness

    2016-10-01

    A hydroxyethylcellulose-poly(acrylic acid) (HEC-PAA) lyomatrix was developed for ganciclovir (GCV) intestine targeting to overcome its undesirable degradation in the stomach. GCV was encapsulated within the HEC-PAA lyomatrix prepared by lyophilization. Conventional tablets were also prepared with identical GCV concentrations in order to compare the GCV release behavior from the lyomatrix and tablets. GCV incorporation (75.12%) was confirmed using FTIR, DSC, and TGA. The effect of GCV loading on the microstructure properties of the lyomatrix was evaluated by SEM, AFM, and BET surface area measurements. The in vitro drug release study showed steady and rapid release profiles from the GCV-loaded lyomatrix compared with the tablet formulation at identical pH values. Minimum GCV release was observed at acidic pH (≤40%) and maximum release occurred at intestinal pH values (≥90%) proving the intestinal targeting ability of the lyomatrix. Kinetic modeling revealed that the GCV-loaded lyomatrix exhibited zero-order release kinetics (n = 1), while the tablets were best described via the Peppas model. Textural analysis highlighted enhanced matrix resilience and rigidity gradient (12.5%, 20 Pa) for the GCV-loaded lyomatrix compared to the pure (7%, 9.5 Pa) HEC-PAA lyomatrix. Bench-top MRI imaging was used to confirm the mechanism of GCV release behavior by monitoring the swelling and erosion rates. The swelling and erosion rate of the tablets was not sufficient to achieve rapid zero-order GCV release as with the lyomatrix. These combined results suggest that the HEC-PAA lyomatrix may be suitable for GCV intestinal targeting after oral administration.

  15. Accurate determination of residual acrylic acid in superabsorbent polymer of hygiene products by headspace gas chromatography.

    PubMed

    Zhang, Shu-Xin; Chai, Xin-Sheng; Jiang, Ran

    2017-02-17

    This work reports on a method for the determination of residual acrylic acid (AA) in the superabsorbent polymers for hygiene products by headspace analysis. It was based on water extraction for the polymer sample at a room temperature for 50min. Then, the AA in the extractant reacted with bicarbonate solution in a closed headspace sample vial, from which the carbon dioxide generated from the reaction (within 20min at 70°C) was detected by gas chromatography (GC). It was found that there is adsorption partition equilibrium of AA between solid-liquid phases. Therefore, an equation for calculating the total AA content in the original polymers sample was derived based on the above phase equilibrium. The results show that the HS-GC method has good precision (RSD<2.51%) and good accuracy (recoveries from 93 to 105%); the limit of quantification (LOQ) was 373mg/kg. The present method is rapid, accurate, and suitable for determining total residual acrylic acid in a wide variety of applications from processing of superabsorbent polymer to commercial products quality control.

  16. Protein absorption and fouling on poly(acrylic acid)-graft-polypropylene microfiltration membrane

    NASA Astrophysics Data System (ADS)

    Liu, Yanjun; Ma, Huiying; Lv, Chunying; Yang, Jia; Fu, Xueqi

    2009-07-01

    A series of pH-sensitive poly (acrylic acid)-graft-polypropylene hollow fiber microfiltration membranes were prepared by UV-photo-irradiation. Bovine serum albumin (BSA) was chosen as the model protein to investigate its absorption and fouling behaviors on membranes. The results showed that the hydrophilicity of grafted membrane was improved by poly(acrylic acid) chains with parts of membrane pores blocked. The grafted membranes were markedly pH-dependent on the water permeability as pH was altered from 1 to 11. The zeta potential of grafted membranes calculated by streaming potential was negative in most pH range. Electrostatic interaction energy calculated by DLVO theory showed the electric interaction force between grafted membrane and BSA was attractive. With the rise of grafting degree, the electric attractive force between grafted membrane and BSA increased as pH=3 and decreased as pH=8, while it kept basically unchanged as pH=4.7. As a result, most serious fouling was observed as pH=4.7. Grafted membranes had a lower BSA absorption and better antifouling behavior as pH=8, while the opposite result was revealed as pH=3. In conclusion, the absorption and fouling behavior of BSA on membranes was pH-dependent due to the pH-dependence of membrane charge, and the conformation of BSA and grafting chains.

  17. 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.

  18. The synthesis, properties, and applications of hydrophilic polymers and copolymers of hydroxyalkyl esters of acrylic and methacrylic acids

    NASA Astrophysics Data System (ADS)

    Asadov, Z. G.; Aliev, V. S.

    1992-05-01

    The scientific-technical and patent literature on the synthesis of hydroxyalkyl esters of acrylic and methacrylic acids by their catalytic reaction with epoxyalkanes, by the radical copolymerisation and polymerisation of presynthesised monomeric esters, and also by the chemical modification of polymerisation and copolymerisation products is surveyed. A wide variety of physicochemical properties of the polymers and copolymers based on the hydroxyalkyl esters of acrylic and methacrylic acids are described. The principal trends and prospects in the application of the high-molecular-weight products obtained in various branches of the national economy are indicated. The bibliography includes 158 references.

  19. Ionization of amphiphilic acidic block copolymers.

    PubMed

    Colombani, Olivier; Lejeune, Elise; Charbonneau, Céline; Chassenieux, Christophe; Nicolai, Taco

    2012-06-28

    The ionization behavior of an amphiphilic diblock copolymer poly(n-butyl acrylate(50%)-stat-acrylic acid(50%))(100)-block-poly(acrylic acid)(100) (P(nBA(50%)-stat-AA(50%))(100)-b-PAA(100), DH50) and of its equivalent triblock copolymer P(nBA(50%)-stat-AA(50%))(100)-b-PAA(200)-b-P(nBA(50%)-stat-AA(50%))(100) (TH50) were studied by potentiometric titration either in pure water or in 0.5 M NaCl. These polymers consist of a hydrophilic acidic block (PAA) connected to a hydrophobic block, P(nBA(50%)-stat-AA(50%))(100), whose hydrophobic character has been mitigated by copolymerization with hydrophilic units. We show that all AA units, even those in the hydrophobic block could be ionized. However, the AA units within the hydrophobic block were less acidic than those in the hydrophilic block, resulting in the preferential ionization of the latter block. The preferential ionization of PAA over that of P(nBA(50%)-stat-AA(50%))(100) was stronger at higher ionic strength. Remarkably, the covalent bonds between the PAA and P(nBA(50%)-stat-AA(50%))(100) blocks in the diblock or the triblock did not affect the ionization of each block, although the self-association of the block copolymers into spherical aggregates modified the environment of the PAA blocks compared to when PAA was molecularly dispersed.

  20. Pulsed and continuous wave acrylic acid radio frequency plasma deposits: plasma and surface chemistry.

    PubMed

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

    2007-04-05

    Plasma polymers have been formed from acrylic acid using a pulsed power source. An on-pulse duration of 100 micros was used with a range of discharge off-times between 0 (continuous wave) and 20,000 micros. X-ray photoelectron spectroscopy (XPS) has been used in combination with trifluoroethanol (TFE) derivatization to quantify the surface concentration of the carboxylic acid functionality in the deposit. Retention of this functionality from the monomer varied from 2% to 65%. When input power was expressed as the time-averaged energy per monomer molecule, E(mean), the deposit chemistry achieved could be described using a single relationship for all deposition conditions. Deposition rates were monitored using a quartz crystal microbalance, which revealed a range from 20 to 200 microg m(-2) s(-1), and these fell as COOH functional retention increased. The flow rate was found to be the major determinant of the deposition rate, rather than being uniquely defined by E(mean), connected to the rate at which fresh monomer enters the system in the monomer deficient regime. The neutral species were collected in a time-averaged manner. As the energy delivered per molecule in the system (E(mean)) decreased, the amount of intact monomer increased, with the average neutral mass approaching 72 amu as E(mean) tends to zero. No neutral oligomeric species were detected. Langmuir probes have been used to determine the temporal evolution of the density and temperature of the electrons in the plasma and the plasma potential adjacent to the depositing film. It has been found that even 500 micros into the afterglow period that ionic densities are still significant, 5-10% of the on-time density, and that ion accelerating sheath potentials fall from 40 V in the on-time to a few volts in the off-time. We have made the first detailed, time- and energy-resolved mass spectrometry measurements in depositing acrylic acid plasma. These have allowed us to identify and quantify the positive ion

  1. 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.

  2. Radiation Synthesis of Poly(Starch/Acrylic acid) pH Sensitive Hydrogel for Rutin Controlled Release.

    PubMed

    Abdel Ghaffar, A M; Radwan, Rasha R; Ali, H E

    2016-11-01

    The copolymerization of starch with acrylic acid AAc using direct gamma radiation technique was performed. The effect of AAc concentrations on the gel (%) and swelling behavior were investigated. It is found that as AAc concentrations increase both gel(%) and swelling behavior increase. The Poly(starch/acrylic acid) (1:10wt%) hydrogel were selected due to its high swelling properties. From the in-vitro release study of the rutin-loaded hydrogel it is observed that it is strong pH-dependent release behavior, thus offering a maximum release as pH increased. The dextran sulphate sodium (DSS)-induced rat colitis model was treated with rutin-loaded Poly(starch/acrylic acid) (1:10wt%) hydrogel and free rutin solution by oral administration. Colitic control group showed a significant elevation in colon/body weight ratio, myeloperoxgidase activity, tumor necrosis factor, nitric oxide and malondialdehyde levels. However, glutathione level was reduced. It was found that the rutin-loaded hydrogel was more efficient than free rutin as evidenced by improvement of all measured parameters. These effects were confirmed histopathologically and may be attributed to its ability to control delivery of rutin to colon with minor early release of rutin before colon. The Poly(starch/acrylic acid) (1:10wt%) can represent a pivotal anti-inflammatory approach for patients with inflammatory bowel disease in order to increase efficacy and reduce toxicity.

  3. 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...

  4. 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.

  5. 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 ...

  6. Introduction of poly[(2-acryloyloxyethyl trimethyl ammonium chloride)-co-(acrylic acid)] branches onto starch for cotton warp sizing.

    PubMed

    Shen, Shiqi; Zhu, Zhifeng; Liu, Fengdan

    2016-03-15

    An attempt has been made to reveal the effect of amphoteric poly(2-acryloyloxyethyl trimethyl ammonium chloride-co-acrylic acid) [P(ATAC-co-AA)] branches grafted onto the backbones of starch upon the adhesion-to-cotton, film properties, and desizability of maize starch for cotton warp sizing. Starch-g-poly[(2-acryloyloxyethyl trimethyl ammonium chloride)-co-(acrylic acid) [S-g-P(ATAC-co-AA)] was prepared by the graft copolymerization of 2-acryloyloxyethyl trimethyl ammonium chloride (ATAC) and acrylic acid (AA) with acid-converted starch (ACS) in aqueous medium using Fe(2+)-H2O2 initiator. The adhesion was evaluated in term of bonding strength according to the FZ/T 15001-2008 whereas the film properties considered included tensile strength, work and percentage elongation at break. The evaluation was undertaken through the comparison of S-g-P(ATAC-co-AA) with ACS, starch-g-poly(acrylic acid), and starch-g-poly(2-acryloyloxyethyl trimethyl ammonium chloride). It was found that the amphoteric branch was able to significantly improve the adhesion and mitigate the brittleness of starch film. Zeta potential of cooked S-g-P(ATAC-co-AA) paste, depending on the mole ratio of ATAC to AA units on P(ATAC-co-AA) branches, had substantial effect on the adhesion and desizability. Increasing the mole ratio raised the potential, which favored the adhesion but disfavored the removal of S-g-P(ATAC-co-AA) from sized cotton warps. Electroneutral S-g-P(ATAC-co-AA) was superior to negatively grafted starch in adhesion and to positively grafted starch in desizability. Generally, it showed better sizing property than ACS, starch-g-poly(acrylic acid), and starch-g-poly(2-acryloyloxyethyl trimethyl ammonium chloride), and had potential in the application of cotton warp sizing.

  7. Interpolymer complexes of poly(acrylic acid) and chitosan: influence of the ionic hydrogel-forming medium.

    PubMed

    de la Torre, Paloma M; Torrado, Susana; Torrado, Santiago

    2003-04-01

    Non-covalent polyionic complexes were developed for localized antibiotic delivery in the stomach. Freeze-dried interpolymer complexes based on polyacrylic acid (PAA) and chitosan (CS) were prepared in a wide range of copolymer compositions by dissolving both polymers in acidic conditions. The influence of hydrogel-forming medium on the swelling and drug release was evaluated. The properties of these complexes were investigated by using scanning electron microscopy, dynamic swelling/eroding and release experiments in enzyme-free simulated gastric fluid (SGF). The electrostatic polymer/polymer interactions generate polyionic complexes with different porous structures. In a low pH environment, the separation of both polymer chains augmented as the amount of cationic and carboxilic groups increased within the network. However, the presence of higher amount of ions in the hydrogel-forming medium produced a network collapse, decreasing the maximum swelling ratio in SGF. PAA:CS:A (1:2.5:2)-1.75 M complexes released around 54% and 71% of the amoxicillin in 1 and 2 h, respectively, in acidic conditions. A faster drug release from this interpolymer complex was observed when the ionic strength of the hydrogel-forming medium increased. Complexes with a high amount of both polymer chains within the network, PAA:CS:A(2.5:5:2), showed a suitable amoxicillin release without being affected by an increased amount of ions in the hydrogel-forming medium. These freeze-dried interpolymer complexes could serve as potential candidates for amoxicillin delivery in an acidic enviroment.

  8. 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.

  9. Grafting of acrylic acid on etched latent tracks induced by swift heavy ions on polypropylene films

    NASA Astrophysics Data System (ADS)

    Mazzei, R.; Fernández, A.; García Bermúdez, G.; Torres, A.; Gutierrez, M. C.; Magni, M.; Celma, G.; Tadey, D.

    2008-06-01

    In order to continue with a systematic study that include different polymers and monomers, the residual active sites produced by heavy ion beams, that remain after the etching process, were used to start the grafting process. To produce tracks, foils of polypropylene (PP) were irradiated with 208Pb of 25.62 MeV/n. Then, these were etched and grafted with acrylic acid (AA) monomers. Experimental curves of grafting yield as a function of grafting time with the etching time as a parameter were measured. Also, the grating yield as a function of the fluence and etching time was obtained. In addition, the permeation of solutions, with different pH, through PP grafted foils was measured.

  10. Grafting of acrylic acid onto polypropylene films irradiated with argon ions

    NASA Astrophysics Data System (ADS)

    Massa, G.; Mazzei, R.; García Bermúdez, G.; Filevich, A.; Smolko, E.

    2005-07-01

    Polypropylene (PP) foils were irradiated with 100 keV energy Argon ions at different fluences ranging from 1012 up to 2 × 1015 cm-2 and then grafted with acrylic acid (AA). The grafting yield was measured by weight difference and the structural changes on the films were analysed using Fourier transform infrared spectroscopy (FTIR). Different parameters that determined the grafting process such us fluence, grafting time and monomer concentration were analysed. The grafting reached an optimum value at 79% in aqueous solution at 30 min grafting time. The grafting yield as a function of the ion fluence plot, presented a maximum value, as previously found in a study of heavy beam on polymers.

  11. 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.

  12. 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.

  13. Radiation-induced grafting of diallyldimethylammonium chloride onto acrylic acid grafted polyethylene

    NASA Astrophysics Data System (ADS)

    Francis, Sanju; Dhanawade, B. R.; Mitra, D.; Varshney, Lalit; Sabharwal, Sunil

    2009-01-01

    Diallyldimethylammonium chloride (DADMAC) was grafted onto polyethylene (PE) films by a double grafting procedure. The PE film was initially modified by grafting acrylic acid (AA), through a mutual irradiation method. AA-g-PE film, thus obtained was subjected to subsequent radiation grafting reaction of DADMAC, to give a DADMAC-g-AA-g-PE film having a comb-type structure. The influence of different conditions, such as the extent of AA grafting, DADMAC concentration, absorbed dose and dose rate, on the grafting yield of DADMAC was investigated. A maximum DADMAC grafting of 30% was achieved. The equilibrium degree of swelling (EDS) of the grafted films were gravimetrically determined. TGA and FT-IR techniques were employed to characterize the grafted PE films.

  14. 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.

  15. Poly (acrylic acid)-capped lanthanide-doped BaFCl nanocrystals: synthesis and optical properties.

    PubMed

    Ju, Qiang; Luo, Wenqin; Liu, Yongsheng; Zhu, Haomiao; Li, Renfu; Chen, Xueyuan

    2010-07-01

    Water-soluble lanthanide-doped BaFCl nanophosphors with the surface functionalized by a layer of poly (acrylic acid) are synthesized via a facile one-step solvothermal method. Intense long-lived luminescence is realized from visible to near-infrared (NIR) by doping with different lanthanide ions. The emission and excitation spectra of Eu(3+) indicate that the doped lanthanide ions occupy a site close to the surface of the nanoparticles. Strong NIR emissions of Nd(3+) and green luminescence of Tb(3+) using Ce(3+) as sensitizers are also achieved in BaFCl nanoparticles. The synthesized nanoparticles featuring long-lived luminescence in either visible or NIR regions may have potential applications as luminescent labels for biological applications.

  16. Adsorption of poly acrylic acid onto the surface of calcite: an experimental and simulation study.

    PubMed

    Sparks, David J; Romero-González, Maria E; El-Taboni, Elfateh; Freeman, Colin L; Hall, Shaun A; Kakonyi, Gabriella; Swanson, Linda; Banwart, Steven A; Harding, John H

    2015-11-07

    Macromolecular binding to minerals is of great importance in the formation of biofilms, and carboxylate functional groups have been found to play a pivotal role in the functioning of these macromolecules. Here we present both fluorescence time-resolved anisotropy measurements and simulation data on the conformational behaviour and binding of a poly acrylic acid polymer. In solution the polymer exhibits a pH dependent behaviour, with a coiled conformation at a low pH and extended conformation at higher pH values. The polymer is readily adsorbed on the surface of calcite, preferring to bind in an extended conformation, with the strength of the adsorption dependent on the pH and presence of counter ions. We discuss the reasons why the calculated adsorption free energy differs from that obtained from a Langmuir isotherm analysis, showing that they refer to different quantities. The enhanced binding of the extended conformations shows the importance of flexibility in the binding of macromolecules.

  17. 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.

  18. 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.

  19. Properties of the acrylic acid polymers obtained by atmospheric pressure plasma polymerization

    NASA Astrophysics Data System (ADS)

    Topala, Ionut; Dumitrascu, Nicoleta; Popa, Gheorghe

    2009-01-01

    Plasma polymers of acrylic acid were obtained using an atmospheric pressure discharge system. The plasma polymerization reactor uses a dielectric barrier discharge, with the polyethylene terephthalate dielectric acting as substrate for deposition. The plasma was characterized by specific electrical measurements, monitoring the applied voltage and the discharge current. Based on the spatially resolved optical emission spectroscopy, we analyzed the distribution of the excited species in the discharge gap, specific plasma temperatures (vibrational and gas temperatures) being calculated with the Boltzmann plot method. The properties of the plasma polymer films were investigated by contact angle measurements, infrared and UV-Vis spectroscopy, scanning electron microscopy. The films produced by plasma polymerization at atmospheric pressure showed a hydrophilic character, in correlation with the strong absorbance of OH groups in the FTIR spectrum. Moreover, the surface of the plasma polymers at micrometric scale is smooth and free of defects without particular features.

  20. Corrosion Inhibitive Evaluation of an Environmentally Friendly Water-Base Acrylic Terpolymer on Mild Steel in Hydrochloric Acid Media

    NASA Astrophysics Data System (ADS)

    Azghandi, Mojtaba Vakili; Davoodi, Ali; Farzi, Gholam Ali; Kosari, Ali

    2013-12-01

    The corrosion inhibitive performance of an environmentally friendly water-base acrylic terpolymer [methyl methacrylate/Butyl Acrylate/Acrylic acid (ATP)] on mild steel in 1 M HCl was investigated by alternating current and direct current electrochemical techniques and the quantum chemical method. An efficiency of more than 97 pct was obtained with 0.8 mmol/L ATP. The increase in inhibitor concentration and immersion time has a positive effect, while the temperature influence is negligible on the inhibitor efficiency. The present terpolymer obeys the Langmuir isotherm, and thermodynamic calculation reveals a chemisorption type on the surface. Density functional calculations showed that the lone pairs of electrons of oxygen in the structure of three monomers are suitable sites to adsorb onto the metal surface. Finally, in the presence of ATP, a decrease in surface roughness and corrosion attacks was demonstrated by atomic force microscopy and optical microscopy examinations, respectively.

  1. Biodiesel production from rubber seed oil using poly (sodium acrylate) supporting NaOH as a water-resistant catalyst.

    PubMed

    Yang, Ru; Su, Mengxing; Zhang, Jianchun; Jin, Fuqiang; Zha, Chunhong; Li, Min; Hao, Xinmin

    2011-02-01

    Poly (sodium acrylate) supporting NaOH (NaOH/NaPAA) was prepared by in situ polymerization of aqueous solution of acrylic acid with an over-neutralization by adding excess of NaOH. NaOH/NaPAA presented a promising selectivity for water absorbency and good water retention with negligible swelling capacity in the organic solvents of methanol, glycerol, rubber seed oil methyl esters, and rubber seed oil. NaOH/NaPAA catalysts showed a basic strength of 15.0PAA catalysts exhibited almost the same catalytic activity in the transesterification of rubber seed oil with methanol under the optimized reaction conditions compared to conventional homogeneous NaOH catalyst. Furthermore, the functional absorbent/catalyst system presented a good water resistance in the transesterification which retained high catalytic activity when a water concentration in the reaction system was less than 2 wt.%.

  2. One-step formation of multiple Pickering emulsions stabilized by self-assembled poly(dodecyl acrylate-co-acrylic acid) nanoparticles.

    PubMed

    Zhu, Ye; Sun, Jianhua; Yi, Chenglin; Wei, Wei; Liu, Xiaoya

    2016-09-13

    In this study, a one-step generation of stable multiple Pickering emulsions using pH-responsive polymeric nanoparticles as the only emulsifier was reported. The polymeric nanoparticles were self-assembled from an amphiphilic random copolymer poly(dodecyl acrylate-co-acrylic acid) (PDAA), and the effect of the copolymer content on the size and morphology of PDAA nanoparticles was determined by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The emulsification study of PDAA nanoparticles revealed that multiple Pickering emulsions could be generated through a one-step phase inversion process by using PDAA nanoparticles as the stabilizer. Moreover, the emulsification performance of PDAA nanoparticles at different pH values demonstrated that multiple emulsions with long-time stability could only be stabilized by PDAA nanoparticles at pH 5.5, indicating that the surface wettability of PDAA nanoparticles plays a crucial role in determining the type and stability of the prepared Pickering emulsions. Additionally, the polarity of oil does not affect the emulsification performance of PDAA nanoparticles, and a wide range of oils could be used as the oil phase to prepare multiple emulsions. These results demonstrated that multiple Pickering emulsions could be generated via the one-step emulsification process using self-assembled polymeric nanoparticles as the stabilizer, and the prepared multiple emulsions have promising potential to be applied in the cosmetic, medical, and food industries.

  3. pH-Responsive Behavior of Poly(acrylic acid) Brushes of Varying Thickness

    NASA Astrophysics Data System (ADS)

    Yadav, Vivek; Robertson, Megan; Conrad, Jacinta

    2015-03-01

    We have investigated the pH-dependent response of polyelectrolyte brushes of varying thickness. Our model system consists of poly(acrylic acid) brushes, which change from hydrophobic and neutral at low pH to hydrophilic and negatively charged at high pH, synthesized using a grafting-from approach at constant grafting density. As the polymer brush thickness increased, the brushes exhibited greater hysteresis in static water contact angle as a function of pH. We extracted the pKa of the polymer brushes from contact angle measurements. The relationship between the pKa and brush thickness depended on the order in which the brushes were exposed to solutions of varying pH: pKa decreased on increasing brush thickness when going from basic to acidic medium whereas pKa increased on increasing brush thickness when going from acidic to basic medium. We speculate that the origin of hysteresis can be explained by pH-dependent conformational changes in these polyelectrolyte brushes.

  4. 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.

  5. Disinfection efficiency of peracetic acid (PAA): inactivation of coliphages and bacterial indicators in a municipal wastewater plant.

    PubMed

    Zanetti, F; De Luca, G; Sacchetti, R; Stampi, S

    2007-11-01

    The aim of the study was to assess the efficiency of low doses of peracetic acid against viral and bacterial indicators in wastewater and to evaluate if the treatment allows regulatory requirements to be satisfied. A total of 31 samplings were carried out, each involving the collection of secondary effluent and of effluent disinfected with 1.2 or 1.5 mg l(-1) of peracetic acid (contact time 20 minutes). In each sample were measured: somatic coliphages, F-specific RNA bacteriophages, Escherichia coli, total and faecal coliforms, enterococci. Peracetic acid disinfection showed significant differences between the reductions of the microorganisms tested: E. coli showed the highest reduction (1.78 and 2.43 Log respectively with 1.2 and 1.5 mg l(-1) of peracetic acid) and phages the lowest (ranging between 0.52 and 0.60 Log). Only a concentration of 1.5 mg l(-1) of peracetic acid would enable the effluent to be discharged into surface waters in compliance with Italian regulations. The variability of microbial resistance against the peracetic acid disinfection treatment, underlines the importance of assessing disinfection efficiency by using more than one indicator microorganism. The detection of E. coli could be usefully accompanied by tests for more resistant microorganisms such as enterococci or coliphages. In conclusion, peracetic acid can be used for the disinfection of effluents even at low doses, with the advantage of reducing costs and preventing the formation of significant amounts of genotoxic by-products.

  6. 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.

  7. 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.

  8. Discovery and SARs of Trans-3-Aryl Acrylic Acids and Their Analogs as Novel Anti- Tobacco Mosaic Virus (TMV) Agents

    PubMed Central

    Wu, Meng; Wang, Ziwen; Meng, Chuisong; Wang, Kailiang; Hu, Yanna; Wang, Lizhong; Wang, Qingmin

    2013-01-01

    A series of trans-3-aryl acrylic acids 1–27 and their derivatives 28–34 were prepared and evaluated for their antiviral activity against tobacco mosaic virus (TMV) for the first time. The bioassay results showed that most of these compounds exhibited good antiviral activity against TMV, of which compounds 1, 5, 6, 20, 27 and 34 exhibited significantly higher activity against TMV than commercial Ribavirin both in vitro and in vivo. Furthermore, these compounds have more simple structure than commercial Ribavirin, and can be synthesized more efficiently. These new findings demonstrate that trans-3-aryl acrylic acids and their derivatives represent a new template for antiviral studies and could be considered for novel therapy against plant virus infection. PMID:23418574

  9. 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

    2014-09-03

    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.

  10. Removal of dorzolamide from biomedical wastewaters with adsorption onto graphite oxide/poly(acrylic acid) grafted chitosan nanocomposite.

    PubMed

    Kyzas, George Z; Bikiaris, Dimitrios N; Seredych, Mykola; Bandosz, Teresa J; Deliyanni, Eleni A

    2014-01-01

    A novel graphite oxide/poly(acrylic acid) grafted chitosan nanocomposite (GO/CSA) was prepared and used as biosorbent for the removal of pharmaceutical compound (dorzolamide) from biomedical synthetic wastewaters. The performance was evaluated taking into account pH, kinetics and thermodynamics of adsorption. GO/CSA presented higher adsorption capacity in comparison with the parent materials (graphite oxide and poly(acrylic acid) grafted chitosan). All adsorbents prepared were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and potentiometric titration. The surface features were also evaluated after the dorzolamide adsorption in order to derive the adsorption mechanism. It was suggested that the reactive groups of GO and CSA can interact with the amino groups of dorzolamide and mainly the abundance of carboxyl groups of GO/CSA composite was the main reason for its enhanced adsorption capacity.

  11. The synthesis and in vitro characterization of the mucoadhesion and swelling of poly(acrylic acid) hydrogels.

    PubMed

    Warren, S J; Kellaway, I W

    1998-05-01

    The purpose of this research was to synthesize insoluble, mucoadhesive hydrogels by crosslinking linear poly(acrylic acid) with sucrose and investigate the relationship between hydrogel crosslink density, swelling, and in vitro mucoadhesion. A condensation reaction was employed to synthesize the hydrogels and crosslink density was varied by altering sucrose concentration and cure time. Equilibrium swelling at pH 7.4 was measured both gravimetrically and geometrically. In vitro mucoadhesion was determined by a tensile technique. Equilibrium swelling studies indicated that the crosslink density was proportional to both sucrose concentration and duration of cure time. In vitro mucoadhesive properties of the hydrogels improved as crosslink density increased. This was attributed to an increase in poly(acrylic acid) chain density/unit area of the equilibrium swollen hydrogel, which promoted interaction of the mucoadhesive and glycoprotein polymer chains.

  12. Experimental study of the antithrombogenic behavior of Dacron vascular grafts coated with hydrophilic acrylic copolymers bearing salicylic acid residues.

    PubMed

    San Román, J; Buján, J; Bellón, J M; Gallardo, A; Escudero, M C; Jorge, E; de Haro, J; Alvarez, L; Castillo-Olivares, J L

    1996-09-01

    The objective of the present work was study of the behavior of active coatings of hydrophilic acrylic polymers bearing salicylic acid residues linked covalently to the macromolecular chains, after their application to woven and knitted Dacron vascular grafts. In vitro tests were carried out under dynamic flow conditions using equipment especially designed to reproduce physiologic conditions, to determine the retention of the coating using a saline solution. Ex vivo tests were carried out in an extracorporeal circuit using the dog as an animal model. The study of the deposition of platelets was followed by labeling of autologous platelets with 111In-oxine, as well as by analysis of the surfaces of the prostheses by scanning electron microscopy. An application of thin coatings of hydrophilic acrylic copolymers improves the antithrombogenicity of the vascular grafts with respect to the uncoated prosthesis. The presence of relatively small amounts of units bearing salicylic acid residues in the copolymer chains (5-20 wt %) gives good results when they are applied to woven and knitten Dacron meshes which have been quantified by analysis of the percentage of radiotracer on the surface of the vascular grafts tested in ex vivo experiments. The salicylic acid residues are released slowly to the medium by hydrolysis of the reversible covalent bonds of this compound to the acrylic macromolecular chains, which provides an additional antiaggregating effect for platelets. The polymeric coating forms a thin active film which improves the antithrombogenic properties of the surface of woven or knitted Dacron vascular grafts in ex vivo experiments.

  13. Isotherm and kinetics study for acrylic acid removal using powdered activated carbon.

    PubMed

    Kumar, Arvind; Prasad, B; Mishra, I M

    2010-04-15

    The potential of powdered activated carbon (PAC) for the adsorption of acrylic acid (AA) from aqueous solution was studied at the initial concentration (C(0)) in the range of 50-500 mg/l over the temperature range of 303-348 K. The equilibrium adsorption studies were carried out to evaluate the effect of adsorbent dosage and contact time, change in pH by adding adsorbents and the initial concentration. Langmuir, Freundlich and Redlich-Peterson (R-P) equilibrium isotherm models were tested to represent the data. Error functions were used to test their validity to fit of the adsorption data with the isotherm and kinetic models. The Freundlich isotherm equation is found to best represent the equilibrium separation data in the temperature range of 303-348 K. The maximum adsorption capacity of AA onto PAC was obtained as q(m)=36.23 mg/g with an optimum PAC dosage w=20 g/l at 303 K for C(0)=100 mg/l. The pseudo-second-order kinetics is found to represent the experimental AA-PAC data. The negative value of DeltaG(ad)(o) (-16.60 to -18.18 kJ/mol K) indicate the feasibility and spontaneity of the adsorption process.

  14. 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.

  15. Novel poly(ethylene-co-acrylic acid) nanofibrous biomaterials for peptide synthesis and biomedical applications.

    PubMed

    Xiang, Bei; Sun, Gang; Lam, Kit S; Xiao, Kai

    2010-10-01

    Poly(ethylene-co-acrylic acid) (PE-co-AA) fibers in sizes of 200-500 nm were prepared by using a novel melt-extrusion-extraction fabrication process. The thermoplastic nanofibers could be controllably dispersed and reassembled by a novel solvent exchange filtration method. The dispersed PE-co-AA nanofibers possess active surface areas and could directly conduct chemical reactions on surfaces. Surface modifications and organic synthesis on the nanofibers were proven effective and controllable after the dispersion. Multistep synthesis of biomolecules, such as peptide ligand HWRGWV against Fc portion of human IgG, was successful. The surface-anchored ligand has shown bioactivity through selective binding to and staining by human IgG-alkaline phosphatase conjugate. Another peptide, LXY3, a selective cyclic peptide ligand against alpha3beta1 integrin of MDA-MB-231 breast cancer cells, was also prepared on the surfaces of the dispersed nanofibers. The results showed that MDA-MB-231 cells were able to specifically bind to and grow on surfaces of the nanofibers that were functionalized with LXY3.

  16. Synthesis and characterization of acrylamide-acrylic acid hydrogels and adsorption of some textile dyes

    NASA Astrophysics Data System (ADS)

    Duran, Sibel; Şolpan, Dilek; Güven, Olgun

    1999-05-01

    Acrylamide (AAm)-acrylic acid (AAc) hydrogels have been prepared at AAm initial compositions of 15%, 20% and 30%. AAm-AAc monomer mixtures have been irradiated in a 60Co-γ source at different doses and percent conversions have been determined gravimetrically. 100% conversion of monomers into hydrogels was achieved at 8 kGy dose. These hydrogels were swollen in distilled water at pH 3.03, 4.18, 4.68, 5.05, 5.30, 6.0, 7.0, 8.0. The results of swelling tests at pH 8.0 indicated that poly(AAm-AAc) hydrogels prepared from solution containing 15% (mol%) AAm showed maximum % swelling as 3000%. Poly(AAm-AAc) hydrogels have been considered for the removal of some textile dyes from aqueous solutions. Among the two common textile dyes tested, Janus Green B (JGB) has showed the highest adsorption capacity while Congo Red (CR) was not adsorbed by these hydrogels. Adsorption isotherms were constructed for JGB and poly(AAm/AAc) gel systems. It is concluded that cross-linked poly(AAm/AAc) hydrogels can be successfully used in the purification of waste water containing certain textile dyes.

  17. Cadmium ion-doped magnetic poly(styrene-acrylic acid) nanospheres for sensitive electrochemical immunoassay.

    PubMed

    Zhang, Bing; Cui, Yuling; Liu, Bingqian; Chen, Huafeng; Chen, Guonan; Tang, Dianping

    2012-05-15

    A novel class of molecular tags, cadmium ion-doped magnetic poly(styrene-acrylic acid) nanospheres (Cd-MPSA), was first synthesized and functionalized with polyclonal rabbit anti-human luteinizing hormone antibodies (PAb(2)) for highly efficient electrochemical immunoassay of luteinizing hormone (LH). Transmission electron microscope (TEM) and Fourier transform infrared spectroscope (FTIR) were employed to characterize the prepared Cd-MPSA. By using Cd-MPSA-labeled PAb(2) as molecular tags, a novel sandwich-type immunoassay protocol was built for determination of LH on monoclonal mouse anti-human luteinizing hormone antibody (MAb(1))-functionalized gold electrode. The assay was carried out in pH 5.3 HAc-NaAc buffer solution by square wave voltammetry (SWV). The signal was obtained by the reduction of the doped cadmium ions in the Cd-MPSA. Under optimal conditions, the currents increased with the increasing LH level in the sample, and exhibited a linear range from 0.25 to 240 mIU mL(-1) with a detection limit of 0.08 mIU mL(-1) LH at 3s(B). The precision, reproducibility, and specificity were acceptable. No obvious difference was encountered in the analysis of spiking LH samples into newborn calf serum with the referenced values.

  18. 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.

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

    PubMed Central

    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. PMID:25755999

  20. 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.

  1. 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.

  2. Light scattering study of partially ionized poly(acrylic acid) systems : comparison between gels and solutions

    NASA Astrophysics Data System (ADS)

    Moussaid, A.; Munch, J. P.; Schosseler, F.; Candau, S. J.

    1991-06-01

    Static and quasielastic light scattering experiments have been performed on the reaction bath of partially neutralized poly(acrylic acid) solutions and gels. The intensity scattered from gels is independent on the scattering wavevector, giving thus evidence that the gels are homogeneous at the scale of the wavelength of the light, contrary to what is generally observed in neutral gels. The comparison of the time and ensemble averages of the autocorrelation function of scattered light intensity shows that the gels behave with respect to that experiment as ergodic media. The variations of the intensity scattered from gels and solutions, with the ionization degree and the polymer concentration were found to be in good agreement with those predicted from simple theoretical arguments. The variations of the cooperative diffusion with these same parameters were found similar for gels and solutions. Des mesures de diffusion statique et quasiélastique de la lumière ont été effectuées sur des solutions et des gels d'acide poly(acrylique) partiellement ionisés. L'intensité diffusée par les gels est indépendante du vecteur d'onde de transfert, ce qui montre leur homogénéité, contrairement au cas des gels neutres. La comparaison des moyennes temporelle et spatiale de la fonction d'autocorrélation de l'intensité de la lumière diffusée montre que ces gels se comportent comme des milieux ergodiques. Les variations de l'intensité diffusée par les gels et les solutions en fonction de la concentration en polymère et du degré d'ionisation sont en bon accord avec les prédictions théoriques. Les variations du coefficient de diffusion avec ces mêmes paramètres sont identiques pour les gels et les solutions.

  3. 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

  4. Reversible fluorescence quenching by micelle selective benzophenone-induced interactions between brij micelles and polyacrylic acids: implications for chemical sensors.

    PubMed

    Bandyopadhyay, Prasun; Ghosh, Amit K

    2010-09-09

    The fluorescence response of pyrene has been studied in the presence of nonionic brij micelles and poly(acrylic acid) (PAA) with benzophenone (BP) as a neutral hydrophobic quencher. Pyrene emission is quenched ("off" state) in the presence of BP in brij 35 (polyoxyethylene-23-lauryl ether) and brij 56 (polyoxyethylene-10-cetyl ether) micelles. Quenched pyrene emission is selectively recovered ("on" state) for brij 35 micelles with the addition of PAA (starting conc 2.0 x 10(-5) M). Due to the interaction of PAA and brij 35 micelles and the relatively easier accessibility of PAA polymer chains near the bulky polyoxyethylene chain of brij 35 micelles, the chances of BP partition inside the hydrophobic polymer coil are more compared to brij 56 micelles. The PAA sensing ability of the "brij 35:pyrene:BP" system is dependent on the molecular weight (M) of the polymer. Fluorescence recovery has been observed with PAA (M approximately 150000) and complete recovery has been recorded with high M of PAA (M approximately 450000); however, no fluorescence change is observed in the presence of low M of PAA (M approximately 2000). In solution, such selective reversible fluorescence quenching has the potential for a new class of highly sensitive chemical sensor systems.

  5. Application of Nano Fe(III)-Tannic Acid Complexes in Modifying Aqueous Acrylic Latex for Controlled-Release Coated Urea.

    PubMed

    Shen, Yazhen; Du, Changwen; Zhou, Jianmin; Ma, Fei

    2017-02-08

    Acrylic latexes are valuable waterborne materials used in controlled-release fertilizers. Controlled-release urea coated with these latexes releases a large amount of nutrients, making it difficult to meet the requirement of plants. Herein, Fe(III)-tannic acid (TA) complexes were blended with acrylic latex and subsequently reassembled on a surface of polyacrylate particles. These complexes remarkably retarded the release of urea (the preliminary solubility was decreased from 22.3 to 0.8%) via decreasing the coating tackiness (Tg was increased from 4.17 to 6.42 °C), increasing the coating strength (tensile stress was improved from 3.88 to 4.45 MPa), and promoting the formation of denser structures (surface tension was decreased from 37.37 to 35.94 mN/m). Overall, our findings showed that a simple blending of Fe(III)-TA complexes with acrylic latex produces excellent coatings that delay the release of urea, which demonstrates great potential for use in controlled-release fertilizers coated with waterborne polymers.

  6. 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

  7. Adsorption of low cross-linking density hydrogel OMMT/acid hydrolysis lignin grafted polyacrylic acid for Cd (II)

    NASA Astrophysics Data System (ADS)

    Lian, Enxiao; Shi, Ruoli; Deng, Yilin; Zhu, Hongjun; Ma, Yanli

    2017-03-01

    Organic montmorillonite/acid hydrolysis lignin graft poly (acrylic acid) composite superabsorbent (LBPAA/OMMT) was prepared by radical copolymerization of acrylic acid and acid hydrolysis lignin, and OMMT was homogeneous dispersed into hydrogels of LBPAA through supersonic irradiation. Persulphate ammonium was used as an initiator, and N, N'-ethylene bis-acrylamide (MBA) as a crosslinker. Adsorption behavior of water and Cd (II) ion on LBPAA/OMMT were investigated. The biggest capacity of adsorption for Cd (II) is PAA (0.6240 mmol/g). The ΔrH0 values of PAA, LBPAA, and LBPAA/OMMT were found as 116.71, 117.8, 125.15kJ mol-1 for Cd (II), respectively. Negative values of ΔrG0 indicates the spontaneous nature of the reaction.

  8. Algal toxicity of the alternative disinfectants performic acid (PFA), peracetic acid (PAA), chlorine dioxide (ClO2) and their by-products hydrogen peroxide (H2O2) and chlorite (ClO2(-)).

    PubMed

    Chhetri, Ravi Kumar; Baun, Anders; Andersen, Henrik Rasmus

    2016-12-01

    Environmental effect evaluation of disinfection of combined sewer overflow events with alternative chemical disinfectants requires that the environmental toxicity of the disinfectants and the main by-products of their use are known. Many disinfectants degrade quickly in water which should be included in the evaluation of both their toxicity as determined in standardized tests and their possible negative effect in the water environment. Here we evaluated according to the standardized ISO 8692 test the toxicity towards the green microalgae, Pseudokirchneriella subcapitata, of three disinfectants: performic acid (PFA), peracetic acid (PAA) and chlorine dioxide (ClO2) as well as two by-products of their use: hydrogen peroxide (H2O2) and chlorite. All of the five chemicals investigated showed clear toxicity to the algae with well-defined dose response curves. The EC50 values ranged from 0.16 to 2.9mg/L based on nominal concentrations leading to the labeling of the chemicals as either toxic or very toxic. The five investigated chemicals decreased in toxicity in the order chlorine dioxide, performic acid, peracetic acid, chlorite and hydrogen peroxide. The stability of the chemicals increased in the same order as the toxicity decrease. This indicates that even though ClO2 has the highest environmental hazard potential, it may still be suitable as an alternative disinfectant due to its rapid degradation in water.

  9. 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.

  10. Design and development of pH-responsive HSPC:C12H25-PAA chimeric liposomes.

    PubMed

    Naziris, Nikolaos; Pippa, Natassa; Meristoudi, Anastasia; Pispas, Stergios; Demetzos, Costas

    2017-06-01

    The application of stimuli-responsive medical practices has emerged, in which pH-sensitive liposomes figure prominently. This study investigates the impact of the incorporation of different amounts of pH-sensitive polymer, C12H25-PAA (poly(acrylic acid) with a hydrophobic end group) in l-α-phosphatidylcholine, hydrogenated (Soy) (HSPC) phospholipidic bilayers, with respect to biomimicry and functionality. PAA is a poly(carboxylic acid) molecule, classified as a pH-sensitive polymer, whose pH-sensitivity is attributed to its regulative -COOH groups, which are protonated under acidic pH (pKa ∼4.2). Our concern was to fully characterize, in a biophysical and thermodynamical manner, the mixed nanoassemblies arising from the combination of the two biomaterials. At first, we quantified the physicochemical characteristics and physical stability of the prepared chimeric nanosystems. Then, we studied their thermotropic behavior, through measurement of thermodynamical parameters, using Differential Scanning Calorimetry (DSC). Finally, the loading and release of indomethacin (IND) were evaluated, as well as the physicochemical properties and stability of the nanocarriers incorporating it. As expected, thermodynamical findings are in line with physicochemical results and also explain the loading and release profiles of IND. The novelty of this investigation is the utilization of these pH-sensitive chimeric advanced Drug Delivery nano Systems (aDDnSs) in targeted drug delivery which relies entirely on the biophysics and thermodynamics between such designs and the physiological membranes and environment of living organisms.

  11. 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

  12. Synthesis of hollow silver spheres using poly-(styrene-methyl acrylic acid) as templates in the presence of sodium polyacrylate

    NASA Astrophysics Data System (ADS)

    Wang, Aili; Yin, Hengbo; Ge, Chen; Ren, Min; Liu, Yumin; Jiang, Tingshun

    2010-02-01

    Hollow silver spheres were successfully prepared by reducing AgNO 3 with ascorbic acid and using negatively charged poly-(styrene-methyl acrylic acid) (PSA) spheres as templates in the presence of sodium polyacrylate as a stabilizer. Firstly, silver cations adsorbed on the surface of PSA spheres via electrostatic attraction between the carboxyl groups and silver cations were reduced in situ by ascorbic acid. The silver nanoparticles deposited on the surface of PSA spheres served as seeds for the further growth of silver shells. After that, extra amount of AgNO 3 and ascorbic acid solutions were added to form PSA/Ag composites with thick silver shells. In order to obtain compact silver shells, the as-prepared PSA/Ag composites were heated at 150 °C for 3 h. Then hollow silver spheres were prepared by dissolving PSA templates with tetrahydrofuran.

  13. 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

    2013-05-07

    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.

  14. Synthesis and characterization of membranes obtained by graft copolymerization of 2-hydroxyethyl methacrylate and acrylic acid onto chitosan.

    PubMed

    dos Santos, K S C R; Coelho, J F J; Ferreira, P; Pinto, I; Lorenzetti, S G; Ferreira, E I; Higa, O Z; Gil, M H

    2006-03-09

    Chitosan based membranes to be applied on wound healing as topical drug delivery systems were developed by graft copolymerization of acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) onto chitosan using cerium ammonium nitrate as chemical initiator. Evidence for graft copolymerization of the vinyl monomers onto chitosan was obtained by FTIR and DMTA. Swelling degree, cytotoxicity, thrombogenicity and haemolytic activity of these membranes were evaluated. Chitosan-graft-AA-graft-HEMA showed to be the best matrix for drug delivery systems than chitosan-graft-AA because it retains good swelling properties, but the content in HEMA has improved cytocompatibility, hemocompatibility and thrombogenic character.

  15. Microfiltration membranes prepared from polyethersulfone powder grafted with acrylic acid by simultaneous irradiation and their pH dependence

    NASA Astrophysics Data System (ADS)

    Deng, Bo; Li, Jingye; Hou, Zhengchi; Yao, Side; Shi, Liuqing; Liang, Guoming; Sheng, Kanglong

    2008-07-01

    Polyethersulfone (PES) powder was grafted with acrylic acid (AAc) by simultaneous γ-ray irradiation. The kinetics of the radiation induced graft polymerization was studied and the grafted PES powder was characterized. Then, microfiltration (MF) membranes were prepared from PES-g-PAAc powder with different degrees of grafting (DG) under phase inversion method. The swelling behavior and the mean pore size of MF membranes were measured, and the filtration property was tested. The results showed that the pore size and the flux of MF membranes increased with the increase in DG. And, MF membranes' properties were dependent on the pH value.

  16. Chemically Cross-Linked Poly(acrylic-co-vinylsulfonic) Acid Hydrogel for the Delivery of Isosorbide Mononitrate

    PubMed Central

    Ansari, Mahvash; Khan, Ikram Ullah

    2013-01-01

    We report synthesis, characterization, and drug release attributes of a series of novel pH-sensitive poly(acrylic-co-vinylsulfonic) acid hydrogels. These hydrogels were prepared by employing free radical polymerization using ethylene glycol dimethacrylate (EGDMA) and benzyl peroxide (BPO) as cross-linker and initiator, respectively. Effect of acrylic acid (AA), polyvinylsulfonic acid (PVSA), and EGDMA on prepared hydrogels was investigated. All formulations showed higher swelling at high pHs and vice versa. Formulations containing higher content of AA and EGDMA show reduced swelling, but one with higher content of PVSA showed increased swelling. Hydrogel network was characterized by determining structural parameters and loaded with isosorbide mononitrate. FTIR confirmed absence of drug polymer interaction while DSC and TGA demonstrated molecular dispersion of drug in a thermally stable polymeric network. All the hydrogel formulations exhibited a pH dependent release of isosorbide mononitrate which was found to be directly proportional to pH of the medium and PVSA content and inversely proportional to the AA contents. Drug release data were fitted to various kinetics models. Results indicated that release of isosorbide mononitrate from poly(AA-co-VSA) hydrogels was non-Fickian and that the mechanism was diffusion-controlled. PMID:24250265

  17. Synthesis and characterization of crystalline assembly of poly(N-isopropylacrylamide)-co-acrylic acid nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhou, Bo

    In this study, crystalline poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAm-co-AAc) nanoparticle network in organic solvents was obtained by self assembling precursor particles in acetone/epichlorohydrin mixture at room temperature followed by inter-sphere crosslinking at ˜98°C. The crystals thus formed can endure solvent exchanges or large distortions under a temporary compressing force with the reoccurrence of crystalline structures. In acetone, the crystals were stable, independent of temperature, while in water crystals could change their colors upon heating or changing pH values. By passing a focused white light beam through the crystals, different colors were displayed at different observation angles, indicating typical Bragg diffraction. Shear moduli of the gel nanoparticle crystals were measured in the linear stress-yield ranges for the same gel crystals in both acetone and water. Syntheses of particles of different sizes and the relationship between particle size and the color of the gel nanoparticle networks at a constant solid content were also presented. Temperature- and pH-sensitive crystalline PNIPAm-co-AAc hydrogel was prepared using osmosis crosslinking method. Not only the typical Bragg diffraction phenomenon was observed for the hydrogel but also apparent temperature- and pH-sensitive properties were performed. The phase behavior of PNIPAm nanoparticles dispersed in water was also investigated using a thermodynamic perturbation theory combined with lightscattering and spectrometer measurements. It was shown how the volume transition of PNIPAM particles affected the interaction potential and determined a novel phase diagram that had not been observed in conventional colloids. Because both particle size and attractive potential depended on temperature, PNIPAM aqueous dispersion exhibited phase transitions at a fixed particle number density by either increasing or decreasing temperature. The phase transition of PNIPAm-co-AAc colloids was also

  18. Understanding field variation, quantum chemical modeling and molecular orbital analyses of trans-3-(trans-4-imidazolyl) acrylic acid

    NASA Astrophysics Data System (ADS)

    Gayathri, R.; Arivazhagan, M.

    2017-02-01

    In this work, a joint experimental (FTIR and FT-Raman) and theoretical (DFT and ab-initio) study on the structure and the vibrations of Trans-3-(trans-4-imidazolyl) acrylic acid (TTIAA) are compared and analyzed. The assignment of each normal mode has been made using the observed and calculated frequencies. The optimized geometries, harmonic vibrational wavenumbers and intensities of vibrational bands of trans-3-(trans-4-imidazolyl) acrylic acid (TTIAA) have been carried out using the HF/B3LYP method using the standard 6311++G(d,p) basis set calculations in this investigation. The result describes the variation in electrostatic and transport properties for zero and various external applied field. The variation in MPA charges are small due to the application of EFs: however, in most cases it is found to be systematic and almost uniform. When the field increases from 0.00 to 0.02 VÅ-1, the hybridization of molecular levels broadens the DOS and decreases the HLG from 3.6609 to 1.2325 eV; the decrease of band gap at the high field indicates that this molecule exhibit considerable electrical conductivity. Fukui indices to determine the local reactive site for the molecular systems during electrophilic, nucleophilic, radical and dual descriptor attacks. The results clearly show the superiority of MPA scheme. This study may be useful to design new molecules with more electrical conductivity.

  19. 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.

  20. Enhanced adsorption of Methylene Blue from aqueous solution by chitosan-g-poly (acrylic acid)/vermiculite hydrogel composites.

    PubMed

    Liu, Yi; Zheng, Yian; Wang, Aiqin

    2010-01-01

    A series of chitosan-g-poly (acrylic acid)/vermiculite hydrogel composites were synthesized and used as adsorbents for the investigation of the effect of process parameters such as vermiculite content, pH of dye solution, contact time, initial concentration of dye solution, temperature, ionic strength and concentration of surfactant sodium dodecyl sulfate on the removal of Methylene Blue (MB) from aqueous solution. The results showed that the adsorption capacity for dye increased with increasing pH, contact time and initial dye concentration, but decreased with increasing temperature, ionic strength and sodium dodecyl sulfate concentration in the present of the surfactant. The adsorption kinetics of MB onto the hydrogel composite followed pseudo second-order kinetics and the adsorption equilibrium data obeyed Langmuir isotherm. By introducing 10 wt.% vermiculite into chitosan-g-poly (acrylic acid) polymeric network, the obtaining hydrogel composite showed the highest adsorption capacity for MB, and then could be regarded as a potential adsorbent for cationic dye removal in a wastewater treatment process.

  1. 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...

  2. 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; ...

    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

  3. Design of a novel crosslinked HEC-PAA porous hydrogel composite for dissolution rate and solubility enhancement of efavirenz.

    PubMed

    Mabrouk, M; Chejara, D R; Mulla, J A S; Badhe, R V; Choonara, Y E; Kumar, P; du Toit, L C; Pillay, V

    2015-07-25

    The purpose of this research was to synthesize, characterize and evaluate a Crosslinked Hydrogel Composite (CHC) as a new carrier for improving the solubility of the anti-HIV drug, efavirenz. The CHC was prepared by physical blending of hydroxyethylcellulose (HEC) with poly(acrylic acid) (PAA) (1:1) in the presence of poly(vinyl alcohol) (PVA) (as a crosslinker) (1:5) under lyophilization. Efavirenz was loaded in situ into the CHC in varying proportions (200-600 mg). The CHC demonstrated impressive rheological properties (dynamic viscosity=6053 mPa; 500 s(-1)) and tensile strength (2.5 mPa) compared with the native polymers (HEC and PAA). The physicochemical and thermal behavior also confirmed that the CHC was compatible with efavirenz. The incorporation of efavirenz in the CHC increased the surface area (4.4489-8.4948 m(2)/g) and pore volume (469.547-776.916Å) of the hydrogel system which was confirmed by SEM imagery and BET surface area measurements. The solubility of efavirenz was significantly enhanced (150 times) in a sustained release manner over 24h as affirmed by the in vitro drug release studies. The hydration medium provided by the CHC network played a pivotal role in improving the efavirenz solubility via increasing hydrogen bonding as proved by the zeta potential measurements (-18.0 to +0.10). The CHC may be a promising alternative as an oral formulation for the delivery of efavirenz with enhanced solubility.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Preparation of poly(polyethylene glycol methacrylate-co-acrylic acid) hydrogels by radiation and their physical properties

    NASA Astrophysics Data System (ADS)

    Park, Sung-Eun; Nho, Young-Chang; Kim, Hyung-Il

    2004-02-01

    The pH-responsive copolymer hydrogels were prepared with the monomers of polyethylene glycol methacrylate and acrylic acid based on γ-ray irradiation technique. The gel content of these copolymer hydrogels varied depending on both the composition of monomers and the radiation dose. Maximum gel percent and degree of crosslinking were obtained at the composition of equal amount of comonomers. These copolymer hydrogels did not show any noticeable change in swelling at lower pH range. However they showed an abrupt increase in swelling at higher pH range due to the ionization of carboxyl groups. This pH-responsive swelling behavior was applied for the insulin carrier via oral delivery. Insulin-loaded copolymer hydrogels released most of their insulin in the simulated intestinal fluid which had a pH of 6.8 but not in the simulated gastric fluid which had a pH of 1.2.

  10. In Vitro Antibacterial Activity of Nano Silver Ion Substituted Poly Acrylic Acid Films on Titanium by Plasma Polymerization.

    PubMed

    Ko, Yeong-Mu; Myung, Sung-Woon; Kook, Joong-Ki; Jung, Sang-Chul; Kim, Byung-Hoon

    2015-01-01

    Antibacterial activity of oral pathogens such as Streptococcus mutans, Streptococcus sobrinus when silver ion immobilized on commercially pure (CP) titanium (Ti) surface was investigated in this study. Plasma-polymerized acrylic acid to have carboxyl group was deposited on CP-Ti surface and then ion-exchanged with Ag+ ions in 0.1 N AgNO3. In anti-adherent experiment, antibacterial activity was tested using broth culture methods. The biofilm formation assay was performed using semi-defined biofilm medium with sucrose. The silver coated CP-Ti completely inhibited the growth of S. mutans and S. sobrinus. In addition, the biofilm formation was significantly inhibited in silver-coated CP-Ti group.

  11. 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.

  12. Dispersion of alumina-coated TiO2 slurries in the presence of poly(acrylic) acid influence of monovalent counterions.

    PubMed

    Boisvert, Jean-Philippe; Malgat, Alexandre

    2005-01-15

    The rheological behavior of concentrated alumina-coated TiO2 slurries has been investigated in connection with the type of surface counterions (monovalent cations: X = Li+, Na+, TMA+) in the absence and in the presence of polyacrylic acid (PAA). The study has been conducted in a pH range of 4-10 and with ionic strengths lower than 0.01 M. The pH and ionic strength were adjusted with XOH and XCl, respectively. The surface properties have been investigated by titration of surface counterions and the apparent yield stress has been measured using a dynamic stress rheometer. It appears from the results that the pH at the maximum yield stress and the magnitude of the yield stress depend on the nature of the counterion. The yield stress measurements were also conducted in the presence of PAA (0.5 segment/nm2) adsorbed on the particle surface. In that case, the mineral surface and adsorbed polymer were neutralized with XOH. The results show that the dispersion efficiency depends on the polymer counterion. In general, it is found that the maximum yield stress and the corresponding counterion surface density both follow the sequence TMA+ < Na+ < Li+. The adsorption of PAA apparently amplifies the effects observed with the corresponding cation. An electrostriction effect of the hydration layer at the interface is suggested in order to explain the increasing yield stress as the surface density of Li+ increases. The so-called structure-making/structure-breaking model explains the yield stress reduction with the TMA+ surface density.

  13. Binding of Polycarboxylic Acids to Cationic Mixed Micelles: Effects of Polymer Counterion Binding and Polyion Charge Distribution.

    PubMed

    Yoshida; Sokhakian; Dubin

    1998-09-15

    Mixed micelles of cetyltrimethylammonium chloride (CTAC) and n-dodecyl hexaoxyethylene glycol monoether (C12E8) bind to polyanions when the mole fraction of the cationic surfactant exceeds a critical value (Yc). Yc corresponds to a critical micelle surface charge density at which polyelectrolyte will bind to this colloidal particle. Turbidimetric titrations were used to determine Yc for such cationic-nonionic micelles in the presence of acrylic acid and acrylamido-2-methylpropane sulfonate homopolymers (PAA and PAMPS, respectively) and their copolymers with acrylamide, as function of pH, ionic strength, and polyelectrolyte counterion. In 0.20 M NaCl, Yc for PAA is found to be remarkably insensitive to pH, i.e., virtually independent of the apparent polymer charge density xiapp. On the other hand, the expected inverse relationship between Yc and xiapp is observed either for PAA when NaCl is replaced by TMACl (tetramethylammonium chloride), or when xiapp is manipulated using acrylic acid/acrylamide copolymers at high pH. The effective charge density of PAA is thus seen to be suppressed by specific sodium ion binding, indicating that the influence of salts on the interaction of polycarboxylic acids with colloidal particles may differ qualitatively from their effect on the analogous behavior of strong polyanions. Comparisons between homo- and copolymers of acrylic acid were carried out also to test the hypothesis that the "mobility" of charges on PAA at moderate pH (degree of ionization less than unity) could make this "annealed" polymer exhibit the behavior of a more highly charged one. The results, while consistent with this expectation, were obscured by the likely effect of copolymer sequence distributions. Copyright 1998 Academic Press.

  14. 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

  15. 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.

  16. 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.

  17. Hysteretic memory in pH-response of water contact angle on poly(acrylic acid) brushes.

    PubMed

    Yadav, Vivek; Harkin, Adrienne V; Robertson, Megan L; Conrad, Jacinta C

    2016-04-21

    We investigated the pH-dependent response of flat polyacid brushes of varying length and dispersity in the extended brush regime. Our model system consisted of poly(acrylic acid) brushes, which change from hydrophobic and neutral at low pH to hydrophilic and negatively charged at high pH, synthesized on silicon substrates using a grafting-from approach at constant grafting density. We observed three trends in the pH-response: first, the dry brush thickness increased as the pH was increased for brushes above a critical length, and this effect was magnified as the dispersity increased; second, the water contact angle measured at low pH was larger for brushes of greater dispersity; and third, brushes of sufficient dispersity exhibited hysteretic memory behavior in the pH-dependence of the contact angle, in which the contact angle upon increasing and decreasing pH differed. As a consequence, the pKa of the brushes measured upon increasing pH was consistently higher than that measured upon decreasing pH. The observed pH response is consistent with proposed changes in the conformation and charge distribution of the polyelectrolyte brushes that depend on the direction of pH change and the dispersity of the brushes.

  18. Immobilization of urease by using chitosan-alginate and poly(acrylamide-co-acrylic acid)/kappa-carrageenan supports.

    PubMed

    Kara, Filiz; Demirel, Gökhan; Tümtürk, Hayrettin

    2006-08-01

    Jack bean urease (urea aminohydrolase, E.C. 3.5.1.5) was entrapped into chitosan-alginate polyelectrolyte complexes (C-A PEC) and poly(acrylamide-co-acrylic acid)/kappa-carrageenan (P(AAm-co-AA)/carrageenan) hydrogels for the potential use in immobilization of urease, not previously reported. The effects of pH, temperature, storage stability, reuse number, and thermal stability on the free and immobilized urease were examined. For the free and immobilized urease into C-A PEC and P(AAm-co-AA)/carrageenan, the optimum pH was found to be 7.5 and 8, respectively. The optimum temperature of the free and immobilized enzymes was also observed to be 55 and 60 degrees C, respectively. Michaelis-Menten constant (K(m)) values for both immobilized urease were also observed smaller than free enzyme. The storage stability values of immobilized enzyme systems were observed as 48 and 70%, respectively, after 70 days. In addition to this, it was observed that, after 20th use in 5 days, the retained activities for immobilized enzyme into C-A PEC and P(AAm-co-AA)/carrageenan matrixes were found as 55 and 89%, respectively. Thermal stability of the free urease was also increased by a result of immobilization.

  19. 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.

  20. Bacterial cellulose/acrylic acid hydrogel synthesized via electron beam irradiation: accelerated burn wound healing in an animal model.

    PubMed

    Mohamad, Najwa; Mohd Amin, Mohd Cairul Iqbal; Pandey, Manisha; Ahmad, Naveed; Rajab, Nor Fadilah

    2014-12-19

    Natural polymer-based hydrogels are of interest to health care professionals as wound dressings owing to their ability to absorb exudates and provide hydration for healing. The aims of this study were to develop and characterize bacterial cellulose/acrylic acid (BC/AA) hydrogels synthesized by electron beam irradiation and investigate its wound healing potential in an animal model. The BC/AA hydrogels were characterized by SEM, tensile strength, water absorptivity, and water vapor transmission rate (WVTR). The cytotoxicity of the hydrogels was investigated in L929 cells. Skin irritation and wound healing properties were evaluated in Sprague-Dawley rats. BC/AA hydrogels had a macroporous network structure, high swelling ratio (4000-6000% at 24h), and high WVTR (2175-2280 g/m(2)/day). The hydrogels were non-toxic in the cell viability assay. In vivo experiments indicated that hydrogels promoted faster wound-healing, enhanced epithelialization, and accelerated fibroblast proliferation compared to that in the control group. These results suggest that BC/AA hydrogels are promising materials for burn dressings.

  1. Poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid): synthesis, physico-chemical characterisation and nafcillin carrier.

    PubMed

    Zecheru, Teodora; Rotariu, Traian; Rusen, Edina; Mărculescu, Bogdan; Miculescu, Florin; Alexandrescu, Laura; Antoniac, Iulian; Stancu, Izabela-Cristina

    2010-10-01

    In the present study polymeric microbeads of poly(2-hydroxyethyl methacrylate-co-dodecyl methacrylate-co-acrylic acid) or p(HEMA-co-dDMA-co-AA) were synthesised and characterized through FT-IR and scanning electron microscopy (SEM); their swelling behavior against saline solution was explored and their in vitro cytotoxicity was evaluated. Further, in order to elucidate kinetic aspects regarding the ternary system p(HEMA-co-dDMA-co-AA), a mathematical model of the reactivity ratios of the comonomers in the terpolymer has been conceived and analyzed. An intensified tendency of AA units accumulation in the copolymer has been noticed, in spite of HEMA units, while dDMA conserves in the copolymer the fraction from the feed. Three compositions have been selected for nafcillin-loading and their in vitro release capacity was evaluated. The compositions of 80:10:10 and 75:10:15 M ratios appear suitable for further in vivo testing, in order to be used as drug delivery systems in the treatment of different osseous diseases.

  2. 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.

  3. Fabrication of magnetic macroporous chitosan-g-poly (acrylic acid) hydrogel for removal of Cd(2+) and Pb(2).

    PubMed

    Zhu, Yongfeng; Zheng, Yian; Wang, Feng; Wang, Aiqin

    2016-12-01

    A novel macroporous magnetic macroporous chitosan-g-poly (acrylic acid) hydrogel adsorbent was fabricated from the Pickering high internal emulsions template stabilized by modified Fe3O4 nanoparticles. The structure and composition of modified Fe3O4 and macroporous magnetic hydrogel were characterized by TEM, XRD, TG and SEM techniques. The characterization results suggest that the Fe3O4 nanoparticles have been modified successfully with organosilane of 3-aminopropyltrimethoxysilane (APTES), and the porous structure of the macroporous hydrogel can be tuned with the amount of stabilized particles, volume fraction of dispersed phase and the amount of the cosurfactant. Adsorption experiments indicate that the adsorption equilibrium was rapidly reached within 20min and the maximal adsorption capacities were determined to be 308.84mg/g for Cd(2+) and 695.22mg/g for Pb(2+). After five adsorption-desorption cycles, the adsorbent can retain its high adsorption capacity. The introduction of Fe3O4 is beneficial to the recycle of adsorbent after usage.

  4. Experimental study of albumin and lysozyme adsorption onto acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) surfaces.

    PubMed

    Moradi, Omid; Modarress, Hamid; Noroozi, Mehdi

    2004-03-01

    Many commercial soft contact lenses are based on poly-2-hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) hydrogels. The adsorption of proteins, albumin and lysozyme, on such contact lens surfaces may cause problems in their applications. In this work the adsorption of proteins, albumin and lysozyme, on hydrogel surfaces, AA and HEMA, was investigated as a function of concentration of protein. Also the effects of pH and ionic strength of protein solution on the adsorption of protein were examined. The obtained results indicated that the degree of adsorption of protein increased with the concentration of protein, and the adsorption of albumin on HEMA surface at the studied pHs (6.2-8.6) was higher than AA surface, whereas the adsorption of lysozyme on AA surface at the same pHs was higher than HEMA. The change in ionic strength of protein solution affected the proteins adsorption on both AA and HEMA surfaces. Also, the amount of sodium ions deposited on the AA surface was much higher than HEMA surface. This effect can be related to the negative surface charge of AA and its higher tendency for adsorption of sodium ions compared to the HEMA surface.

  5. 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

  6. 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.

  7. 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

    2015-12-05

    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.

  8. 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.

  9. Low-temperature preparation of highly conductive thin films from acrylic acid-stabilized silver nanoparticles prepared through ligand exchange.

    PubMed

    Vo, Duc Quy; Shin, Eun Woo; Kim, Jae-Seong; Kim, Sunwook

    2010-11-16

    The preparation of AcA-stabilized Ag nanoparticles and its application to make highly conductive thin films are reported. The AcA-stabilized Ag nanoparticles were prepared through a ligand exchange of original oleylamine (OLA)-coated Ag nanoparticles with acrylic acid (AcA), which acted as both an antisolvent and a modifying ligand during the ligand exchange process. Efficiencies of the ligand exchange as well as the properties of Ag nanoparticles were analyzed using various techniques including TEM, FT-IR, XPS, TGA, and UV-vis methods. The thin films were fabricated by annealing spin-coated AcA-stabilized Ag nanoparticles. Further, the effects of annealing temperature, time, and film thickness on both the film morphology and electrical conductivity have been investigated. In this work, due to the low boiling temperature of stabilizer (AcA) and adjustment of annealing conditions, high electrical conductivity was obtained for the Ag thin films. For example, when annealing at 175 °C for 30 min, a 70 nm thick film showed a maximum electrical conductivity of 1.12 × 10(5) S cm(-1). A conductive layer on a flexible polymer substrate (e.g., PET) sheet has been successfully prepared by annealing a spin-coated film at 140 °C for 30 min. The combined advantages of long-term stability of the AcA-stabilized Ag nanoparticles, low annealing temperature, and high conductivity of the prepared thin films make this relatively simple method attractive for applications in flexible electronics.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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

  16. Efficient enzymatic acrylation through transesterification at controlled water activity.

    PubMed

    Nordblad, Mathias; Adlercreutz, Patrick

    2008-04-15

    Enzymatic acrylation is a process of potentially strong interest to the chemical industry. Direct esterification involving acrylic acid is unfortunately rather slow, with inhibition phenomena appearing at high acid concentrations. In the present study the acrylation of 1-octanol catalyzed by immobilized Candida antarctica lipase B (Novozym 435) was shown to be as much as an order of magnitude faster when ethyl acrylate served as the donor of the acrylic group. Water activity is a key parameter for optimizing the rate of ester synthesis. The optimum water activity for the esterification of octanol by acrylic acid was found to be 0.75, that for its esterification by propionic acid to be 0.45 and the transesterification involving ethyl acrylate to be fastest at a water activity of 0.3. The reasons for these differences in optimum water activity are discussed in terms of enzyme specificity, substrate solvation, and mass transfer effects.

  17. 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.

  18. 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

  19. The dual temperature/pH-sensitive multiphase behavior of poly(N-isopropylacrylamide-co-acrylic acid) microgels for potential application in in situ gelling system.

    PubMed

    Xiong, Wei; Gao, Xiang; Zhao, Yanbing; Xu, Huibi; Yang, Xiangliang

    2011-05-01

    Poly(N-isopropylacrylamide-co-acrylic acid) microgels (PNA) may be an excellent formulation for in situ gelling system due to their high sensitivity and fast response rate. Four monodispersed PNA microgels with various contents of acrylic acid (AA) were synthesized by emulsion polymerization in this paper. Their hydrodynamic diameters decreased reversibly with both decreasing pH and increasing temperature. The dual temperature/pH-sensitivity was influenced by many factors such as AA content, cross-link density and ion strength. In addition, high concentration PNA dispersions underwent multiple phase transition according to different temperatures, pHs and concentrations, which were summarized in a 3D sol-gel phase diagram in this study. According to the sol-gel phase transition, 8% PNA-025 dispersion maintained a relatively low viscosity and favorable fluidity at pH 5.0 in the temperature range of 25-40°C, but it rapidly increased in viscosity at pH 7.4 and gelled at 37°C. This feature enabled the dual temperature/pH-sensitive microgels to overcome the troubles in syringing of temperature sensitive materials during the injection. Apart from this, PNA could form gel well in in vitro (e.g., medium and serum) and in in vivo with low cytotoxicity. Therefore, it is promising for PNA to be applied in the in situ gelling system.

  20. Iron-Based Redox Polymerization of Acrylic Acid for Direct Synthesis of Hydrogel/Membranes, and Metal Nanoparticles for Water Treatment.

    PubMed

    Hernández, Sebastián; Papp, Joseph K; Bhattacharyya, Dibakar

    2014-01-22

    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.

  1. 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.

  2. 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.

  3. Separation of poly(acrylic acid) salts according to topology using capillary electrophoresis in the critical conditions.

    PubMed

    Maniego, Alison R; Ang, Dale; Guillaneuf, Yohann; Lefay, Catherine; Gigmes, Didier; Aldrich-Wright, Janice R; Gaborieau, Marianne; Castignolles, Patrice

    2013-11-01

    Branching was detected in polyacrylates synthesised through radical polymerization via solution-state NMR, while inconsistencies have been reported for the determination of the molar mass of hydrophilic polyacrylates using aqueous-phase and organic-phase size-exclusion chromatography. In this work, poly(sodium acrylate)s, PNaAs, of various topologies were separated for the first time using free-solution capillary electrophoresis (CE). Free-solution CE does not separate the PNaAs by their molar mass, similarly to separations by liquid chromatography in the critical conditions, rather by different topologies (linear, star branched, and hyperbranched). The electrophoretic mobility of PNaAs increases as the degree of branching decreases. Separation is shown to be not only by the topology but also by the end groups as expected for a separation in the critical conditions: replacing a relatively bulky nitroxide end group with hydrogen atom yielded a higher electrophoretic mobility. This novel method, capillary electrophoresis in the critical conditions enabled, for the first time, the separation of hydrophilic polyacrylates according to their topology (branching) and their chain ends. This will allow meaningful and accurate characterization of their branched topologies as well as molar masses and progress in for advanced applications such as drug delivery or flocculation.

  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. Preparation and in vitro release studies of ibuprofen-loaded films and microspheres made from graft copolymers of poly(L-lactic acid) on acrylic backbones.

    PubMed

    Gallardo, A; Eguiburu, J L; Fernandez Berridi, M J; San Román, J

    1998-11-13

    The present article describes the preparation of films of various thickness and microspheres from new resorbable graft copolymers of polyacrylic (methyl methacrylate, MMA, or methyl acrylate, MA), or polyvinylic (vinyl pyrrolidone, VP) chains and poly(l-lactic acid) (PLLA) side blocks charged with 15-20% of ibuprofen (IBU) (a non-steroidic antiinflammatory agent). In the case of MMA-LLA and MA-LLA graft copolymers the release of IBU in buffered solution is modulated by the flexibility of the copolymer chains in a first step of one to two days and in a second step by the diffusive properties of the system as well as by the biodegradation of the polymers. The VP-PLLA graft copolymers are highly hydrophilic and the release of IBU is modulated by the diffusion of the drug through the swollen system. Specific interactions between the IBU molecules and the pyrrolidone rings also participate in the kinetic behaviour of the release process.

  6. 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

    2009-06-03

    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.

  7. Hybrid polymeric hydrogels for ocular drug delivery: nanoparticulate systems from copolymers of acrylic acid-functionalized chitosan and N-isopropylacrylamide or 2-hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    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.

  8. Fe2O3/TiO2 nanocomposite photocatalyst prepared by supercritical fluid combination technique and its application in degradation of acrylic acid

    NASA Astrophysics Data System (ADS)

    Wei, J.; Zhang, J. C.

    2017-01-01

    Fe2O3/TiO2 nanocomposite photocatalysts were synthesized by supercritical fluid combination technique, consisting of sol-gel method and supercritical fluid drying. The photocatalytic activity of the samples was evaluated by the degradation of acrylic acid. The results indicated that the Fe2O3/TiO2 nanocomposite catalysts prepared by this novel technique showed significant improvement in catalytic activity compared with pure TiO2 or Fe2O3/TiO2 catalysts prepared by traditional drying. Both infrared and ultraviolet spectrum of Fe2O3/TiO2 nanocomposite photocatalysts shift a little to lower wavelength indicating that the absorption threshold of Fe doped nanocomposite photocatalysts shift into the visible light region. This phenomenon was also attested by the photocatalytic degradation test under visible light.

  9. 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.

  10. Thiolated polymers: self-crosslinking properties of thiolated 450 kDa poly(acrylic acid) and their influence on mucoadhesion.

    PubMed

    Marschütz, Michaela K; Bernkop-Schnürch, Andreas

    2002-05-01

    This study examined the rheological and mucoadhesive properties of a self-crosslinking anionic thiolated polymer in vitro. Mediated by a carbodiimide, L-cysteine was covalently bound to poly(acrylic acid) of 450 kDa molecular mass. The resulting thiolated polymers (conjugates I and II) contained 90.5+/-15.8 and 511.6+/-52 micromol thiol groups per gram polymer, respectively (mean+/-S.D., n=3). The amount of covalently attached cysteine was therefore dependent on the concentration of carbodiimide used for the coupling reaction. Both conjugates (3%, m/v) were capable of forming inter- and/or intramolecular disulfide bonds in 100 mM phosphate buffer pH 6.8. Consequently, the apparent viscosity of conjugates I and II increased 12- and 10-fold, respectively, within 24 h of incubation at 37 degrees C. Further, rheological synergy was observed by mixing equal volumes of polymer (unmodified as well as modified) with a mucin solution. A six-fold increase in viscosity immediately after mixing could be observed for the conjugate II/mucin mixture. This clearly indicates the high interaction potential of self-crosslinking thiomers with the mucus gel layer. Mucoadhesion studies confirmed the rheological results. Tablets based on conjugate II remained attached on freshly excised porcine mucosa for about 25 times longer than the corresponding controls, which is the longest time of mucoadhesion ever found among anionic thiomers. Due to the results of the present study, self-crosslinking thiolated poly(acrylates) of 450 kDa represent very promising excipients for the development of various mucoadhesive drug delivery systems.

  11. 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

  12. 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.

  13. 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...

  14. 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.

  15. Swelling and aspirin release study: cross-linked pH-sensitive vinyl acetate-co-acrylic acid (VAC-co-AA) hydrogels.

    PubMed

    Ranjha, Nazar Mohammad; Mudassir, Jahanzeb

    2008-05-01

    The objective of this work was to develop new pH-sensitive hydrogels to deliver gastric mucosal irritating drugs to the lower part of the gastrointestinal tract. For this purpose, cross-linked vinyl acetate-co-acrylic acid (VAC-co-AA) hydrogels were synthesized by using N, N, methylene bisacrylamide (MBAAm) as a cross-linking agent. Different ratios of 90:10, 70:30, 50:50, 30:70, and 10:90 of VAC-co-AA were synthesized. All of the compositions were cross-linked using 0.15, 0.30, 0.45, and 0.60 mol percent MBAAm. Swelling and aspirin release were studied for 8 hour period. The drug release data were fitted into various kinetic models like the zero-order, first-order, Higuchi, and Peppas. Hydrogels were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. In addition to the above, these hydrogels were loaded with 2%, 8% and 14% w/v aspirin solutions, keeping the monomeric composition and degree of cross-linking constant. In conclusion, it can be said that aspirin can be successfully incorporated into cross-linked VAC/AA hydrogels and its swelling and drug release can be modulated by changing the mole fraction of the acid component in the gels.

  16. 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.

  17. 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).

  18. 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.

  19. Competitive sorption of Pb(II) and Zn(II) on polyacrylic acid-coated hydrated aluminum-oxide surfaces.

    PubMed

    Wang, Yingge; Michel, F Marc; Levard, Clement; Choi, Yong; Eng, Peter J; Brown, Gordon E

    2013-01-01

    Natural organic matter (NOM) often forms coatings on minerals. Such coatings are expected to affect metal-ion sorption due to abundant sorption sites in NOM and potential modifications to mineral surfaces, but such effects are poorly understood in complex multicomponent systems. Using poly(acrylic acid) (PAA), a simplified analog of NOM containing only carboxylic groups, Pb(II) and Zn(II) partitioning between PAA coatings and α-Al2O3 (1-102) and (0001) surfaces was investigated using long-period X-ray standing wave-florescence yield spectroscopy. In the single-metal-ion systems, PAA was the dominant sink for Pb(II) and Zn(II) for α-Al2O3(1-102) (63% and 69%, respectively, at 0.5 μM metal ions and pH 6.0). In equi-molar mixed-Pb(II)-Zn(II) systems, partitioning of both ions onto α-Al2O3(1-102) decreased compared with the single-metal-ion systems; however, Zn(II) decreased Pb(II) sorption to a greater extent than vice versa, suggesting that Zn(II) outcompeted Pb(II) for α-Al2O3(1-102) sorption sites. In contrast, >99% of both metal ions sorbed to PAA when equi-molar Pb(II) and Zn(II) were added simultaneously to PAA/α-Al2O3(0001). PAA outcompeted both α-Al2O3 surfaces for metal sorption but did not alter their intrinsic order of reactivity. This study suggests that single-metal-ion sorption results cannot be used to predict multimetal-ion sorption at NOM/metal-oxide interfaces when NOM is dominated by carboxylic groups.

  20. Silicone/Acrylate Copolymers

    NASA Technical Reports Server (NTRS)

    Dennis, W. E.

    1982-01-01

    Two-step process forms silicone/acrylate copolymers. Resulting acrylate functional fluid is reacted with other ingredients to produce copolymer. Films of polymer were formed by simply pouring or spraying mixture and allowing solvent to evaporate. Films showed good weatherability. Durable, clear polymer films protect photovoltaic cells.

  1. 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

    2014-05-06

    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.

  2. Conducting polymer films fabricated by oxidative graft copolymerization of aniline on poly(acrylic acid) grafted poly(ethylene terephthalate) surfaces.

    PubMed

    Wang, Jiku; Liu, Xuyan; Choi, Ho-Suk; Kim, Jong-Hoon

    2008-11-27

    A conductive polyaniline/poly(ethylene terephthalate) (PANI/PET) composite film was fabricated via the oxidative graft copolymerization of aniline (ANI) onto the plasma-induced poly(acrylic acid) (PAAc) grafted PET surface. The attenuated total reflectance Fourier transform infrared spectroscopy spectra (ATR-FTIR) and X-ray photoelectron spectroscopy (XPS) results confirmed that PANI was successfully grafted onto the surface of the PAAc-g-PET films. The effects of the experimental conditions on the percentage of PANI grafted onto the PAAc-g-PET films were extensively investigated. A very high grafting percentage of ANI can be obtained through the acid-base reaction between the aniline monomer and PAAc on the PAAc-g-PET surface at high temperature. As a result, the grafting percentage of PANI can be increased to as high as 12.18 wt %, which causes the surface resistance of the PANI-g-PAAc-g-PET film to be reduced to about 1000 Omega/sq. We predicted that this is because of the high flexibility of the PAAc molecular chains and high solubility of aniline, both of which facilitate the binding of aniline to PAAc during this high temperature acid-base reaction. It was observed by atomic force microscopy (AFM) that the PANI-modified PET surface exhibits higher size irregularity and surface roughness, which further indicated that a much greater number of aniline molecules can be reactively bonded to and distributed along the grafted AAc chains and that the PANI-g-PAAc-g-PET surface resulting from the sequential oxidative graft copolymerization can possess higher electrical conductivity.

  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.

  4. 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.

  5. 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

  6. Preparation and optimization of superabsorbent hydrogel micromatrices based on poly(acrylic acid), partly sodium salt-g-poly(ethylene oxide) for modified release of indomethacin.

    PubMed

    Yuksel, Nilufer; Beba, Leyla

    2009-06-01

    The purpose of this study was to prepare modified-release dosage of indomethacin (IND) in the form of micromatrices based on a superabsorbent hydrogel (SAH), poly(acrylic acid), partly sodium salt-g-poly(ethylene oxide) (PAAc-Na-g-PEO). A soaking procedure was used for the preparation of drug-loaded hydrogel micromatrices. The amount of IND, volume of drug-loading solution, and amount of PAAc-Na-g-PEO granules used for preparing micromatrices were the independent factors. The dependent factors were the measured responses from micromatrices, that is, percent recovery, percent entrapment efficiency, and the time at which 63.2% of the drug was released (T(d), minutes). A three-factor, three-level full factorial design (33) was created to optimize formulations. Nonlinear regression analysis indicated a good correlation between the measured responses and the independent factors. Optimum responses were obtained from medium levels of IND and SAH and low level of drug-loading solution. Differential scanning calorimetry, X-ray diffraction analysis, and scanning electron micrography indicated that IND crystals are physically adsorbed into the pores and irregular spaces of the hydrogel.

  7. 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.

  8. Selective adsorption of Pb (II) ions by amylopectin-g-poly (acrylamide-co-acrylic acid): A bio-degradable graft copolymer.

    PubMed

    Sasmal, Dinabandhu; Maity, Jayanta; Kolya, Haradhan; Tripathy, Tridib

    2017-04-01

    Amylopectin-g-poly (acrylamide-co-acrylic acid) [AP-g-poly (AM-co-AA)] was synthesised in water medium by using potassium perdisulphate as an initiator. The graft copolymer was characterized by molecular weight determination by size exclusion chromatography (SEC), fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR) spectroscopy, scanning electron microscope (SEM) studies, thermal analysis, measurement of neutralisation equivalent and biodegradation studies. The graft copolymer was used for Pb (II) ion removal from aqueous solution. The Pb (II) ion removal capacity of the graft copolymer was also compared with another laboratory developed graft copolymer Amylopectin-g-poly (acrylamide) (AP-g-PAM). Both the graft copolymers were also used for the competitive metal ions removal with Pb (II)/Cd (II), Pb (II)/Zn (II), Pb (II)/Ni (II), Pb (II)/Cu (II) pairs separately under similar conditions. AP-g-poly (AM-co-AA) showed better Pb (II) ion adsorbing power over AP-g-PAM and also much selective towards Pb (II) ions. The adsorption follows a second order rate equation and Langmuir isotherm model.

  9. In situ synthesis of silver nanoparticles on the cotton fabrics modified by plasma induced vapor phase graft polymerization of acrylic acid for durable multifunction

    NASA Astrophysics Data System (ADS)

    Wang, C. X.; Ren, Y.; Lv, J. C.; Zhou, Q. Q.; Ma, Z. P.; Qi, Z. M.; Chen, J. Y.; Liu, G. L.; Gao, D. W.; Lu, Z. Q.; Zhang, W.; Jin, L. M.

    2017-02-01

    A practical and ecological method for preparing the multifunctional cotton fabrics with excellent laundering durability was explored. Cotton fabrics were modified by plasma induced vapor phase graft polymerization (PIVPGP) of acrylic acid (AA) and subsequently silver nanoparticles (AgNPs) were in situ synthesized on the treated cotton fabrics. The AgNP loaded cotton fabrics were characterized by scanning electron microscope (SEM), energy dispersive X-ray (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), antibacterial activity, self-cleaning activity, thermal stability and laundering durability, respectively. SEM observation and EDX, XPS and XRD analysis demonstrated the much more AgNPs deposition on the cotton fabrics modified by PIVPGP of AA. The AgNP loaded cotton fabrics also exhibited better antibacterial activity, self-cleaning activity, thermal stability and laundering durability. It was concluded that the surface modification of the cotton fabrics by PIVPGP of AA could increase the loading efficiency and binding fastness of AgNPs on the treated cotton fabrics, which could fabricate the cotton fabrics with durable multifunction. In addition, the mechanism of in situ synthesis of AgNPs on the cotton fabrics modified by PIVPGP of AA was proposed.

  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. Characterization and biocompatibility evaluation of bacterial cellulose-based wound dressing hydrogel: effect of electron beam irradiation doses and concentration of acrylic acid.

    PubMed

    Mohamad, Najwa; Buang, Fhataheyah; Mat Lazim, Azwan; Ahmad, Naveed; Martin, Claire; Mohd Amin, Mohd Cairul Iqbal

    2016-09-30

    The use of bacterial cellulose (BC)-based hydrogel has been gaining attention owing to its biocompatibility and biodegradability. This study was designed to investigate the effect of radiation doses and acrylic acid (AA) composition on in vitro and in vivo biocompatibility of BC/AA as wound dressing materials. Physical properties of the hydrogel, that is, thickness, adhesiveness, rate of water vapor transmission, and swelling were measured. Moreover, the effect of these parameters on skin irritation and sensitization, blood compatibility, and cytotoxicity was studied. Increased AA content and irradiation doses increased the thickness, crosslinking density, and improved the mechanical properties of the hydrogel, but reduced its adhesiveness. The swelling capacity of the hydrogel increased significantly with a decrease in the AA composition in simulated wound fluid. The water vapor permeability of polymeric hydrogels was in the range of 2035-2666 [g/(m(-2 ) day(-1) )]. Dermal irritation and sensitization test demonstrated that the hydrogel was nonirritant and nonallergic. The BC/AA hydrogel was found to be nontoxic to primary human dermal fibroblast skin cells with viability >88% and was found to be biocompatible with blood with a low hemolytic index (0.80-1.30%). Collectively, these results indicate that these hydrogels have the potential to be used as wound dressings. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2016.

  12. 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

  13. Uniform thin film electrode made of low-temperature-sinterable silver nanoparticles: optimized extent of ligand exchange from oleylamine to acrylic acid

    NASA Astrophysics Data System (ADS)

    Lee, Yung Jong; Kim, Na Rae; Lee, Changsoo; Lee, Hyuck Mo

    2017-02-01

    Lowering the sintering temperature of nanoparticles in the electrode deposition process holds both academic and industrial interest because of the potential applications of such electrodes in polymer devices and flexible electronics. In addition, achieving uniform electrode formation after ligand exchange is equally important as lowering the sintering temperature. Here, we report a simple chemical treatment by the addition of ligand-exchanging interfaces to lower the sintering temperature; we also determine the optimum extent of ligand exchange for crack-free electrode formation. First, we investigated the structural change of Ag thin films with respect to the concentration of acrylic acid (AA) solutions. Second, we used thermal analysis to evaluate the effects of changes in the sintering temperature. We observed that the resulting conductivity of the Ag patterns was only one order of magnitude lower than that of bulk Ag when the patterns were sintered at 150 °C. The simple chemical treatment developed in this work for solution-processed Ag electrode formation can be adopted for flexible electronics, which would eliminate the need for vacuum and high-temperature processes.

  14. 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.

  15. 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.

  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. Preparation and characterization of pH-sensitive and antifouling poly(vinylidene fluoride) microfiltration membranes blended with poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid).

    PubMed

    Ju, Junping; Wang, Chao; Wang, Tingmei; Wang, Qihua

    2014-11-15

    Functional terpolymer of poly(methyl methacrylate-2-hydroxyethyl methacrylate-acrylic acid) (P(MMA-HEMA-AA)) was synthesized via a radical polymerization method. The terpolymer could be directly blended with poly(vinylidene fluoride) (PVDF) to prepare the microfiltration (MF) membranes via phase separate process. The synthesized polymers were characterized by Fourier transform infrared (FTIR), the nuclear magnetic resonance proton spectra ((1)H NMR). The membrane had the typical asymmetric structure and the hydrophilic side chains tended to aggregate on the membrane surface. The surface enrichment of amphiphilic copolymer and morphology of MF membranes were characterized by Fourier transform infrared attenuated total reflection spectroscopy (FTIR-ATR) and scanning electron microscopy (SEM). The contact angle (CA) and water uptake were also tested to assess the hydrophilicity and wetting characteristics of the polymer surface. The water filtration properties were measured. It was found the modified membranes showed excellent pH-sensitivity and pH-reversibility behavior. Furthermore, the hydrophilicity of the blended membranes increased, and the membranes showed good protein antifouling property.

  18. Xylan-rich hemicelluloses-graft-acrylic acid ionic hydrogels with rapid responses to pH, salt, and organic solvents.

    PubMed

    Peng, Xin-Wen; Ren, Jun-Li; Zhong, Lin-Xin; Peng, Feng; Sun, Run-Cang

    2011-08-10

    Exploitation of biomaterials derived from renewable resources is an important approach to address environmental and resource problems in the world today. In this paper, novel ionic hydrogels based on xylan-rich hemicelluloses were prepared by free radical graft copolymerization of acrylic acid (AA) and xylan-rich hemicelluloses (XH) by using N,N-methylene-bis(acrylamide) (MBA) as cross-linker and ammonium persulfate/N,N,N',N'-tetramethylethylenediamine (APS/TMEDA) as redox initiator system. The network characteristics of the ionic hydrogels were investigated by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM), as well as by determination of mechanical properties, swelling, and stimuli responses to pH, salts, and organic solvents. The results showed that an increase in the MBA/XH or AA/XH ratio resulted in higher cross-linking density of the network and thus decreased the swelling ratio. Expansion of the network hydrogels took place at high pH, whereas shrinkage occurred at low pH or in salt solutions as well as in organic solvents. The ionic hydrogels had high water adsorption capacity and showed rapid and multiple responses to pH, ions, and organic solvents, which may allow their use in several areas such as adsorption, separation, and drug release systems.

  19. 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.

  20. Preparation and dielectric analysis of microphase-separated poly(acrylonitrile-co-acrylamide-co-acrylic acid) hydrogels

    SciTech Connect

    Hu, D.Shiaw-Guang; Lin, Yow-Shi

    1993-12-31

    The acidic hydrolysis of polyacrylonitrile was carried out to yield a variety of terpolymers made up of nitriles, amides and acids. The formation of block structure was shown to follow a ripper mechanism occurring to acrylamide groups, that is more pronounced for a certain range of acrylamide content, evidenced by the composition analysis using {sup 1}H-NMR and base titration. The rates of formation of acrylamide fraction and acid fraction in the consecutive mode are approximately the same, yielding the content of ionic groups from 0.8 to 2.2. mole percent, dependent on the time of hydrolysis. The dielectric relaxation measurement on swollen gels shows three relaxation transitions, {alpha}, {beta}, {gamma}, over -150{degrees}C to 0{degrees}C, as influenced by the chemical composition and water absorption. The {beta} and {gamma} are associated with the polymer-water interaction and short-range motion of polymers and water.

  1. 21 CFR 173.5 - Acrylate-acrylamide resins.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.5 Acrylate-acrylamide resins... and acrylic acid, with the greater part of the polymer being composed of acrylamide units. (2) Sodium... sodium silicate-sodium hydroxide aqueous solution, with the greater part of the polymer being composed...

  2. Electrochemical imprinted sensor for determination of oleanic acid based on poly (sodium 4-styrenesulfonate-co-acrylic acid)-grafted multi-walled carbon nanotubes-chitosan and cobalt hexacyanoferrate nanoparticles.

    PubMed

    Hu, Yufang; Zhang, Zhaohui; Li, Jiaxing; Zhang, Huabin; Luo, Lijuan; Yao, Shouzhuo

    2012-01-15

    A novel sensitive and selective imprinted electrochemical sensor for the determination of oleanic acid was constructed on a carbon electrode by stepwise modification of functional multi-walled carbon nanotubes, cobalt hexacyanoferrate nanoparticles and a thin imprinted sol-gel film. The fabrication of a homogeneous porous poly (sodium 4-styrenesulfonate-co-acrylic acid)-grafted multi-walled carbon nanotubes/SiO(2)-chitosan nanocomposite film was conducted by controllable electrodeposition technology. The surface morphologies of the modified electrodes were characterized by scanning electron microscope. The performance of the imprinted sensor was investigated by cyclic voltammetry, square wave voltammetry and electrochemical impedance spectroscopy in detail. The imprinted sensor displayed high sensitivity and selectivity towards oleanic acid. A linear relationship between the sensor response signal and the logarithm of oleanic acid concentrations ranging from 1.0×10(-8) to 1.0×10(-3) mol L(-1) was obtained with a detection limit of 2.0×10(-9) mol L(-1). It was applied to the determination of oleanic acid in real capsule samples successfully.

  3. 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.

  4. Comparison of acidic polymers for the removal of cobalt from water solutions by polymer assisted ultrafiltration.

    PubMed

    Dambies, Laurent; Jaworska, Agnieszka; Zakrzewska-Trznadel, Grazyna; Sartowska, Bozena

    2010-06-15

    In this study, three sulfonated water-soluble polymers based on poly(vinyl alcohol) of different molecular weights (10,000, 50,000 and 100,000 Da) were prepared and tested against commercially available poly(acrylic acid) for the removal of cobalt using polymer assisted ultrafiltration. High rejection rates were obtained between pH 3 and 6 with sulfonated poly(vinyl alcohol) (PVA 10,000 and 50,000 Da) whereas poly(acrylic acid) (PAA) of similar molecular weights performed rather poorly in this pH range. Sulfonation improved significantly sorption capability of PVA. Sulfonated PVA 10,000 was the best complexing agent with rejection rate above 95% between pH 3 and 6. For unmodified PVA the rejection rate was only 30-45% at pH 6 and there was no rejection at pH 3 at all. PAA rejection rate was above 90% at pH 6 and only about 10% at pH 3. Large scale experiment in cross-flow, continuous apparatus conducted by using PVA-SO(3)H 10,000 Da to remove (60)Co radioisotope from water solutions showed excellent results demonstrating the potential of this polymer to purify acidic radioactive wastes containing cobalt radioisotopes.

  5. 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.

  6. 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.

  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.

  8. Radiation-induced synthesis and swelling properties of p(2-hydroxyethyl methacrylate/itaconic acid/oligo (ethylene glycol) acrylate) terpolymeric hydrogels

    NASA Astrophysics Data System (ADS)

    Micic, M.; Stamenic, D.; Suljovrujic, E.

    2012-09-01

    Since it is presumed that by incorporation of pH-responsive (IA) and temperature-responsive (OEGA) co-monomers, it is possible to prepare P(HEMA/IA/OEGA) hydrogels with dual (pH and thermo) responsiveness, the main purpose of our study is to investigate the influence of different mole fractions of IA and especially OEGA on the diversity of the swelling properties of the obtained hydrogels. For that reason, a series of terpolymeric hydrogels with different mole ratios of 2-hydroxyethyl methacrylate (HEMA), itaconic acid (IA) and oligo(ethylene glycol) acrylates (OEGA) was synthesised by gamma radiation. The obtained hydrogels were characterised by swelling studies in the wide pH (2.2-9.0) and temperature range (20-70 °C), confirming dual (pH and thermo) responsiveness and a large variation in the swelling capability. It was observed that the equilibrium swelling of P(HEMA/IA/OEGA) hydrogels, for a constant amount of IA, increased progressively with an increase in OEGA share. On the other hand, the dissociation of carboxyl groups from IA occurs at pH>4; therefore, small mole fractions of IA render good pH sensitivity and a large increase in the swelling capacity of these hydrogels at higher pH values. Additional characterisation of structure and properties was conducted by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM) and mechanical measurements, confirming that the inherent properties of P(HEMA/IA/OEGA) hydrogels can be significantly tuned by variation in their composition. According to all presented, it seems that the obtained hydrogels can be a beneficial synergetic combination for controlled delivery of bioactive molecules such as drugs, peptides, proteins, etc.

  9. Poly (N-isopropylacrylamide)-co-(acrylic acid) microgel/Ag nanoparticle hybrids for the colorimetric sensing of H2O2.

    PubMed

    Han, De-Man; Zhang, Qiang Matthew; Serpe, Michael J

    2015-02-14

    Poly (N-isopropylacrylamide)-co-(acrylic acid) (pNIPAm-co-AAc) microgels composed of Ag nanoparticles (Ag NPs) have been synthesized and employed for the colorimetric sensing of H2O2. Each pNIPAm-co-AAc microgel, which exhibited a diameter of ∼800 nm, contained multiple Ag NPs (diameter of ∼5 nm), and solutions of these hybrid materials showed a UV-vis absorption band at ∼400 nm. This is due to the excitation of the Ag NP surface plasmon. We go on to show that the intensity of this absorption band is dependent on the concentration of H2O2 in solution. Specifically, in the presence of H2O2 the magnitude of the absorption peak dramatically decreases in a linear fashion over the concentration range of 0.30 to 3.00 μM H2O2 (r(2) = 0.9918). We go on to show that the response is selective for H2O2 and can still function in complex mixtures, e.g., we showed that the response is still robust in milk samples. While Ag NPs themselves can exhibit similar responses, this system has many benefits including sample processing and long term stability - i.e., Ag NPs are destabilized in solutions of a certain pH, and aggregate readily. Our microgel/Ag NP hybrids have been shown to be extremely stable and are easily purified prior to use by simple centrifugation/washing protocols. This system is simple and straightforward to use, is low cost, and can be used in complex media, which makes it practical for analyzing complex biological and environmental samples.

  10. 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.

  11. Rapid removal of copper with magnetic poly-acrylic weak acid resin: quantitative role of bead radius on ion exchange.

    PubMed

    Fu, Lichun; Shuang, Chendong; Liu, Fuqiang; Li, Aimin; Li, Yan; Zhou, Yang; Song, Haiou

    2014-05-15

    A novel magnetic weak acid resin NDMC was self-synthesized for the removal of Cu(2+) from aqueous solutions. NDMC showed superior properties on the removal of Cu(2+) compared to commercial resins C106 and IRC-748, which was deeply investigated by adsorption isotherms and kinetic tests. The equilibrium adsorption amount of Cu(2+) onto NDMC (267.2mg/g) was almost twice as large as that onto IRC-748 (120.0mg/g). The adsorption kinetics of Cu(2+) onto the three resins fitted well with the pseudo-second-order equation. The initial adsorption rate h of NDMC was about 4 times that of C106 and nearly 8 times that of IRC-748 at the initial concentration of 500mg/L. External surface area was determined to be the key factor in rate-controlling by further analyzing the adsorption thermodynamics, kinetics parameters and physicochemical properties of the resins. NDMC resin with the smallest bead radius possessed the largest external surface and therefore exhibited the fastest kinetics. The adsorption amount of Cu(2+) onto NDMC was not influenced as the concentration of Na(+) increased from 1.0 to 10.0mM/L. Dilute HCl solution could effectively desorb Cu(2+). NDMC demonstrated high stability during 10 adsorption/desorption cycles, showing great potential in the rapid removal of Cu(2+) from wastewater.

  12. Surface functionalisation of polypropylene hernia-repair meshes by RF-activated plasma polymerisation of acrylic acid and silver nanoparticles

    NASA Astrophysics Data System (ADS)

    Nisticò, Roberto; Rosellini, Andrea; Rivolo, Paola; Faga, Maria Giulia; Lamberti, Roberta; Martorana, Selanna; Castellino, Micaela; Virga, Alessandro; Mandracci, Pietro; Malandrino, Mery; Magnacca, Giuliana

    2015-02-01

    Hernia diseases are among the most common and diffuse causes of surgical interventions. Unfortunately, still nowadays there are different phenomena which can cause the hernioplasty failure, for instance post-operative prostheses displacements and proliferation of bacteria in the surgical site. In order to limit these problems, commercial polypropylene (PP) and polypropylene/Teflon (PP/PTFE) bi-material meshes were surface functionalised to confer adhesive properties (and therefore reduce undesired displacements) using polyacrylic acid synthesized by plasma polymerisation (PPAA). A broad physico-chemical and morphological characterisation was carried out and adhesion properties were investigated by means of atomic force microscopy (AFM) used in force/distance (F/D) mode. Once biomedical devices surface was functionalised by PPAA coating, metallic silver nanoparticles (AgNPs) with antimicrobial properties were synthesised and loaded onto the polymeric prostheses. The effect of the PPAA, containing carboxylic functionalities, adhesive coating towards AgNPs loading capacity was verified by means of X-ray photoelectron spectroscopy (XPS). Preliminary measurement of the Ag loaded amount and release in water were also investigated via inductively coupled plasma atomic emission spectroscopy (ICP-AES). Promising results were obtained for the functionalised biomaterials, encouraging future in vitro and in vivo tests.

  13. 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...

  14. 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.

  15. Physically Cross-linked Polymer Binder Induced by Reversible Acid-Base Interaction for High-Performance Silicon Composite Anodes.

    PubMed

    Lim, Sanghyun; Chu, Hodong; Lee, Kukjoo; Yim, Taeeun; Kim, Young-Jun; Mun, Junyoung; Kim, Tae-Hyun

    2015-10-28

    Silicon is greatly promising for high-capacity anode materials in lithium-ion batteries (LIBs) due to their exceptionally high theoretical capacity. However, it has a big challenge of severe volume changes during charge and discharge, resulting in substantial deterioration of the electrode and restricting its practical application. This conflict requires a novel binder system enabling reliable cyclability to hold silicon particles without severe disintegration of the electrode. Here, a physically cross-linked polymer binder induced by reversible acid-base interaction is reported for high performance silicon-anodes. Chemical cross-linking of polymer binders, mainly based on acidic polymers including poly(acrylic acid) (PAA), have been suggested as effective ways to accommodate the volume expansion of Si-based electrodes. Unlike the common chemical cross-linking, which causes a gradual and nonreversible fracturing of the cross-linked network, a physically cross-linked binder based on PAA-PBI (poly(benzimidazole)) efficiently holds the Si particles even after the large volume changes due to its ability to reversibly reconstruct ionic bonds. The PBI-containing binder, PAA-PBI-2, exhibited large capacity (1376.7 mAh g(-1)), high Coulombic efficiency (99.1%) and excellent cyclability (751.0 mAh g(-1) after 100 cycles). This simple yet efficient method is promising to solve the failures relating with pulverization and isolation from the severe volume changes of the Si electrode, and advance the realization of high-capacity LIBs.

  16. Poly-N-Isopropylacrylamide/acrylic Acid Copolymers for the Generation of Nanostructures at Mica Surfaces and as Hydrophobic Host Systems for the Porin MspA from Mycobacterium smegmatis

    PubMed Central

    Gamage, Pubudu; Basel, Matthew T.; Lovell, Kimberly; Pokhrel, Megh Raj; Battle, Deletria; Ito, Takashi; Pavlenok, Mikhail; Niederweis, Michael

    2009-01-01

    The work presented here aims at utilizing poly-N-isopropyl-acrylamide/acrylic acid copolymers to create nanostructured layers on mica surfaces by a simple spin-casting procedure. The average composition of the copolymers determined by elemental analysis correlates excellently with the feed composition indicating that the radical polymerization process is statistical. The resulting surfaces were characterized by Atomic Force Microscopy (magnetic AC-mode) at the copolymer/air interface. Postpolymerization modification of the acrylic acid functions with perfluoro-octyl-iodide decreased the tendency towards spontaneous formation of nanopores. Crosslinking of individual polymer chains permitted the generation of ultraflat layers, which hosted the mycobacterial channel protein MspA, without compromising its channel function. The comparison of copolymers of very similar chemical composition that have been prepared by living radical polymerization and classic radical polymerization indicated that differences in polydispersity played only a minor role when poly-N-isopropyl-acrylamide/acrylic acid copolymers were spincast, but a major role when copolymers featuring the strongly hydrophobic perfluoro-octyl-labels were used. The mean pore diameters were 23.8±4.4 nm for P[(NIPAM)95.5-co-(AA)4.5] (PDI (polydispersity index)=1.55) and 21.8±4.2 nm for P[(NIPAM)95.3-co-(AA)4.7] (PDI=1.25). The depth of the nanopores was approx. 4 nm. When depositing P[(NIPAM)95-co-(AA)2.8-AAC8F17 2.2] (PDI=1.29) on Mica, the resulting mean pore diameter was 35.8±7.1 nm, with a depth of only 2 nm. PMID:20161351

  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. Advantages and limitations of the use of an extended polyelectrolyte model to describe the proton-binding process in macromolecular systems. Application to a poly(acrylic acid) and a humic acid.

    PubMed

    García-Mina, Jose M

    2007-05-03

    A number of studies have shown the suitability of the polyelectrolyte model to describe the proton-binding behavior of macromolecules. This model, however, has two limitations associated with its theoretical approach: (1) it does not consider the possible heterogeneity of binding sites, and (2) for certain calculations, it involves the need to assume a specific molecular geometry. In this article we describe the theoretical basis of an extension of the polyelectrolyte model that removes the two limitations described above. Likewise, we discuss the advantages and limitations of the extended polyelectrolyte model (EPM) through its application to describe the proton-binding process in a well-characterized macromolecular system (a poly(acrylic acid)) and a complex molecular system (a humic acid). The results obtained showed the suitability of EPM to describe proton-binding processes in complex molecular systems without the need to assume previously a specific molecular geometry and explicitly considering the possible heterogeneity of the binding sites. The results obtained indicated that the field effects associated with the conformational structure corresponding to each ionic strength, even in the discharged state, affect the values of the intrinsic constants defining the proton-binding process using EPM. Likewise, EPM analysis reveals the significant influence of both the surface charge density and the molecular size on the value of the electrostatic effects affecting the values of the intrinsic constants in the proton-binding process.

  19. 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.

  20. Lower critical solution temperature behavior of alpha-substituted poly(acrylic acids)s, cyclopolymerization of N-vinylformamido-methylacrylates, and use of the World-Wide Web in polymer science education

    NASA Astrophysics Data System (ADS)

    Michalovic, Mark Stephen

    A series of alpha-substituted poly(acrylic acid)s was synthesized and characterized. Their aqueous solution properties were investigated with respect to lower critical solution temperature (LCST) behavior. Poly(alpha-methoxymethylacrylic acid) was found to have a lower critical solution temperature (LCST) of 46°C, poly(alpha-methoxyethoxymethylacrylic acid) showed an LCST of 26.5°C and poly(alpha-methoxyethoxyethoxymethylacrylic acid) showed an LCST of 66°C. The cloud points of the solutions of these polymers were found to be sensitive to pH, and to concentrations of additives such as urea, salts, and surfactants. Because of low molecular weight due to chain transfer, high molecular weight analogs of the ether-linked polymers were synthesized in which ester linkages joined the oligo-oxyethylene segment to the acrylate moiety. Poly(alpha-methoxyethoxyacetoxymethylacrylic acid) was the only one of this series to give an LCST with a value of 52.5°C. Copolymers of t-butyl alpha-methoxymethylacrylate (tBMMA) with alpha-(1H,1H- perfluorooctyloxymethyl)acrylic acid (PFOMA) were synthesized, deprotected and their lower critical solution temperatures (LCSTs) evaluated. At PFOMA feed ratios of 0.25 mol % or less, no observable change in the LCST was observed, while at PFOMA feed ratios of above 0.25 mol % to 1.125 mol %, a large linear decrease in the LCST was observed with increasing fluorocarbon content. t-Butyl alpha-(N-vinylformamidomethyl)acrylate (tBVFA) and ethyl alpha-(N-vinylformamidomethyl)acrylate (EVFA) were synthesized from t-butyl alpha-bromomethylacrylate and ethyl alpha-chloromethylacrylate, respectively. tBVFA was found to cyclopolymerize at 120°C in DMF, DMSO, and 1,2-dichlorobenzene at solvent:monomer ratios of 10:1 vol:wt. Molecular weights for poly(tBVFA) ranged from 10,000 to 13,000 as estimated by size-exclusion chromatography. At lower solvent monomer ratio (1:1), and at lower temperature (71°C), crosslinking occurred. EVFA was found to

  1. 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.

  2. 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.

  3. 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.

  4. Wastewater disinfection by peracetic acid: assessment of models for tracking residual measurements and inactivation.

    PubMed

    Santoro, Domenico; Gehr, Ronald; Bartrand, Timothy A; Liberti, Lorenzo; Notarnicola, Michele; Dell'Erba, Adele; Falsanisi, Dario; Haas, Charles N

    2007-07-01

    With its potential for low (if any) disinfection byproduct formation and easy retrofit for chlorine contactors, peracetic acid (PAA) or use of PAA in combination with other disinfectant technologies may be an attractive alternative to chlorine-based disinfection. Examples of systems that might benefit from use of PAA are water reuse schemes or plants discharging to sensitive receiving water bodies. Though PAA is in use in numerous wastewater treatment plants in Europe, its chemical kinetics, microbial inactivation rates, and mode of action against microorganisms are not thoroughly understood. This paper presents results from experimental studies of PAA demand, PAA decay, and microbial inactivation, with a complementary modeling analysis. Model results are used to evaluate techniques for measurement of PAA concentration and to develop hypotheses regarding the mode of action of PAA in bacterial inactivation. Kinetic and microbial inactivation rate data were collected for typical wastewaters and may be useful for engineers in evaluating whether to convert from chlorine to PAA disinfection.

  5. 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...

  6. 21 CFR 177.1010 - Acrylic and modified acrylic plastics, semirigid and rigid.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true 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...

  7. 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...

  8. 21 CFR 177.1010 - Acrylic and modified acrylic plastics, semirigid and rigid.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acrylic and modified acrylic plastics, semirigid... Components of Single and Repeated Use Food Contact Surfaces § 177.1010 Acrylic and modified acrylic plastics, semirigid and rigid. Semirigid and rigid acrylic and modified acrylic plastics may be safely used...

  9. 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...

  10. Improvement of Uveal and Capsular Biocompatibility of Hydrophobic Acrylic Intraocular Lens by Surface Grafting with 2-Methacryloyloxyethyl Phosphorylcholine-Methacrylic Acid Copolymer

    PubMed Central

    Tan, Xuhua; Zhan, Jiezhao; Zhu, Yi; Cao, Ji; Wang, Lin; Liu, Sa; Wang, Yingjun; Liu, Zhenzhen; Qin, Yingyan; Wu, Mingxing; Liu, Yizhi; Ren, Li

    2017-01-01

    Biocompatibility of intraocular lens (IOL) is critical to vision reconstruction after cataract surgery. Foldable hydrophobic acrylic IOL is vulnerable to the adhesion of extracellular matrix proteins and cells, leading to increased incidence of postoperative inflammation and capsule opacification. To increase IOL biocompatibility, we synthesized a hydrophilic copolymer P(MPC-MAA) and grafted the copolymer onto the surface of IOL through air plasma treatment. X-ray photoelectron spectroscopy, atomic force microscopy and static water contact angle were used to characterize chemical changes, topography and hydrophilicity of the IOL surface, respectively. Quartz crystal microbalance with dissipation (QCM-D) showed that P(MPC-MAA) modified IOLs were resistant to protein adsorption. Moreover, P(MPC-MAA) modification inhibited adhesion and proliferation of lens epithelial cells (LECs) in vitro. To analyze uveal and capsular biocompatibility in vivo, we implanted the P(MPC-MAA) modified IOLs into rabbits after phacoemulsification. P(MPC-MAA) modification significantly reduced postoperative inflammation and anterior capsule opacification (ACO), and did not affect posterior capsule opacification (PCO). Collectively, our study suggests that surface modification by P(MPC-MAA) can significantly improve uveal and capsular biocompatibility of hydrophobic acrylic IOL, which could potentially benefit patients with blood-aqueous barrier damage. PMID:28084469

  11. 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...

  12. 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.

  13. Combined experimental and theoretical studies on the molecular structures, spectroscopy, and inhibitor activity of 3-(2-thienyl)acrylic acid through AIM, NBO,FT-IR, FT-Raman, UV and HOMO-LUMO analyses, and molecular docking

    NASA Astrophysics Data System (ADS)

    Issaoui, N.; Ghalla, H.; Bardak, F.; Karabacak, M.; Aouled Dlala, N.; Flakus, H. T.; Oujia, B.

    2017-02-01

    In this work, the molecular structures and vibrational spectral analyses of 3-(2-Theinyl)acrylic acid (3-2TAA) monomer and dimer structures have been reported by using density functional theory calculations at B3LYP/6-311++G(d,p) level of theory. The complete assignments of the fundamental vibrational modes were obtained using potential energy distribution. Intermolecular interactions were analyzed by orbital NBO and topological AIM approaches. The electronic properties have been carried out using TD-DFT approach. Great agreements between experimental and theoretical values were achieved throughout the analysis of structural parameters and spectroscopic features. Inhibitor characteristics on human monoamine oxidase B (MAOB) enzyme of two determined stable conformers of 3-2TAA (β and γ) along with four selective inhibitors, namely safinamide, a coumarin analogue, farnesol, and phenyethylhydrazine were investigated via molecular docking. Moreover, molecular electrostatic potential (MEP) and temperature dependency of thermodynamic functions have been reported.

  14. 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...

  15. In vitro and in vivo drug release and antibacterial properties of the novel vancomycin-loaded bone-like hydroxyapatite/poly amino acid scaffold

    PubMed Central

    Cao, Zhidong; Jiang, Dianming; Yan, Ling; Wu, Jun

    2017-01-01

    Antibiotic-loaded carriers were developed to fill cavities and locally deliver antibiotics following implantation. However, the most commonly used antibiotic carrier, polymethyl methacrylate (PMMA), has many disadvantages including that it does not promote bone regeneration or conduction. Vancomycin-loaded bone-like hydroxyapatite/poly amino acid (V-BHA/PAA) was successfully fabricated by a homogeneous method, certified as biosafe and known to promote osteogenesis. To evaluate its drug-release features, the quantity of the vancomycin in the elution was obtained every 2 days after in vitro simulated body fluid immersion. The drug concentration in the elution was determined to obtain the drug-release curve. The in vitro drug release was a three-phase process with two release peaks. Its antibacterial activity was evaluated in vitro using an antibacterial zone assay, antibacterial inhibition, and scanning electron microscopy (SEM) observation. Scaffolds of V-BHA/PAA were implanted into a rabbit model of chronic osteomyelitis. The antibacterial activity of the material was evaluated in vivo by gross observations, X-ray, and histological and ultrastructural observations. During the first 48 h, the vancomycin release was more rapid, followed by a period of sustained slow release. Use of V-BHA/PAA could achieve relatively long-term vancomycin delivery of 38 days in vitro and 42 days in vivo. V-BHA/PAA showed a significant and consistent bactericidal effect toward both Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in vitro and in vivo. Moreover, the bactericidal effect was stronger than that of vancomycin-loaded polymethyl meth acrylate (V-PMMA). The duration of the antibacterial effect of V-BHA/PAA toward both S. aureus and MRSA exceeded 28 days in vitro, while that of V-PMMA lasted only 14 days. The curative rate for V-BHA/PAA in the chronic osteomyelitis model was 75% for regular S. aureus and 66.67% for MRSA infection, which significantly exceeded

  16. In vitro and in vivo drug release and antibacterial properties of the novel vancomycin-loaded bone-like hydroxyapatite/poly amino acid scaffold.

    PubMed

    Cao, Zhidong; Jiang, Dianming; Yan, Ling; Wu, Jun

    2017-01-01

    Antibiotic-loaded carriers were developed to fill cavities and locally deliver antibiotics following implantation. However, the most commonly used antibiotic carrier, polymethyl methacrylate (PMMA), has many disadvantages including that it does not promote bone regeneration or conduction. Vancomycin-loaded bone-like hydroxyapatite/poly amino acid (V-BHA/PAA) was successfully fabricated by a homogeneous method, certified as biosafe and known to promote osteogenesis. To evaluate its drug-release features, the quantity of the vancomycin in the elution was obtained every 2 days after in vitro simulated body fluid immersion. The drug concentration in the elution was determined to obtain the drug-release curve. The in vitro drug release was a three-phase process with two release peaks. Its antibacterial activity was evaluated in vitro using an antibacterial zone assay, antibacterial inhibition, and scanning electron microscopy (SEM) observation. Scaffolds of V-BHA/PAA were implanted into a rabbit model of chronic osteomyelitis. The antibacterial activity of the material was evaluated in vivo by gross observations, X-ray, and histological and ultrastructural observations. During the first 48 h, the vancomycin release was more rapid, followed by a period of sustained slow release. Use of V-BHA/PAA could achieve relatively long-term vancomycin delivery of 38 days in vitro and 42 days in vivo. V-BHA/PAA showed a significant and consistent bactericidal effect toward both Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in vitro and in vivo. Moreover, the bactericidal effect was stronger than that of vancomycin-loaded polymethyl meth acrylate (V-PMMA). The duration of the antibacterial effect of V-BHA/PAA toward both S. aureus and MRSA exceeded 28 days in vitro, while that of V-PMMA lasted only 14 days. The curative rate for V-BHA/PAA in the chronic osteomyelitis model was 75% for regular S. aureus and 66.67% for MRSA infection, which significantly exceeded

  17. 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.

  18. 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

  19. 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.

  20. Properties of Ultra-Violet Cured Poly(diemthylsiloxane)-Urea Acrylates.

    DTIC Science & Technology

    1984-11-01

    polycaprolactone) and polyol molecular weight on physical properties were evaluated. TDI/ hydroxyethyl methacrylate ( HEMA ) based samples were also...diluents. The reactive diluents or crosslinkers I. chosen were: ethyl methacrylate (EMA), hydroxyethyl methacrylate ( HEMA ), butyl acrylate (BA...butylacrylate (BA), acrylic acid (AA), ethyl methacrylate (EMA), B- hydroxyethyl ’metthacrylate ( HEMA ), m~ethyl trethacrylate (MMA), and 4-vinylpyridine (4

  1. Modeling the free radical polymerization of acrylates

    NASA Astrophysics Data System (ADS)

    Günaydin, Hakan; Salman, Seyhan; Tüzün, Nurcan Şenyurt; Avci, Duygu; Aviyente, Viktorya

    Acrylates have gained importance because of their ease of conversion to high-molecular-weight polymers and their broad industrial use. Methyl methacrylate (MMA) is a well-known monomer for free radical polymerization, but its α-methyl substituent restricts the chemical modification of the monomer and therefore the properties of the resulting polymer. The presence of a heteroatom in the methyl group is known to increase the polymerizability of MMA. Methyl α-hydroxymethylacrylate (MHMA), methyl α-methoxymethylacrylate (MC1MA), methyl α-acetoxymethylacrylate (MAcMA) show even better conversions to high-molecular-weight polymers than MMA. In contrast, the polymerization rate is known to decrease as the methyl group is replaced by ethyl in ethyl α-hydroxymethylacrylate (EHMA) and t-butyl in t-butyl α-hydroxymethylacrylate (TBHMA). In this study, quantum mechanical tools (B3LYP/6-31G*) have been used in order to understand the mechanistic behavior of the free radical polymerization reactions of acrylates. The polymerization rates of MMA, MHMA, MC1MA, MAcMA, EHMA, TBHMA, MC1AN (α-methoxymethyl acrylonitrile), and MC1AA (α-methoxymethyl acrylic acid) have been evaluated and rationalized. Simple monomers such as allyl alcohol (AA) and allyl chloride (AC) have also been modeled for comparative purposes.

  2. Toxicity of peracetic acid (PAA) to tomonts of Ichthyophthirius multifiliis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The free-living infective theront of Ichthyophthirius multifiliis historically has been thought to be the only stage susceptible to treatment. A technique is introduced to determine the toxicity of compounds to the detached trophont, the settled tomont and the developing tomites within the tomont t...

  3. 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.

  4. 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.

  5. 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

    2015-08-04

    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.

  6. 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.

  7. Taxis of Pseudomonas putida F1 toward phenylacetic acid is mediated by the energy taxis receptor Aer2.

    PubMed

    Luu, Rita A; Schneider, Benjamin J; Ho, Christie C; Nesteryuk, Vasyl; Ngwesse, Stacy E; Liu, Xianxian; Parales, Juanito V; Ditty, Jayna L; Parales, Rebecca E

    2013-04-01

    The phenylacetic acid (PAA) degradation pathway is a widely distributed funneling pathway for the catabolism of aromatic compounds, including the environmental pollutants styrene and ethylbenzene. However, bacterial chemotaxis to PAA has not been studied. The chemotactic strain Pseudomonas putida F1 has the ability to utilize PAA as a sole carbon and energy source. We identified a putative PAA degradation gene cluster (paa) in P. putida F1 and demonstrated that PAA serves as a chemoattractant. The chemotactic response was induced during growth with PAA and was dependent on PAA metabolism. A functional cheA gene was required for the response, indicating that PAA is sensed through the conserved chemotaxis signal transduction system. A P. putida F1 mutant lacking the energy taxis receptor Aer2 was deficient in PAA taxis, indicating that Aer2 is responsible for mediating the response to PAA. The requirement for metabolism and the role of Aer2 in the response indicate that P. putida F1 uses energy taxis to detect PAA. We also revealed that PAA is an attractant for Escherichia coli; however, a mutant lacking a functional Aer energy receptor had a wild-type response to PAA in swim plate assays, suggesting that PAA is detected through a different mechanism in E. coli. The role of Aer2 as an energy taxis receptor provides the potential to sense a broad range of aromatic growth substrates as chemoattractants. Since chemotaxis has been shown to enhance the biodegradation of toxic pollutants, the ability to sense PAA gradients may have implications for the bioremediation of aromatic hydrocarbons that are degraded via the PAA pathway.

  8. Taxis of Pseudomonas putida F1 toward Phenylacetic Acid Is Mediated by the Energy Taxis Receptor Aer2

    PubMed Central

    Luu, Rita A.; Schneider, Benjamin J.; Ho, Christie C.; Nesteryuk, Vasyl; Ngwesse, Stacy E.; Liu, Xianxian; Parales, Juanito V.; Ditty, Jayna L.

    2013-01-01

    The phenylacetic acid (PAA) degradation pathway is a widely distributed funneling pathway for the catabolism of aromatic compounds, including the environmental pollutants styrene and ethylbenzene. However, bacterial chemotaxis to PAA has not been studied. The chemotactic strain Pseudomonas putida F1 has the ability to utilize PAA as a sole carbon and energy source. We identified a putative PAA degradation gene cluster (paa) in P. putida F1 and demonstrated that PAA serves as a chemoattractant. The chemotactic response was induced during growth with PAA and was dependent on PAA metabolism. A functional cheA gene was required for the response, indicating that PAA is sensed through the conserved chemotaxis signal transduction system. A P. putida F1 mutant lacking the energy taxis receptor Aer2 was deficient in PAA taxis, indicating that Aer2 is responsible for mediating the response to PAA. The requirement for metabolism and the role of Aer2 in the response indicate that P. putida F1 uses energy taxis to detect PAA. We also revealed that PAA is an attractant for Escherichia coli; however, a mutant lacking a functional Aer energy receptor had a wild-type response to PAA in swim plate assays, suggesting that PAA is detected through a different mechanism in E. coli. The role of Aer2 as an energy taxis receptor provides the potential to sense a broad range of aromatic growth substrates as chemoattractants. Since chemotaxis has been shown to enhance the biodegradation of toxic pollutants, the ability to sense PAA gradients may have implications for the bioremediation of aromatic hydrocarbons that are degraded via the PAA pathway. PMID:23377939

  9. Properties of extruded starch-poly(methyl acrylate) graft copolymers prepared from spherulites formed from amylose-oleic acid inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mixtures of high amylose corn starch and oleic acid were processed by steam jet-cooking, and the dispersions were rapidly cooled to yield amylose-oleic acid inclusion complexes as sub-micron spherulites and spherulite aggregates. Dispersions of these spherulite particles were then graft polymerized ...

  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. Acrylates and Methacrylates,

    DTIC Science & Technology

    1987-09-15

    of ethylene and hydrocyanic acid through ethylene cyanohydrin. In the presence of basic catalysts ethylene oxide easily adds hydrocyanic acid with the...of synthesis of methacrylates. At present methacrylates are obtained in the industry by continuous method from acetone and hydrocyanic acid through...acetone cyanohydrin. The addition/connection to it of hydrocyanic acid with the formation of acetone cyanohydrin is one of the most important reactions

  12. 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.

  13. Improvement in the water retention characteristics of sandy loam soil using a newly synthesized poly(acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite material.

    PubMed

    Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

    2012-08-03

    The use of some novel and efficient crop nutrient-based superabsorbent hydrogel nanocomposites (SHNCs), is currently becoming increasingly important to improve the crop yield and productivity, due to their water retention properties. In the present study a poly(Acrylamide-co-acrylic acid)/AlZnFe2O4 superabsorbent hydrogel nanocomposite was synthesized and its physical properties characterized using Energy Dispersive X-ray (EDX), FE-SEM and FTIR spectroscopic techniques. The effects of different levels of SHNC were studied to evaluate the moisture retention properties of sandy loam soil (sand 59%, silt 21%, clay 19%, pH 7.4, EC 1.92 dS/m). The soil amendment with 0.1, 0.2, 0.3 and 0.4 w/w% of SHNC enhanced the moisture retention significantly at field capacity compared to the untreated soil. Besides, in a separate experiment, seed germination and seedling growth of wheat was found to be notably improved with the application of SHNC. A delay in wilting of seedlings by 5-8 days was observed for SHNC-amended soil, thereby improving wheat plant growth and establishment.

  14. Cyto- and genotoxicological assessment and functional characterization of N-vinyl-2-pyrrolidone-acrylic acid-based copolymeric hydrogels with potential for future use in wound healing applications.

    PubMed

    Kirf, Dominik; Higginbotham, Clement L; Rowan, Neil J; Devery, Sinéad M

    2010-06-01

    This study investigated the toxicity of N-vinyl-2-pyrrolidone-acrylic acid copolymer hydrogels crosslinked with ethylene glycol dimethacrylate or poly(ethylene glycol) dimethacrylate. There is a pressing need to establish the toxicity status of these new copolymers because they may find applications in future wound healing processes. Investigations revealed that the capacity of these hydrogels for swelling permitted the retention of high amounts of water yet still maintaining structural integrity. Reverse phase HPLC analysis suggested that unreacted monomeric base material was efficiently removed post-polymerization by applying an additional purification process. Subsequently, in vitro toxicity testing was performed utilizing direct and indirect contact exposure of the polymers to human keratinocytes (HaCaT) and human hepatoma (HepG2) cells. No indication of significant cell death was observed using the established MTT, neutral red (NR) and fluorescence-based toxicity endpoint indicators. In addition, the alkaline Comet assay showed no genotoxic effects following cell exposure to hydrogel extracts. Investigations at the nucleotide level using the Ames mutagenicity assay demonstrated no evidence of mutagenic activity associated with the polymers. Findings from this study demonstrated that these hydrogels are non-cytotoxic and further work can be carried out to investigate their potential as a wound-healing device that will impact positively on patient health and well-being.

  15. Preparation of thermoresponsive Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) magnetic composite microspheres with controlled shell thickness and its releasing property for phenolphthalein.

    PubMed

    Zhang, Baoliang; Zhang, Hepeng; Fan, Xinlong; Li, Xiangjie; Yin, Dezhong; Zhang, Qiuyu

    2013-05-15

    In this work, Fe3O4/P(acrylic acid-methyl methacrylate-N-isopropylacrylamide) (Fe3O4/P(AA-MMA-NIPAm)) thermoresponsive magnetic composite microspheres have been prepared by controlled radical polymerization in the presence of 1,1-diphenylethene (DPE). The shell thickness of thermosensitive polymer (PNIPAm), which was on the surface of the microspheres, can be controlled by using DPE method. The morphology and thermosensitive properties of the composite microspheres, polymerization mechanism of the shell were characterized by TEM, FTIR, VSM, Laser Particle Sizer, TGA, NMR, and GPC. The microspheres with narrow particle size distribution show high saturation magnetization and superparamagnetism. The thermosensitive properties of the composite microspheres can be adjusted indirectly via controlling the addition amount of monomer (NIPAm) in the second step during controlled radical polymerization. Phenolphthalein was chosen as a model drug to investigate drug release behavior of the thermoresponsive magnetic composite microspheres with different shell thickness. Controlled drug release testing reveals that the release behavior depends on the thickness of polymer on the surface of the microspheres.

  16. Enhancement of light harvesting efficiency of silicon solar cell utilizing arrays of poly(methyl methacrylate-co-acrylic acid) nano-spheres and nano-spheres with embedded silver nano-particles

    NASA Astrophysics Data System (ADS)

    Lee, Chee-Leong; Goh, Wee-Sheng; Chee, Swee-Yong; Yik, Lai-Kuan

    2017-02-01

    An array of uniformly distributed monolayer of poly(methyl methacrylate-co-acrylic acid) nano-spheres were deposited onto an amorphous silicon photovoltaic cell utilizing dip coating technique. The electrical characteristics of the coated photovoltaic cell reveal that the nano-spheres with an average diameter size of 101 nm exhibits excellent light harvesting characteristics if compared to the nano-spheres of other sizes. The power conversion efficiency from such integration of the nano-structures (i.e. 3.14% per PV cell) indicates that at least 1.6 times of improvement (or relative enhancement of 57%) can be achieved comparatively to the uncoated photovoltaic cell (i.e. 2% per PV cell). Further increment of the power conversion efficiency of the solar cell has been attained with the incorporation of the silver nano-particles into the nano-spheres of similar average size. With the inclusion of the silver nano-particles into such nano-spheres, the power conversion efficiency of the solar cell has attained 5.57% per PV cell, which is about 2.8 times (or relative enhancement of 179%) if compared to the uncoated samples. Hence, this novel and controllable technique of fabricating omnidirectional light-harvesting nano-spheres with embedded silver nano-particles will indubitably be beneficial to various types of optoelectronic devices.

  17. Solvent effects on the formation of nanoparticles and multilayered coatings based on hydrogen-bonded interpolymer complexes of poly(acrylic acid) with homo- and copolymers of N-vinyl pyrrolidone.

    PubMed

    Zhunuspayev, Daulet E; Mun, Grigoriy A; Hole, Patrick; Khutoryanskiy, Vitaliy V

    2008-12-02

    The formation of hydrogen-bonded interpolymer complexes between poly(acrylic acid) and poly(N-vinyl pyrrolidone) as well as amphiphilic copolymers of N-vinyl pyrrolidone with vinyl propyl ether has been studied in aqueous and organic solutions. It was demonstrated that introduction of vinyl propyl ether units into the macromolecules of the nonionic polymer enhances their ability to form complexes in aqueous solutions due to more significant contribution of hydrophobic effects. The complexation was found to be a multistage process that involves the formation of primary polycomplex particles, which further aggregate to form spherical nanoparticles. Depending on the environmental factors (pH, solvent nature), these nanoparticles may either form stable colloidal solutions or undergo further aggregation, resulting in precipitation of interpolymer complexes. In organic solvents, the intensity of complex formation increases in the following order: methanol < ethanol < isopropanol < dioxane. The multilayered coatings were developed using layer-by-layer deposition of interpolymer complexes on glass surfaces. It was demonstrated that the solvent nature affects the efficiency of coating deposition.

  18. 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).

  19. Intelligent core-shell nanoparticles and hollow spheres based on gelatin and PAA via template polymerization.

    PubMed

    Wang, Yansong; Zhang, Youwei; Du, Weiping; Wu, Chengxun; Zhao, Jiongxin

    2009-06-15

    PAA/gelatin nanoparticles, with interpolymer complexes of gelatin and polyacrylic acid (PAA) as the cores and gelatin as the shells, were prepared via facile polymerization of AA on gelatin template. The morphology change of the nanoparticles during the reaction was traced by a combined use of dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques, which revealed a discrepancy among the structure of the nanoparticles formed at different stages of the reaction: as the reaction proceeds, nanoparticles with larger compact cores and thinner shells are produced. The resultant nanoparticles are multi-responsive. Especially, they exhibit a significant temperature-dependent size change: upon raising the temperature from 25 degrees C, the nanoparticle size decreases monotonically until reaching equilibrium at about 40 degrees C. This temperature-dependence of the nanoparticle size was found to be reversible provided the nanoparticle solution was cooled at a low temperature (4 degrees C). The thermo-sensitivity of the nanoparticles is attributed to the thermo-induced sol-gel transition of the gelatin shells. In addition, the nanoparticles were further converted to hollow spheres via successive locking the shell structure by the reaction of gelatin with cross-linker glutaraldehyde, and cavitation of the cross-linked nanoparticles by switching the medium from acidic to neutral. The cavitation process was monitored by DLS, which indicated a mass decrease and size shrinkage. AFM and transmission electron microscopy (TEM) were used to trace the morphology change of the nanoparticles during the cavitation. The hollow structure was confirmed by TEM observation.

  20. 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

    2015-02-03

    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.

  1. Elucidating the role of the phenylacetic acid metabolic complex in the pathogenic activity of Rhizoctonia solani anastomosis group 3.

    PubMed

    Bartz, Faith E; Glassbrook, Norman J; Danehower, David A; Cubeta, Marc A

    2012-01-01

    The soil fungus Rhizoctonia solani produces phytotoxic phenylacetic acid (PAA) and hydroxy (OH-) and methoxy (MeO-) derivatives of PAA. However, limited information is available on the specific role that these compounds play in the development of Rhizoctonia disease symptoms and concentration(s) required to induce a host response. Reports that PAA inhibits the growth of R. solani conflict with the established ability of the fungus to produce and metabolize PAA. Experiments were conducted to clarify the role of the PAA metabolic complex in Rhizoctonia disease. In this study the concentration of PAA and derivatives required to induce tomato root necrosis and stem canker, in the absence of the fungus, and the concentration that inhibits mycelial growth of R. solani were determined. The effect of exogenous PAA and derivatives of PAA on tomato seedling growth also was investigated. Growth of tomato seedlings in medium containing 0.1-7.5 mM PAA and derivatives induced necrosis of up to 85% of root system. Canker development resulted from injection of tomato seedling stems with 7.5 mM PAA, 3-OH-PAA, or 3-MeO-PAA. PAA in the growth medium reduced R. solani biomass, with 50% reduction observed at 7.5 mM. PAA, and derivatives were quantified from the culture medium of 14 isolates of R. solani belonging to three distinct anastomosis groups by GC-MS. The quantities ranged from below the limit of detection to 678 nM, below the concentrations experimentally determined to be phytotoxic. Correlation analyses revealed that isolates of R. solani that produced high PAA and derivatives in vitro also caused high mortality on tomato seedlings. The results of this investigation add to the body of evidence that the PAA metabolic complex is involved in Rhizoctonia disease development but do not indicate that production of these compounds is the primary or the only determinant of pathogenicity.

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 63 FR 41279 - Acrylic Sheet From Japan

    Federal Register 2010, 2011, 2012, 2013, 2014

    1998-08-03

    ... COMMISSION Acrylic Sheet From Japan AGENCY: United States International Trade Commission. ACTION: Institution of a five-year review concerning the antidumping duty order on acrylic sheet from Japan. SUMMARY: The... order on acrylic sheet from Japan would be likely to lead to continuation or recurrence of...

  7. Langmuir-Blodgett films of random copolymers of fluoroalkyl(meth)acrylate and methacrylic acid: Fabrication and X-ray diffraction study

    SciTech Connect

    Safronov, V.; Feigin, L.A.; Budovskaya, L.D.; Ivanova, V.N.

    1994-12-31

    Langmuir-Blodgett films of amphiphilic fluorinated copolymers were fabricated and studied by X-ray diffraction. Although these films show poor interlayer periodicity, they possess a uniform thickness even in the case of very thin films of one bilayer (22 {angstrom}). This feature was used to obtain complex LB structures (superlattices) with alteration of copolymer and fatty acid bilayers. X-ray diffraction data proved the regular periodical organization of these structures and allowed to calculate electron density distribution across the superlattices.

  8. Peracetic acid-ionic liquid pretreatment to enhance enzymatic saccharification of lignocellulosic biomass.

    PubMed

    Uju; Abe, Kojiro; Uemura, Nobuyuki; Oshima, Toyoji; Goto, Masahiro; Kamiya, Noriho

    2013-06-01

    To enhance enzymatic saccharification of pine biomass, the pretreatment reagents peracetic acid (PAA) and ionic liquid (IL) were validated in single reagent pretreatments or combination pretreatments with different sequences. In a 1h saccharification, 5-25% cellulose conversion was obtained from the single pretreatment of PAA or IL. In contrast, a marked enhancement in conversion rates was achieved by PAA-IL combination pretreatments (45-70%). The PAA followed by IL (PAA+IL) pretreatment sequence was the most effective for preparing an enzymatic digestible regenerated biomass with 250-fold higher glucose formation rates than untreated biomass and 2- to 12-fold higher than single pretreatments with PAA or IL alone. Structural analysis confirmed that this pretreatment resulted in biomass with highly porous structural fibers associated with the reduction of lignin content and acetyl groups. Using the PAA+IL sequence, biomass loading in the pretreatment step can be increased from 5% to 15% without significant decrease in cellulose conversion.

  9. 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)

  10. Synergistic effect of additives including multifunctional acrylates in wood plastic composites

    NASA Astrophysics Data System (ADS)

    Khan, Mubarak A.; Idriss Ali, K. M.; Garnett, John L.

    1993-07-01

    Wood Plastic Composite (WPC) was prepared with simul (soft wood, density = 0.4g/cc) and butylmethacrylate (BMA) monomer using 10% methanol as the swelling agent. Effect of additives including (i) multifunctional acrylates such as tripropylene glycol diacrylate (TPGDA), trimethylol propane triacrylate (TMPTA) (ii) oligomer acrylates like the urethane (UA), epoxy (EA) and polyester (PEA) acrylates and (iii) N-vinyl pyrrolidone (NVP) was investigated using 1 to 3 Mrad dose at 0.8 Mrad/h. Synergistic increases in polymer loading yields was achieved in presence of the additives, particularly with the trifunctional acrylate (TMPTA). In addition, acid as well as urea were also used as co-additives and synergistic enhancement in yields of polymer loading were obtained. The synergistic polymer loading by acid addition causes substantial decrease in tensile strength of the composite; but other additives and co-additives increase both the polymer loading and the tensile strength in these systems.

  11. 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

    2014-09-02

    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.

  12. 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

  13. In vitro and in vivo efficacy of doxorubicin loaded biodegradable semi-interpenetrating hydrogel implants of poly (acrylic acid)/gelatin for post surgical tumor treatment.

    PubMed

    Jaiswal, Maneesh; Naz, Farhat; Dinda, Amit K; Koul, Veena

    2013-08-01

    The paper describes the preparation and evaluation of doxorubicin loaded semi-interpenetrating polymeric hydrogel network of polyacrylic acid (PAc) and gelatin (G). Post surgical antitumor efficacy and biodistribution of doxorubicin from the implanted degradable hydrogels was investigated on Ehrlich's ascites tumor model using albino mice. Polycaprolactone diacrylate (PCL-DAr) was employed as a crosslinking agent for PAc chains whereas G was kept free. The effect of crosslinking concentration on various physico-chemical properties such as thermal behavior, swelling, degradation behavior, drug release and polymer-polymer interactions was investigated by various physico-chemical tools. Semi-interpenetrating polymeric networks (IPNs) with 0.2 mol% crosslinking concentration showed degradation within 20 days in phosphate buffer (pH 6.5). To determine the in vivo anticancer efficacy, placebo and drug laden cylindrical implants (65 ± 5 µg/implant of 10 mg) were implanted in tumor cavity post tumor excision. After predetermined time intervals (day 7, 11, 14, 20 and 25), drug biodistribution was assessed in tumor, tumor periphery, residual hydrogel and all vital organs i.e. liver, spleen, kidney, heart, lung and blood (spectrofluorimetrically). The drug distribution study showed the concentration of drug in the tumor, tumor periphery and residual hydrogel decreased with increasing time; on the 7th day, drug concentration was highest while, on the 25th day, it was negligible; however, insignificant quantities of the drug was found in vital organs. Histological examination revealed no sign of tumor recurrence until the 25th day with 100% necrosis and slight inflammation in treated the group. In vivo results established that these biodegradable implants can be utilized as post surgical therapy for solid tumors.

  14. 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.

  15. 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...

  16. 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...

  17. 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...

  18. Testing Consent Order for Acrylic Acid

    EPA Pesticide Factsheets

    This document announces that EPA has signed an enforceable testing Consent Order with BASF Corporation, Dow Chemical U.S.A., Hoechst Celanese Chemical Group, Rohm and Haas Company, and Union Carbide Chemicals and Plastics, Inc.

  19. PAA: an R/bioconductor package for biomarker discovery with protein microarrays

    PubMed Central

    Turewicz, Michael; Ahrens, Maike; May, Caroline; Marcus, Katrin; Eisenacher, Martin

    2016-01-01

    Summary: The R/Bioconductor package Protein Array Analyzer (PAA) facilitates a flexible analysis of protein microarrays for biomarker discovery (esp., ProtoArrays). It provides a complete data analysis workflow including preprocessing and quality control, uni- and multivariate feature selection as well as several different plots and results tables to outline and evaluate the analysis results. As a main feature, PAA’s multivariate feature selection methods are based on recursive feature elimination (e.g. SVM-recursive feature elimination, SVM-RFE) with stability ensuring strategies such as ensemble feature selection. This enables PAA to detect stable and reliable biomarker candidate panels. Availability and implementation: PAA is freely available (BSD 3-clause license) from http://www.bioconductor.org/packages/PAA/. Contact: michael.turewicz@rub.de or martin.eisenacher@rub.de PMID:26803161

  20. 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

  1. Development of Electrically Conductive Transparent Coatings for Acrylic Plastic

    DTIC Science & Technology

    1952-12-01

    and methyl methacrylate monomer (I mole) in cyciohexanone (Z moles) vw’th benzoyl peroxide catalyst (0, Z% of total weight). The mix- ture was refluxed... methacrylic acid- methyl methaerylate copolymer re•I. The composite material, i. e., the acrylic and applied coating, retains essentially all the original...0.001" to 0.002" when rolled on and of less than 0.001" when sprayed on. The ability of the methacrylic acid- methyl methacrylate copolymer to cover the

  2. PAA1, a P-Type ATPase of Arabidopsis, Functions in Copper Transport in Chloroplasts

    PubMed Central

    Shikanai, Toshiharu; Müller-Moulé, Patricia; Munekage, Yuri; Niyogi, Krishna K.; Pilon, Marinus

    2003-01-01

    Copper (Cu) is an essential trace element with important roles as a cofactor in many plant functions, including photosynthesis. However, free Cu ions can cause toxicity, necessitating precise Cu delivery systems. Relatively little is known about Cu transport in plant cells, and no components of the Cu transport machinery in chloroplasts have been identified previously. Cu transport into chloroplasts provides the cofactor for the stromal enzyme copper/zinc superoxide dismutase (Cu/ZnSOD) and for the thylakoid lumen protein plastocyanin, which functions in photosynthetic electron transport from the cytochrome b6f complex to photosystem I. Here, we characterized six Arabidopsis mutants that are defective in the PAA1 gene, which encodes a member of the metal-transporting P-type ATPase family with a functional N-terminal chloroplast transit peptide. paa1 mutants exhibited a high-chlorophyll-fluorescence phenotype as a result of an impairment of photosynthetic electron transport that could be ascribed to decreased levels of holoplastocyanin. The paa1-1 mutant had a lower chloroplast Cu content, despite having wild-type levels in leaves. The electron transport defect of paa1 mutants was evident on medium containing <1 μM Cu, but it was suppressed by the addition of 10 μM Cu. Chloroplastic Cu/ZnSOD activity also was reduced in paa1 mutants, suggesting that PAA1 mediates Cu transfer across the plastid envelope. Thus, PAA1 is a critical component of a Cu transport system in chloroplasts responsible for cofactor delivery to plastocyanin and Cu/ZnSOD. PMID:12782727

  3. 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.

  4. 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...

  5. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Acrylate ester copolymer coating. 175.210 Section... Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as... prepared food, subject to the provisions of this section: (a) The acrylate ester copolymer is a...

  6. Monolithic F-16 Uniform Thickness Stretched Acrylic Canopy Transparency Program

    DTIC Science & Technology

    1984-01-01

    Thermoforming Finite Strain Analysis Finite Element Modeling Mooney Formulation Tensile Testing Acrylic Material Properties F-16 Transparency Thinning Uniform...OF ACRYLIC TENSILE SPECIMEN ...... 8 MARC ANALYSIS OF ACRYLIC HEMISPHERE ............ 12 IV ACRYLIC MATERIAL PROPERTIES AT THERMOFORMING TEMPERATURES...properties (necessary for finite element stress analysis work) were generated at temperatures in the range of thermoforming . A finite element code

  7. Poly(meth)acrylate-based coatings.

    PubMed

    Nollenberger, Kathrin; Albers, Jessica

    2013-12-05

    Poly(meth)acrylate coatings for pharmaceutical applications were introduced in 1955 with the launch of EUDRAGIT(®) L and EUDRAGIT(®) S, two types of anionic polymers. Since then, by introducing various monomers into their polymer chains and thus altering their properties, diverse forms with specific characteristics have become available. Today, poly(meth)acrylates function in different parts of the gastrointestinal tract and/or release the drug in a time-controlled manner. This article reviews the properties of various poly(meth)acrylates and discusses formulation issues as well as application possibilities.

  8. New radiopaque acrylic bone cement. II. Acrylic bone cement with bromine-containing monomer.

    PubMed

    Rusu, M C; Ichim, I C; Popa, M; Rusu, M

    2008-07-01

    Bromine-containing methacrylate, 2-(2-bromopropionyloxy) ethyl methacrylate (BPEM), had been used in the formulation of acrylic radiopaque cements. The effect of this monomer incorporated into the liquid phase of acrylic bone cement, on the curing parameters, thermal properties, water absorption, density, compression tests and radiopacity was studied. A decrease of maximum temperature and an increase of the setting time were observed with the addition of the bromine-containing monomer in the radiolucent cement composition. Adding BPEM in radiolucent acrylic bone cements composition results in the decrease of glass transition temperature and increase of its thermal stability. Acrylic bone cements modified with bromine-containing comonomer are characterized by polymerization shrinkage lower than the radiolucent cement. Addition of bromine-containing comonomer in radiolucent acrylic bone cement composition determines the increase of compressive strength. Acrylic bone cements modified with bromine-containing comonomer proved to be radiopaque.

  9. 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...

  10. 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 ...

  11. Peracetic acid is effective for controlling fungus on channel catfish eggs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Peracetic acid (PAA) is a relatively new compound suggested for use to treat pathogens in aquaculture. It 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 eggs. The study consisted...

  12. EVALUATION OF AN ACRYLATE TERPOLYMER, POLYURETHANE COMPOSITE.

    DTIC Science & Technology

    Composite films consisting of a flexible acrylate terpolymer substrate and an outer layer of poly (ester-urethane) elastomer were prepared and evaluated for use in cosmetic glove applications. (Author)

  13. 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

  14. Mechanism of Bacillus subtilis Spore Inactivation by and Resistance to Supercritical CO2 plus Peracetic Acid

    PubMed Central

    Setlow, Barbara; Korza, George; Blatt, Kelly M.S.; Fey, Julien P.; Setlow, Peter

    2015-01-01

    Aims Determine how supercritical CO2 (scCO2) plus peracetic acid (PAA) inactivates Bacillus subtilis spores, factors important in spore resistance to scCO2-PAA, and if spores inactivated by scCO2-PAA are truly dead. Methods and Results Spores of wild-type B. subtilis and isogenic mutants lacking spore protective proteins were treated with scCO2-PAA in liquid or dry at 35°C. Wild-type wet spores (aqueous suspension) were more susceptible than dry spores. Treated spores were examined for viability (and were truly dead), dipicolinic acid (DPA), mutations, permeability to nucleic acid stains, germination under different conditions, energy metabolism and outgrowth. ScCO2-PAA-inactivated spores retained DPA, and survivors had no notable DNA damage. However, DPA was released from inactivated spores at a normally innocuous temperature (85°C), and colony formation from treated spores was salt sensitive. The inactivated spores germinated but did not outgrow, and these germinated spores had altered plasma membrane permeability and defective energy metabolism. Wet or dry coat-defective spores had increased scCO2-PAA sensitivity, and dry spores but not wet spores lacking DNA protective proteins were more scCO2-PAA sensitive. Conclusions These findings suggest that scCO2-PAA inactivates spores by damaging spores’ inner membrane. The spore coat provided scCO2-PAA resistance for both wet and dry spores. DNA protective proteins provided scCO2-PAA resistance only for dry spores. Significance and Impact of Study These results provide information on mechanisms of spore inactivation of and resistance to scCO2-PAA, an agent with increasing use in sterilization applications. PMID:26535794

  15. Chemical Stress Cracking of Acrylic Fibers.

    DTIC Science & Technology

    1982-05-01

    nitrile groups (similar to the "prefatory reaction" in pyrolysis of acrylic fibers), followed immediately by N- chlorination and7 chain scission...cyclization of nitrile groups (similar to the "prefatory reaction" in pyrolysis of acrylic fibers), followed immediately by N- chlorination and chain scission...present experiments were conducted at the boil, slightly greater than 100 C. The decomposition products-- chlorine , chlorate, plus oxygen originating

  16. [Enhanced reductive decoloration of methylene blue by polyacrylic acid modified zero-valent iron nanoparticles].

    PubMed

    He, Jing; Wang, Xiang-Yu; Wang, Pei; Liu, Kun-Qian

    2015-03-01

    Nano zerovalent iron ( NZVI) technology has attracted tremendous amount of interests for degrading a number of environmental contaminants found both in surface water and underground water. However, these nanoscale particles are prone to aggregate, which may result in the decrease of its reactivity in liquid phase. Iron nanoparticles (Fe NPs) modified with polyacrylic acid (PAA) has enhanced the dispersion of NZVI and reduced its agglomeration. For the first time, PAA modified NPs (PAA-Fe NPs) were used for degradation of methylene blue in water phase. The PAA-Fe NPs prepared were characterized in terms of TEM, SEM, XRD and specific surface area. The results indicated that, the surface area of PAA-Fe NPs was increased, compared with unmodified pristine zero-valent iron NPs, and PAA-Fe NPs were smoother with smaller particle size. With addition of 0.1 g x L(-1) of PAA, the decolorization efficiency of methylene blue by PAA-Fe NPs was 98.84% in 60 min, which was 27.32% higher than that of pristine Fe NPs. Decolorization efficiencies were also affected by initial pH value, initial concentration of methylene blue, dosage of PAA-Fe NPs, and degradation temperature. Kinetic analyses based on the experimental data illustrated that the decolorization reaction of methylene blue fitted well to the pseudo first-order kinetics model.

  17. 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

    2015-04-08

    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.

  18. [Efficient killing of anthrax spores using aqueous and alcoholic peracetic acid solutions].

    PubMed

    Nattermann, H; Becker, S; Jacob, D; Klee, S R; Schwebke, I; Appel, B

    2005-08-01

    We analysed the sporicidal effect of different concentrations of aqueous and alcoholic peracetic acid (PAA) solutions on anthrax spores in suspension and germ carrier tests. In activation of anthrax spores in suspension assays was achieved in less than 2 min using 1% PAA solution and in less than 3 min using 0.5% PAA solution, respectively. In contrast, in germ carrier as says, a test under practical conditions, spores on 38% of the germ carriers survived treatment with 1% PAA solution for 15 min. The use of PAA in 80% ethyl alcohol outclassed the sporicidal effect of aqueous PAA solutions in both suspension and germ carrier assays. Anthrax spores on 14% of germ carriers tested survived 30 min of treatment with a 1% aqueous PAA solution. In contrast anthrax spores were reliably inactivated under the same test procedure using a 1% alcoholic PAA solution for 30 min. The proven enhancement of the sporicidal effect of alcoholic PAA solutions should be kept in mind when using disinfectants in practice. In further surveys we will optimise the test conditions.

  19. Synthesis and characterization of acrylic-based superabsorbents

    SciTech Connect

    Askari, F.; Nafisi, S.; Omidian, H.; Hashemi, S.A. )

    1993-12-10

    This paper is devoted to the synthesis and characterization of superabsorbent polymers based on acrylic acid. These hydrogels were prepared by carrying the inverse suspension polymerization in an aromatic hydrocarbon. The dispersion is stabilized by the mixture of micromolecular and macromolecular emulsifiers. To obtain high swelling and appropriate absorption kinetics, parameters such as initial monomer and cross-linker concentration, range of neutralization, monomer addition rate, temperature, initiating system, stabilizing system and nature of the organic phase were studied but not reviewed here. Thus, based on these topics a basic formula is obtained to display the effect of some structural parameters on behavior of superabsorbents utilized.

  20. Improved Cycling Performance of a Si Nanoparticle Anode Utilizing Citric Acid as a Surface-Modifying Agent.

    PubMed

    Nguyen, Cao Cuong; Seo, Daniel M; Chandrasiri, K W D K; Lucht, Brett L

    2016-12-20

    Citric acid and its analogues have been investigated as surface-modifying agents for Si nanoparticle anodes using electrochemical cycling, attenuated total reflectance infrared (ATR IR), and X-ray photoelectron spectroscopy (XPS). A Si nanoparticle anode prepared with citric acid (CA) has better capacity retention than one containing 1,2,3,4-butanetetracarboxylic acid (BA), but both electrodes outperform Si-PVDF. The Si-CA anode has an initial specific capacity of 3530 mA h/g and a first cycle efficiency of 82%. Surprisingly, the Si-CA electrode maintains a high specific capacity of ∼2200 mA h/g after 250 cycles, corresponding to 64% capacity retention, which is similar to the Si prepared with long-chain poly(acrylic acid) (PAA). On the contrary, the silicon electrode prepared with PVDF has a fast capacity fade and retains only 980 mA h/g after 50 cycles. The IR and XPS data show that the Si-CA electrode has an SEI composed primarily of lithium citrate during the first 50 cycles, resulting from the electrochemical reduction of citric acid. Only low concentrations of electrolyte reduction products are observed. The lithium citrate layer derived from CA stabilizes the silicon surface and suppresses electrolyte reduction, which likely contributes to the enhanced cycling performance of the Si nanoparticle anode.

  1. 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.

  2. Multi-functional hybrid coatings containing silica nanoparticles and anti-corrosive acrylate monomer for scratch and corrosion resistance.

    PubMed

    Seo, Ji Yeon; Han, Mijeong

    2011-01-14

    Multi-functional hybrid coatings having both anti-corrosion and scratch resistance were prepared from modified silica nanoparticles and functional acrylates. To improve the dispersion properties of silica nanoparticles in the organic/inorganic hybrid coatings, the surface of the nanoparticles was modified with γ-methacryloxypropyltrimethoxysilane. The coating solution could be prepared by mixing modified silica nanoparticles, tetrasiloxane acrylate, di-acrylate monomer containing an anti-corrosion functional group, acrylic acid, and an initiator in a solvent. The mixture was then dip-coated on iron substrates and finally polymerized by ultraviolet (UV) irradiation. Corrosion and scratch resistance of the coated iron was evaluated by electrochemical impedance spectroscopy (EIS) and a pencil hardness test, respectively. From the EIS results, the coatings with tetrasiloxane acrylate and di-acrylate did not show any decrease in impedance or phase angle, even after 50 days' exposure to 0.1 M NaCl electrolyte, whereas the conventional acrylate coatings started to fail after only 24 h. A hybrid coating containing the amine-quinone functional group exhibited excellent corrosion protection properties with 4-5H pencil hardness.

  3. Influencing Solvent Miscibility and Aqueous Stability of Aluminum Nanoparticles through Surface Functionalization with Acrylic Monomers (Postprint)

    DTIC Science & Technology

    2010-08-26

    Methacryloxypropyltrimethoxysilane (MPS), 2-carboxyethyl acrylate (CEA), phosphoric acid 2-hy- droxyethyl methacrylate ester (PAM), methyl methacrylate (MMA), cyclohexanone ...0.070 g, 0.43 mmol) was dissolved in dry cyclohexanone (25 mL) and added to the reaction vessel via the use of a cannula. The vessel was then immersed

  4. 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...

  5. 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...

  6. 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.

  7. 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

  8. [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.

  9. Synthesis and electromechanical characterization of a new acrylic dielectric elastomer with high actuation strain and dielectric strength

    NASA Astrophysics Data System (ADS)

    Hu, Wei; Niu, Xiaofan; Yang, Xinguo; Zhang, Naifang; Pei, Qibing

    2013-04-01

    Dielectric Elastomers (DEs) can be actuated under high electric field to produce large strains. Most high-performing DE materials such as the 3M™ VHB™ membranes are commercial products designed for industrial pressure-sensitive adhesives. The limited knowledge of the exact chemical structures of these commercial materials has made it difficult to understand the relationship between molecular structures and electromechanical properties. In this work, new acrylic elastomers based on n-butyl acrylate and acrylic acid were synthesized from monomer solutions by UV-initiated bulk polymerization. The new acrylic copolymers have a potential to obtain high dielectric constant, actuation strain, dielectric strength, and a high energy density. Silicone and ester oligomer diacrylates were also added onto the copolymer structures to suppress crystallization and to crosslink the polymer chains. Four acrylic formulations were developed with different amounts of acrylic acid. This gives a tunable stiffness, while the dielectric constant is varied from 4.3 to 7.1. The figure-of-merit performance of the best formulation is 186 % area strain, 222 MV/m of dielectric strength, and 2.7 MJ/m3 of energy density. To overcome electromechanical instability, different prestrain ratios were investigated, and under the optimized prestrain, the material has a lifetime of thousands of cycles at 120 % area strain.

  10. Synthesis and photoluminescence enhancement of nano-PAA-ZnCl2 with controllable dimension and morphology

    NASA Astrophysics Data System (ADS)

    Wu, Jianguo; Wang, Kaige; Zhou, Yukun; Wang, Shuang; Zhang, Chen; Wang, Guiren; Bai, Jintao

    2016-12-01

    One kind of ZnCl2 nano-films with controllable dimension and morphology is successfully synthesized on the top surface of nano-porous anodic alumina membrane (nano-PAAM) by self-organized method. The nano-PAA-ZnCl2 composite films are characterized by field emission scanning electron microscopy, energy dispersive spectrometer, and laser confocal Raman spectroscopy. The results indicate that the concentration of initial ZnCl2 solution, the depth of nano-PAAM substrate and the growth time of ZnCl2 crystals have important influences on the properties of nano-composite films. Furthermore, the characteristics of nano-composites such as the photoluminescence (PL) spectra are investigated. Compared with the nano-PAAM substrate, at room temperature, all of the nano-PAA-ZnCl2 composite films have both the same excitation center (335 nm) and emission center (430 nm), no matter what the nano-composite morphologies being; and the PL intensity of nano-PAA-ZnCl2 composite films are all enhanced and the maximum enhancement is two times; after annealing at 500 °C, the emission spectra of the nano-composite films stabilized at the 385 nm, 402 nm and 430 nm. The research provides a new, simple, economical and practical technology to fabricate nano-PAA composite films with higher luminousintensity.

  11. 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.

  12. 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.

  13. Styrene lower catabolic pathway in Pseudomonas fluorescens ST: identification and characterization of genes for phenylacetic acid degradation.

    PubMed

    Di Gennaro, Patrizia; Ferrara, Silvia; Ronco, Ilaria; Galli, Enrica; Sello, Guido; Papacchini, Maddalena; Bestetti, Giuseppina

    2007-08-01

    Pseudomonas fluorescens ST is a styrene degrading microorganism that, by the sequential oxidation of the vinyl side chain, converts styrene to phenylacetic acid. The cluster of styrene upper pathway catabolic genes (sty genes) has been previously localized on a chromosomal region. This report describes the isolation, sequencing and analysis of a new chromosomal fragment deriving from the ST strain genomic bank that contains the styrene lower degradative pathway genes (paa genes), involved in the metabolism of phenylacetic acid. Analysis of the paa gene cluster led to the description of 14 putative genes: a gene encoding a phenylacetyl-CoA ligase (paaF), the enzyme required for the activation of phenylacetic acid; five ORFs encoding the subunits of a ring hydroxylation multienzymatic system (paaGHIJK); the gene paaW encoding a membrane protein of unknown function; five genes for a beta-oxidation-like system (paaABCDE), involved in the steps following the aromatic ring cleavage; a gene encoding a putative permease (paaL) and a gene (paaN) probably involved in the aromatic ring cleavage. The function of some of the isolated genes has been proved by means of biotransformation experiments.

  14. Anomerization of Acrylated Glucose During Traveling Wave Ion Mobility Spectrometry

    NASA Astrophysics Data System (ADS)

    Chendo, Christophe; Moreira, Guillaume; Tintaru, Aura; Posocco, Paola; Laurini, Erik; Lefay, Catherine; Gigmes, Didier; Viel, Stéphane; Pricl, Sabrina; Charles, Laurence

    2015-09-01

    Anomerization of simple sugars in the liquid phase is known as an acid- and base-catalyzed process, which highly depends on solvent polarity. This reaction is reported here to occur in the gas phase, during traveling wave ion mobility spectrometry (TWIMS) experiments aimed at separating α- and β-anomers of penta-acrylated glucose generated as ammonium adducts in electrospray ionization. This compound was available in two samples prepared from glucose dissolved in solvents of different polarity, namely tetrahydrofuran (THF) and N,N-dimethylacetamide (DMAC), and analyzed by electrospray tandem mass spectrometry (ESI-MS/MS) as well as traveling wave ion mobility (ESI-TWIMS-MS). In MS/MS, an anchimerically-assisted process was found to be unique to the electrosprayed α-anomer, and was only observed for the THF sample. In ESI-TWIMS-MS, a signal was measured at the drift time expected for the α-anomer for both the THF and DMAC samples, in apparent contradiction to the MS/MS results, which indicated that the α-anomer was not present in the DMAC sample. However, MS/MS experiments performed after TWIMS separation revealed that ammonium adducts of the α-anomer produced from each sample, although exhibiting the same collision cross section, were clearly different. Indeed, while the α-anomer actually present in the THF sample was electrosprayed with the ammonium adducted at the C2 acrylate, its homologue only observed when the DMAC sample was subjected to TWIMS hold the adducted ammonium at the C1 acrylate. These findings were explained by a β/α inter-conversion upon injection in the TWIMS cell, as supported by theoretical calculation and dynamic molecular modeling.

  15. 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.

  16. 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

  17. Effect of anions and humic acid on the performance of nanoscale zero-valent iron particles coated with polyacrylic acid.

    PubMed

    Kim, Hong-Seok; Ahn, Jun-Young; Kim, Cheolyong; Lee, Seockheon; Hwang, Inseong

    2014-10-01

    Effects of anions (NO3(-), HCO3(-), Cl(-), SO4(2-)) and humic acid on the reactivity and core/shell chemistries of polyacrylic acid-coated nanoscale zero-valent iron (PAA-NZVI) and inorganically modified NZVI (INORG-NZVI) particles were investigated. The reactivity tests under various ion concentrations (0.2-30mN) revealed the existence of a favorable molar ratio of anion/NZVI that increased the reactivity of NZVI particles. The presence of a relatively small amount of humic acid (0.5mgL(-1)) substantially decreased the INORG-NZVI reactivity by 76%, whereas the reactivity of PAA-NZVI decreased only by 12%. The XRD and TEM results supported the role of the PAA coating of PAA-NZVI in impeding the oxidation of the Fe(0) core by groundwater solutes. This protective role provided by the organic coating also resulted in a 2.3-fold increase in the trichloroethylene (TCE) reduction capacity of PAA-NZVI compared to that of INORG-NZVI in the presence of anions/humic acid. Ethylene and ethane were simultaneously produced as the major reduction products of TCE in both NZVI systems, suggesting that a hydrodechlorination occurred without the aid of metallic catalysts. The PAA coating, originally designed to improve the mobility of NZVI, enhanced TCE degradation performances of NZVI in the presence of anions and humic acid.

  18. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true n-Alkylglutarimide/acrylic copolymers. 177.1060... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1060 n-Alkylglutarimide/acrylic copolymers. n-Alkylglutarimide/acrylic copolymers identified in this section may be safely used as...

  19. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false n-Alkylglutarimide/acrylic copolymers. 177.1060... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1060 n-Alkylglutarimide/acrylic copolymers. n-Alkylglutarimide/acrylic copolymers identified in this section may be safely used as...

  20. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false n-Alkylglutarimide/acrylic copolymers. 177.1060... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1060 n-Alkylglutarimide/acrylic copolymers. n-Alkylglutarimide/acrylic copolymers identified in this section may be safely used as...

  1. 40 CFR 721.5325 - Nickel acrylate complex.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Nickel acrylate complex. 721.5325... Substances § 721.5325 Nickel acrylate complex. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance nickel acrylate complex (PMN P-85-1034) is subject to reporting...

  2. 40 CFR 721.5325 - Nickel acrylate complex.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Nickel acrylate complex. 721.5325... Substances § 721.5325 Nickel acrylate complex. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance nickel acrylate complex (PMN P-85-1034) is subject to reporting...

  3. 40 CFR 721.5325 - Nickel acrylate complex.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Nickel acrylate complex. 721.5325... Substances § 721.5325 Nickel acrylate complex. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance nickel acrylate complex (PMN P-85-1034) is subject to reporting...

  4. 40 CFR 721.5325 - Nickel acrylate complex.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Nickel acrylate complex. 721.5325... Substances § 721.5325 Nickel acrylate complex. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance nickel acrylate complex (PMN P-85-1034) is subject to reporting...

  5. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as a food-contact surface of articles intended for...

  6. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as a food-contact surface of articles intended for...

  7. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for...

  8. 40 CFR 721.10180 - Trifunctional acrylic ester (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Trifunctional acrylic ester (generic... Specific Chemical Substances § 721.10180 Trifunctional acrylic ester (generic). (a) Chemical substance and... acrylic ester (PMN P-04-692) is subject to reporting under this section for the significant new...

  9. 40 CFR 721.10180 - Trifunctional acrylic ester (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Trifunctional acrylic ester (generic... Specific Chemical Substances § 721.10180 Trifunctional acrylic ester (generic). (a) Chemical substance and... acrylic ester (PMN P-04-692) is subject to reporting under this section for the significant new...

  10. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for...

  11. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as a food-contact surface of articles intended for...

  12. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for...

  13. 40 CFR 721.10180 - Trifunctional acrylic ester (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Trifunctional acrylic ester (generic... Specific Chemical Substances § 721.10180 Trifunctional acrylic ester (generic). (a) Chemical substance and... acrylic ester (PMN P-04-692) is subject to reporting under this section for the significant new...

  14. 21 CFR 175.210 - Acrylate ester copolymer coating.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Acrylate ester copolymer coating. 175.210 Section... COATINGS Substances for Use as Components of Coatings § 175.210 Acrylate ester copolymer coating. Acrylate ester copolymer coating may safely be used as a food-contact surface of articles intended for...

  15. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for...

  16. 40 CFR 721.10180 - Trifunctional acrylic ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Trifunctional acrylic ester (generic... Specific Chemical Substances § 721.10180 Trifunctional acrylic ester (generic). (a) Chemical substance and... acrylic ester (PMN P-04-692) is subject to reporting under this section for the significant new...

  17. 40 CFR 721.10180 - Trifunctional acrylic ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Trifunctional acrylic ester (generic... Specific Chemical Substances § 721.10180 Trifunctional acrylic ester (generic). (a) Chemical substance and... acrylic ester (PMN P-04-692) is subject to reporting under this section for the significant new...

  18. 40 CFR 721.10477 - Acrylate ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylate ester (generic). 721.10477... Substances § 721.10477 Acrylate ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as acrylate ester (PMN P-04-290) is subject...

  19. 40 CFR 721.10477 - Acrylate ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylate ester (generic). 721.10477... Substances § 721.10477 Acrylate ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as acrylate ester (PMN P-04-290) is subject...

  20. 40 CFR 721.10537 - Acrylate ester (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Acrylate ester (generic). 721.10537... Substances § 721.10537 Acrylate ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as acrylate ester (PMN P-01-579) is subject...

  1. 40 CFR 721.10537 - Acrylate ester (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Acrylate ester (generic). 721.10537... Substances § 721.10537 Acrylate ester (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as acrylate ester (PMN P-01-579) is subject...

  2. 40 CFR 721.329 - Halogenated benzyl ester acrylate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Halogenated benzyl ester acrylate... Specific Chemical Substances § 721.329 Halogenated benzyl ester acrylate (generic). (a) Chemical substance... halogenated benzyl ester acrylate (PMN P-90-1527) is subject to reporting under this section for...

  3. 21 CFR 173.5 - Acrylate-acrylamide resins.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Acrylate-acrylamide resins. 173.5 Section 173.5... CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.5 Acrylate-acrylamide resins. Acrylate-acrylamide resins may be safely used in food under the following prescribed conditions: (a)...

  4. 21 CFR 173.5 - Acrylate-acrylamide resins.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Acrylate-acrylamide resins. 173.5 Section 173.5... CONSUMPTION Polymer Substances and Polymer Adjuvants for Food Treatment § 173.5 Acrylate-acrylamide resins. Acrylate-acrylamide resins may be safely used in food under the following prescribed conditions: (a)...

  5. 40 CFR 721.324 - Alkoxylated acrylate polymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkoxylated acrylate polymer (generic... Substances § 721.324 Alkoxylated acrylate polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkoxylated acrylate...

  6. 40 CFR 721.324 - Alkoxylated acrylate polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkoxylated acrylate polymer (generic... Substances § 721.324 Alkoxylated acrylate polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkoxylated acrylate...

  7. 40 CFR 721.324 - Alkoxylated acrylate polymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkoxylated acrylate polymer (generic... Substances § 721.324 Alkoxylated acrylate polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkoxylated acrylate...

  8. 40 CFR 721.324 - Alkoxylated acrylate polymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkoxylated acrylate polymer (generic... Substances § 721.324 Alkoxylated acrylate polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkoxylated acrylate...

  9. 40 CFR 721.324 - Alkoxylated acrylate polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkoxylated acrylate polymer (generic... Substances § 721.324 Alkoxylated acrylate polymer (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkoxylated acrylate...

  10. 40 CFR 721.484 - Fluorinated acrylic copolymer (generic name).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fluorinated acrylic copolymer (generic... Specific Chemical Substances § 721.484 Fluorinated acrylic copolymer (generic name). (a) Chemical substance... fluorinated acrylic copolymer (PMN P-95-1208) is subject to reporting under this section for the...

  11. 40 CFR 721.484 - Fluorinated acrylic copolymer (generic name).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fluorinated acrylic copolymer (generic... Specific Chemical Substances § 721.484 Fluorinated acrylic copolymer (generic name). (a) Chemical substance... fluorinated acrylic copolymer (PMN P-95-1208) is subject to reporting under this section for the...

  12. 21 CFR 177.1060 - n-Alkylglutarimide/acrylic copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false n-Alkylglutarimide/acrylic copolymers. 177.1060... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1060 n-Alkylglutarimide/acrylic copolymers. n-Alkylglutarimide/acrylic copolymers identified in this section may be safely used as...

  13. 21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials,...

  14. 21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials,...

  15. 21 CFR 177.1320 - Ethylene-ethyl acrylate copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ethylene-ethyl acrylate copolymers. 177.1320... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1320 Ethylene-ethyl acrylate copolymers. Ethylene-ethyl acrylate copolymers may be safely used to produce packaging materials,...

  16. The ABC transporter ABC40 encodes a phenylacetic acid export system in Penicillium chrysogenum.

    PubMed

    Weber, Stefan S; Kovalchuk, Andriy; Bovenberg, Roel A L; Driessen, Arnold J M

    2012-11-01

    The filamentous fungus Penicillium chrysogenum is used for the industrial production of β-lactam antibiotics. The pathway for β-lactam biosynthesis has been resolved and involves the enzyme phenylacetic acid CoA ligase that is responsible for the CoA activation of the side chain precursor phenylacetic acid (PAA) that is used for the biosynthesis of penicillin G. To identify ABC transporters related to β-lactam biosynthesis, we analyzed the expression of all 48 ABC transporters present in the genome of P. chryso-genum when grown in the presence and absence of PAA. ABC40 is significantly upregulated when cells are grown or exposed to high levels of PAA. Although deletion of this transporter did not affect β-lactam biosynthesis, it resulted in a significant increase in sensitivity to PAA and other weak acids. It is concluded that ABC40 is involved in weak acid detoxification in P. chrysogenum including resistance to phenylacetic acid.

  17. Lysozyme complexes with thermo- and pH-responsive PNIPAM- b-PAA block copolymer

    NASA Astrophysics Data System (ADS)

    Pippa, Natassa; Meristoudi, Anastasia; Pispas, Stergios; Demetzos, Costas

    2017-02-01

    Lysozyme is an enzyme responsible for the damage of bacterial cell walls and is abundant in a number of secretions such as tears and human milk. In the present study, we investigated the structure, the physicochemical characteristics, and the temperature-responsiveness of lysozyme complexes with poly( N-isopropylacrylamide)- b-poly(acrylic acid) block polyelectrolyte in aqueous media. A gamut of light-scattering techniques and fluorescence spectroscopy were used in order to examine the complexation process, as well as the structure, solution behavior, and temperature response of the nanosized complexes. The concentration of copolymer polyelectrolyte was kept constant. The values of the scattering intensity, I 90, which is proportional to the mass of the species in solution, increased gradually as a function of C LYS, providing proof of the occurring complexation, while the size of the nanostructures decreased. The structure of the complexes became more open as the C LYS increased. The increase of the salinity did not affect the structural characteristics of the supramolecular nanoparticulate aggregates. On the other hand, the physicochemical and structural characteristics of the complexes changed upon increasing temperature, and the changes depended on the initial ratio block polyelectrolyte/lysozyme. The knowledge on developing block polyelectrolyte/protein complexes through electrostatic interactions, obtained from this investigation, may be applied to the design of nutraceuticals.

  18. 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...

  19. Thermodynamic Interactions between Polystyrene and Long-Chain Poly(n-Alkyl Acrylates) Derived from Plant Oils.

    PubMed

    Wang, Shu; Robertson, Megan L

    2015-06-10

    Vegetable oils and their fatty acids are promising sources for the derivation of polymers. Long-chain poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) are readily derived from fatty acids through conversion of the carboxylic acid end-group to an acrylate or methacrylate group. The resulting polymers contain long alkyl side-chains with around 10-22 carbon atoms. Regardless of the monomer source, the presence of alkyl side-chains in poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) provides a convenient mechanism for tuning their physical properties. The development of structured multicomponent materials, including block copolymers and blends, containing poly(n-alkyl acrylates) and poly(n-alkyl methacrylates) requires knowledge of the thermodynamic interactions governing their self-assembly, typically described by the Flory-Huggins interaction parameter χ. We have investigated the χ parameter between polystyrene and long-chain poly(n-alkyl acrylate) homopolymers and copolymers: specifically we have included poly(stearyl acrylate), poly(lauryl acrylate), and their random copolymers. Lauryl and stearyl acrylate were chosen as model alkyl acrylates derived from vegetable oils and have alkyl side-chain lengths of 12 and 18 carbon atoms, respectively. Polystyrene is included in this study as a model petroleum-sourced polymer, which has wide applicability in commercially relevant multicomponent polymeric materials. Two independent methods were employed to measure the χ parameter: cloud point measurements on binary blends and characterization of the order-disorder transition of triblock copolymers, which were in relatively good agreement with one another. The χ parameter was found to be independent of the alkyl side-chain length (n) for large values of n (i.e., n > 10). This behavior is in stark contrast to the n-dependence of the χ parameter predicted from solubility parameter theory. Our study complements prior work investigating the interactions between

  20. Efficient pi-facial control in the ene reaction of nitrosoarene, triazolinedione, and singlet oxygen with tiglic amides of the bornane-derived sultam as chiral auxiliary: an economical synthesis of enantiomerically pure nitrogen- and oxygen-functionalized acrylic acid derivatives.

    PubMed

    Adam, Waldemar; Degen, Hans-Georg; Krebs, Oliver; Saha-Möller, Chantu R

    2002-11-06

    The ene reaction of 4-nitronitrosobenzene (ArNO), N-phenyl-1,2,4-triazoline-3,5-dione (PTAD), and singlet oxygen (1O2) with the optically active tiglic-acid derivatives of Oppolzer's bornane-derived sultam affords the respective ene products regioselectively in excellent diastereoselectivity (de up to 99%) and in good yield (55-90%). The enophiles ArNO and PTAD give with the methyl-substituted substrate exclusively the like-configured ene adduct, while 1O2 leads to an 83:17 diastereomeric mixture. With the sterically more demanding isopropyl-substituted derivative even the smallest enophile 1O2 forms exclusively the like diastereomer. The high diastereoselectivity is rationalized in terms of the proper conformational alignment of the substrate and a preferred enophilic attack from the C(beta)-re face of the double bond. This concept offers an efficient synthetic route to enantiomerically pure nitrogen- and oxygen-functionalized acrylic acid derivatives.