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Sample records for 2-dimethylaminoethyl methacrylate dmaema

  1. Influence of polycation molecular weight on poly(2-dimethylaminoethyl methacrylate)-mediated DNA delivery in vitro.

    PubMed

    Layman, John M; Ramirez, Sean M; Green, Matthew D; Long, Timothy E

    2009-05-11

    Establishing clear structure-property-transfection relationships is a critical step in the development of clinically relevant polymers for nonviral gene therapy. In this study, we determined the influence of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) molecular weight on cytotoxicity, DNA binding, and in vitro plasmid DNA delivery efficiency in human brain microvascular endothelial cells (HBMEC). Conventional free radical polymerization was used to synthesize PDMAEMA with weight-average molecular weights ranging from 43,000 to 915,000 g/mol. MTT and LDH assays revealed that lower molecular weight PDMAEMA (M(w) = 43,000 g/mol) was slightly less toxic than higher molecular weights (M(w) > 112,000 g/mol) and that the primary mode of toxicity was cellular membrane destabilization. An electrophoretic gel shift assay revealed that all PDMAEMA molecular weights completely bound with plasmid DNA. However, heparin competitive binding experiments revealed that higher molecular weight PDMAEMA (M(w) = 915,000 g/mol) had a greater binding affinity toward plasmid DNA than lower molecular weight PDMAEMA (M(w) = 43,000 g/mol). The molecular weight of PDMAEMA was found to have a dramatic influence on transfection efficiency, and luciferase reporter gene expression increased as a function of increasing molecular weight. However, cellular uptake of polyplexes was determined to be insensitive to PDMAEMA molecular weight. In addition, our data did not correlate polyplex size with transfection efficiency. Collectively, our data suggested that the intracellular fate of the polyplexes, which involves endosomal release and DNase resistance, is more important to overall transfection efficiency than barriers to entry, such as polyplex size.

  2. Nondestructive chemical functionalization of MWNTs by poly(2-dimethylaminoethyl methacrylate) and their conjugation with CdSe quantum dots: Synthesis, properties, and cytotoxicity studies

    NASA Astrophysics Data System (ADS)

    Islam, Md. Rafiqul; Bach, Long Giang; Vo, Thanh-Sang; Tran, Thi-Nga; Lim, Kwon Taek

    2013-12-01

    Multi-walled carbon nanotubes (MWNTs) were functionalized with poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) in a nondestructive manner by UV-driven surface-initiated reversible addition fragmentation chain transfer (RAFT) polymerization. The RAFT agent having benzophenone groups was initially synthesized, and anchored to MWNTs through UV-triggered photoreaction. The subsequent RAFT polymerization of DMAEMA from the surface of MWNTs afforded PDMAEMA grafted MWNTs (MWNTs-g-PDMAEMA). The successful grafting of PDMAEMA on MWNTs via chemical linkage was confirmed by FT-IR, 1H NMR, XPS, EDX, TGA, TEM, and SEM analyses. A reversible dispersion phenomenon was observed in an aqueous solution of MWNTs-g-PDMAEMA as induced either by temperature or pH. The CdSe quantum dots (CdSe QDs) were attached to quaternized MWNTs-g-PDMAEMA to produce MWNTs-g-PDMAEMA-MeI/CdSe nanohybrids via electrostatic self-assembly. The formation of the nanohybrids was elucidated by EDS, TEM, and XRD. The cell viability assessment of the nanohybrids suggested their biocompatible character. The photoluminescence spectra of the nanohybrids indicated that the CdSe QDs significantly preserved its optical property after conjugation with MWNTs-g-PDMAEMA.

  3. Supercritical synthesis of poly (2-dimethylaminoethyl methacrylate)/ferrite nanocomposites for real-time monitoring of protein release.

    PubMed

    Bisht, Gunjan; Zaidi, M G H

    2015-06-01

    A supercritical carbon dioxide (SCC)-assisted process was developed to synthesize protein-supported poly (2-dimethylaminoethyl methacrylate)/ferrite nanocomposites (PNCs). The process involve 2,2-azobisisobutyronitrile-initiated in situ polymerization of 2-dimethylaminoethyl methacrylate in presence of ferrite nanoparticles and bisacrylamide at 90 ± 1 °C, 1200 psi over 6 h in SCC. This was followed by subsequent loading of bovine serum albumin (BSA) as a model protein over PNCs in phosphate buffer (PBS, pH 7.4) at 1200 psi, 35 ± 1 °C over additional 2 h in SCC. The formation of PNCs was ascertained through ultraviolet-visible, Fourier transform-infrared, X-ray diffraction spectra, transmission electron, atomic force microscopy and magnetometry. The developed process extends large scale production of nanomagnetic PNCs suitable as carrier for protein release applications with optimal release properties. The release of protein from PNCs under in vitro in PBS down to nanomolar range with high temporal resolution, speed and reproducibility was quantified through square wave voltammetry.

  4. Intracellular cleavable poly(2-dimethylaminoethyl methacrylate) functionalized mesoporous silica nanoparticles for efficient siRNA delivery in vitro and in vivo

    NASA Astrophysics Data System (ADS)

    Lin, Daoshu; Cheng, Qiang; Jiang, Qian; Huang, Yuanyu; Yang, Zheng; Han, Shangcong; Zhao, Yuning; Guo, Shutao; Liang, Zicai; Dong, Anjie

    2013-05-01

    A low cytotoxicity and high efficiency delivery system with the advantages of low cost and facile fabrication is needed for the application of small interfering RNA (siRNA) delivery both in vitro and in vivo. For these prerequisites, cationic polymer-mesoporous silica nanoparticles (ssCP-MSNs) were prepared by surface functionalized mesoporous silica nanoparticles with disulfide bond cross-linked poly(2-dimethylaminoethyl methacrylate) (PDMAEMA). In vitro and in vivo evaluations were performed. The synthesized ssCP-MSNs are 100-150 nm in diameter with a pore size of 10 nm and a positively charged surface with a high zeta potential of 27 mV. Consequently, the ssCP-MSNs showed an excellent binding capacity for siRNA, and an enhancement in the cell uptake and cytosolic availability of siRNA. Furthermore, the intracellular reducing cleavage of the disulfide bonds cross-linking the PDMAEMA segments led to intracellular cleavage of PDMAEMA from ssCP-MSNs, which facilitated the intracellular triggered release of siRNA. Therefore, promoted RNA interference was observed in HeLa-Luc cells, which was equal to that of Lipofectamine 2000. Significantly, compared to Lipofectamine 2000, the ssCP-MSNs were more biocompatible, with low cytotoxicity (even non-cytotoxicity) and promotion of cell proliferation to HeLa-Luc cells. The in vivo systemic distribution studies certified that ssCP-MSNs/siRNA could prolong the duration of siRNA in vivo, and that they accumulated in the adrenal gland, liver, lung, spleen, kidney, heart and thymus after intravenous injection. Encouragingly, with the ability to deliver siRNA to a tumor, ssCP-MSNs/siRNA showed a tumor suppression effect in the HeLa-Luc xenograft murine model after intravenous injection. Therefore, the ssCP-MSNs cationic polymer-mesoporous silica nanoparticles with low cytotoxicity are promising for siRNA delivery.A low cytotoxicity and high efficiency delivery system with the advantages of low cost and facile fabrication is needed

  5. Effect of glycounits on the antimicrobial properties and toxicity behavior of polymers based on quaternized DMAEMA.

    PubMed

    Álvarez-Paino, Marta; Muñoz-Bonilla, Alexandra; López-Fabal, Fátima; Gómez-Garcés, José L; Heuts, Johan P A; Fernández-García, Marta

    2015-01-12

    Polymers with quaternary ammonium groups such as quaternized poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMAQ) have been used as antimicrobial agents because of their demonstrated good antimicrobial activities against a huge number and types of microbes, although their cytotoxicity is also well-known. In this work block copolymers based on PDMAEMAQ were synthesized containing hydrophobic segments of poly(butyl methacrylate) to improve the antimicrobial activity and glycomonomer units with the aim of decreasing the cytotoxicity of the polymers. Hydrophobic butyl methacrylate (BMA) blocks were chain extended by statistical and block copolymers of DMAEMA and 2-{[(d-glucosamin-2-N-yl)carbonylethyl methacrylate (HEMAGl) glycomonomer of different compositions. In order to find the balance between antimicrobial activity and cytotoxicity, the selectivity index of each polymer was obtained from minimum inhibitory concentrations (MIC) and white and red blood cells toxicity measurements. PMID:25438196

  6. Effects of quaternization on the morphological stability and antibacterial activity of electrospun poly(DMAEMA-co-AMA) nanofibers.

    PubMed

    Xu, Jing-Wei; Wang, Yao; Yang, Yun-Feng; Ye, Xiang-Yu; Yao, Ke; Ji, Jian; Xu, Zhi-Kang

    2015-09-01

    Electrospun nanofibers with antibacterial activity are greatly promising for medical treatment and water purification. Herein we report antibacterial nanofibers electrospun from a series of poly(dimethylamino ethyl methacrylate-co-alkyl methacrylates) (poly(DMAEMA-co-AMA)) and to distinguish the effects of free and cross-linked cations derived from quanternization on the antibacterial activity. Poly(DMAEMA-co-AMA)s are simply synthesized by free radical polymerization from commercial monomers. DSC analysis indicates that they have Tg lower than room temperature and thus the electrospun nanofibers adhere to each other and evenly tend to form films, instead of keeping cylinderic shape. Benzyl chloride (BC) and p-xylylene dichloride (XDC) can quaternize DMAEMA units and to generate cations on the nanofiber surface. XPS analysis and colorimetric assay determine the quaternization degree and the surface accessible quaternary amines (N(+)), respectively. It is very promising that this quaternization endows the electrospun nanofibers with both stable morphology and antibacterial activity. The BC-quaternized fibers show better antibacterial behavior against Escherichia coli and Staphylococcus aureus than those of the XDC-quaternized/cross-linked ones, because cross-linking suppresses the chain mobility of cations. Our results confirm that antibacterial nanofibers can be facilely prepared and chain mobility of the formed cations is the necessary prerequisite for their antibacterial activity.

  7. Novel stimuli responsive gellan gum-graft-poly(DMAEMA) hydrogel as adsorbent for anionic dye.

    PubMed

    Karthika, J S; Vishalakshi, B

    2015-11-01

    In this study, gellan gum-grafted-poly((2-dimethylamino) ethyl methacrylate) (GG-g-poly(DMAEMA)) hydrogel was made by free radical polymerization in aqueous media employing microwave irradiation technique. Ammonium persulfate (APS)/N,N,N',N'-tetramethylethylenediamine (TMEDA) were used as initiator-accelerator pair. N,N'-methylenebisacrylamide (MBA) has been used as crosslinker. The gel was characterized by FTIR, XRD, TGA, DSC and SEM techniques. The characteristic peaks at 1724, 2630, 1147, 1650 and 1535cm(-1) in the IR spectrum confirms grafting and gel formation. The TGA data reveals that synthesized gels were thermally more stable than gellan gum. The XRD studies confirm the crystalline nature of the synthesized material. Swelling behaviour of the hydrogel under different temperatures and pH conditions was investigated. The results indicated drastic changes in swelling around pH 7.0 and 50°C. The gels were evaluated as an adsorbent to remove an anionic dye, methyl orange (MO), from aqueous solution. The pH conditions for maximum adsorption were optimized, the adsorption data is observed to fit best to the Freundlich isotherm model and the maximum adsorption capacity was found to be 25.8mgg(-1). The kinetic analysis revealed a second-order adsorption process. The thermodynamic parameters showed the adsorption to be exothermic and non-spontaneous at high temperatures.

  8. Novel stimuli responsive gellan gum-graft-poly(DMAEMA) hydrogel as adsorbent for anionic dye.

    PubMed

    Karthika, J S; Vishalakshi, B

    2015-11-01

    In this study, gellan gum-grafted-poly((2-dimethylamino) ethyl methacrylate) (GG-g-poly(DMAEMA)) hydrogel was made by free radical polymerization in aqueous media employing microwave irradiation technique. Ammonium persulfate (APS)/N,N,N',N'-tetramethylethylenediamine (TMEDA) were used as initiator-accelerator pair. N,N'-methylenebisacrylamide (MBA) has been used as crosslinker. The gel was characterized by FTIR, XRD, TGA, DSC and SEM techniques. The characteristic peaks at 1724, 2630, 1147, 1650 and 1535cm(-1) in the IR spectrum confirms grafting and gel formation. The TGA data reveals that synthesized gels were thermally more stable than gellan gum. The XRD studies confirm the crystalline nature of the synthesized material. Swelling behaviour of the hydrogel under different temperatures and pH conditions was investigated. The results indicated drastic changes in swelling around pH 7.0 and 50°C. The gels were evaluated as an adsorbent to remove an anionic dye, methyl orange (MO), from aqueous solution. The pH conditions for maximum adsorption were optimized, the adsorption data is observed to fit best to the Freundlich isotherm model and the maximum adsorption capacity was found to be 25.8mgg(-1). The kinetic analysis revealed a second-order adsorption process. The thermodynamic parameters showed the adsorption to be exothermic and non-spontaneous at high temperatures. PMID:26325677

  9. pH- and Temperature-Responsive P(DMAEMA-GMA)-Alginate Semi-IPN Hydrogels Formed by Radical and Ring-Opening Polymerization for Aminophylline Release.

    PubMed

    Gao, Chunmei; Liu, Mingzhu; Chen, Jun; Chen, Chen

    2012-01-01

    A novel poly((2-dimethylamino) ethyl methacrylate-glycidyl methacrylate)-alginate (P(DMAEMA-GMA)alginate) semi-IPN hydrogel was synthesized via radical polymerization of the double bonds and ring-opening of the epoxy groups without using catalyst and cross-linker. (1)H-NMR, FT-IR and DSC data were consistent with the expected structures for the hydrogels. The interior morphology of the hydrogels was also investigated by SEM. The swelling ratio and compressive strength of the hydrogels were measured. The semi-IPN hydrogel had pH and temperature sensitivity, and pH-sensitive points of all hydrogels were found to be at pH 5.0. The release behavior of the model drug, aminophylline, was found to be dependent on the hydrogel composition and environment pH, which manifests that these materials have potential applications as intelligent drug carriers. PMID:21513583

  10. Polymer-induced fractal patterns of [60]fullerene containing poly(methacrylic acid) in salt solutions.

    PubMed

    Tan, Chung How; Ravi, Palaniswamy; Dai, Sheng; Tam, Kam Chiu

    2004-11-01

    Well-defined water-soluble pH-responsive [60]fullerene (C60) containing poly(methacrylic acid) (PMAA-b-C60) was synthesized using the atom transfer radical polymerization technique. By varying pH and salt concentration, different types of fractal patterns at nano- to microscopic dimensions were observed for negatively charged PMAA-b-C60, while such structure was not observed for positively charged poly(2-dimethylaminoethyl methacrylate)-b-C60. We demonstrated that negatively charged fullerene containing polymeric systems can serve as excellent nanotemplates for the controlled growth of inorganic crystals at the nano- to micrometer length scale, and the possible mechanism was proposed.

  11. Pentablock copolymers of pluronic F127 and modified poly(2-dimethyl amino)ethyl methacrylate for internalization mechanism and gene transfection studies

    PubMed Central

    Huang, Shih-Jer; Wang, Tzu-Pin; Lue, Sheng-I; Wang, Li-Fang

    2013-01-01

    Cationic polymers are one of the major nonviral gene delivery vectors investigated in the past decade. In this study, we synthesized several cationic copolymers using atom transfer radical polymerization (ATRP) for gene delivery vectors: pluronic F127-poly(dimethylaminoethyl methacrylate) (PF127-pDMAEMA), pluronic F127-poly (dimethylaminoethyl methacrylate-tert-butyl acrylate) (PF127-p(DMAEMA-tBA)), and pluronic F127-poly(dimethylaminoethyl methacrylate-acrylic acid) (PF127-p(DMAEMA-AA)). The copolymers showed high buffering capacity and efficiently complexed with plasmid deoxyribonucleic acid (pDNA) to form nanoparticles 80–180 nm in diameter and with positive zeta potentials. In the absence of 10% fetal bovine serum, PF127-p(DMAEMA-AA) showed the highest gene expression and the lowest cytotoxicity in 293T cells. After acrylic acid groups had been linked with a fluorescent dye, the confocal laser scanning microscopic image showed that PF127-p(DMAEMA-AA)/pDNA could efficiently enter the cells. Both clathrin-mediated and caveolae-mediated endocytosis mechanisms were involved. Our results showed that PF127-p(DMAEMA-AA) has great potential to be a gene delivery vector. PMID:23745045

  12. Ammonium methacrylate

    Integrated Risk Information System (IRIS)

    Ammonium methacrylate ; CASRN 16325 - 47 - 6 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 Noncarcin

  13. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    Methyl methacrylate ; CASRN 80 - 62 - 6 ( 03 / 02 / 98 ) 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 f

  14. Quaternized dimethylaminoethyl methacrylate strong base anion exchange fibers for As(V) adsorption

    NASA Astrophysics Data System (ADS)

    Kavaklı, Cengiz; Akkaş Kavaklı, Pınar; Turan, Burcu Dila; Hamurcu, Aslı; Güven, Olgun

    2014-09-01

    N,N-Dimethylaminoethyl methacrylate (DMAEMA) grafted polyethylene/polypropylene (PE/PP) nonwoven fibers (DMAEMA-g-PE/PP) was prepared by radiation-induced graft polymerization. DMAEMA graft chains on nonwoven fibers were quaternized with dimethyl sulfate solution for the preparation of strong base anion exchange fibers (QDMAEMA-g-PE/PP). Fiber structures were characterized by FTIR, XPS and SEM techniques. The effect of solution pH, contact time, initial As(V) ion concentration and coexisting ions on the As(V) adsorption capacity of the QDMAEMA-g-PE/PP fibers were investigated by performing batch adsorption experiments. The adsorption of As(V) by QDMAEMA-g-PE/PP fibers was found to be independent on solution pH in the range 4.00-10.00. Kinetic experiments show that the As(V) adsorption rate was rapid and As(V) adsorption follows pseudo second-order kinetic model. As(V) adsorption equilibrium data were analyzed using Langmuir and Freundlich adsorption isotherm model equations. Langmuir and Freundlich adsorption isotherm models fitted the experimental data well. The maximum adsorption capacity (qmax) calculated from Langmuir isotherm was found to be 83.33 mg As(V)/g polymer at pH 7.00. The adsorbent was used for three cycles without significant loss of adsorption capacity. The adsorbed As(V) ions were desorbed effectively by a 0.1 M NaOH solution.

  15. Fabrication of flexible, transparent and conductive films from single-walled carbon nanotubes with high aspect ratio using poly((furfuryl methacrylate)-co-(2-(dimethylamino)ethyl methacrylate)) as a new polymeric dispersant

    NASA Astrophysics Data System (ADS)

    Lee, Taeheon; Kim, Byunghee; Kim, Sumin; Han, Jong Hun; Jeon, Heung Bae; Lee, Young Sil; Paik, Hyun-Jong

    2015-04-01

    We synthesized poly((furfuryl methacrylate)-co-(2-(dimethylamino)ethyl methacrylate)) (p(FMA-co-DMAEMA)) for the dispersion of single-walled carbon nanotubes (SWCNTs) while maintaining their high aspect ratios. The nanotubes' length and height were 2.0 μm and 2 nm, as determined by transmission electron microscopy and atomic force microscopy, respectively. Transparent conductive films (TCFs) were fabricated by individually dispersed long SWCNTs onto a flexible polyethylene terephthalate substrate. The sheet resistance (Rs) was 210 Ω □-1 with 81% transmittance at a wavelength of 550 nm. To reduce their Rs, the TCFs were treated with HNO3 and SOCl2. After treatment, the TCFs had an Rs of 85.75 Ω □-1 at a transmittance of 85%. The TCFs exhibited no appreciable change over 200 repeated bending cycles. Dispersing SWCNTs with this newly synthesized polymer is an effective way to fabricate a transparent, highly conductive and flexible film.

  16. Radiation-induced graft copolymerization of dimethylaminoethyl methacrylate onto graphene oxide for Cr(VI) removal

    NASA Astrophysics Data System (ADS)

    Ma, Hui-Ling; Zhang, Youwei; Zhang, Long; Wang, Liancai; Sun, Chao; Liu, Pinggui; He, Lihua; Zeng, Xinmiao; Zhai, Maolin

    2016-07-01

    Dimethylaminoethyl methacrylate (DMAEMA)-grafted graphene oxide hybrid materials (GO-g-P) were fabricated using γ-ray irradiation at ambient temperature. The morphology and structure of GO-g-P were characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron (XPS), thermogravimetric analysis (TGA) and X-ray diffraction (XRD). It was confirmed that DMAEMA was grafted successfully on the surface of graphene sheet. The grafting yield of GO-g-P increased with monomer concentration (0-2.5 mol L-1) and dose (0-40 kGy). The resulting adsorbent (GO-g-P) with amine groups was highly efficient for removing Cr(VI) from its acidic aqueous solution and could be easily separated by filtration. The optimum pH for Cr(VI) removal was observed at pH 1.1 and the Cr(VI) uptake of GO-g-P at this pH was 82.4 mg g-1.

  17. Thermoforming polymethyl methacrylate.

    PubMed

    Jagger, R G; Okdeh, A

    1995-11-01

    This study characterized a range of commercially available polymethyl methacrylate sheets with respect to molecular weight, residual monomer content, and glass transition temperature and then developed a thermoforming procedure that produced visually satisfactory thermoformed polymethyl methacrylate specimens. Molecular weight values of Perspex material were considerably greater than those of the other materials. All materials but Diakon had residual monomer concentrations of less than 1% and glass transition temperature values greater than 100 degrees C. Perspex material was selected for further investigation. It was necessary to preheat Perspex sheets in an oven at 160 degrees C for at least 30 minutes before heating and forming on the thermoforming apparatus to obtain acceptable specimens.

  18. Radiation synthesis of poly[(dimethylaminoethyl methacrylate)-co-(ethyleneglycol dimethacrylate)] hydrogels and its application as a carrier for anticancer delivery

    NASA Astrophysics Data System (ADS)

    Mazied, Nabila A.; Ismail, Sahar A.; Abou Taleb, Manal F.

    2009-11-01

    The use of hydrogels as carriers for anticancer delivery has been a subject of significant recent research. In our recent work, we have shown that diffusion-controlled delivery of flutamide from hydrogels containing poly (dimethylaminoethyl methacrylate (DMAEMA)/ethyleneglycol dimethacrylate (EGDMA)) can be possible and controlled by the three-dimensional structure. Hydrogels based essentially on dimethylaminoethyl methacrylate and different ratios of ethyleneglycol dimethacrylate monomers were synthesized using gamma radiation copolymerization. The influence of copolymer composition and pH value of the surrounding medium on swelling behavior into the glassy polymer were discussed. The results showed that the ratio of EGDMA in the comonomer feeding solution has a great effect on the gel fraction and water content in the final hydrogel. In this regard, it was observed that the increase of EGDMA ratio decreased these properties. The ability of the prepared copolymer to be used as drug carrier for anticancer drug-delivery system was estimated using flutamide as a model drug. In vitro drug-release studies in different buffer solutions show that the basic parameters affecting the drug release behavior of hydrogel are the pH of the solution and DMAEMA content of hydrogel.

  19. Development of dental restorative materials based on visible light-cured multi-methacrylates

    NASA Astrophysics Data System (ADS)

    Tiba, Amer

    The studies described in this dissertation focus on new visible light-curing (VLC) oligomers exhibiting low shrinkage, low water sorption, and improved mechanical properties. A family of multi-methacrylates, based on poly(isopropylidenediphenol) resin (BPA), was synthesized, characterized, and evaluated. The commercial BPA resin is prepared from enzymatic polymerization (oligomerization) of bisphenol A. The BPA resin, having an average of eight phenolic hydroxyl groups per molecule, was treated with propylene carbonate, and the resultant product, i.e., propoxylated BPA (PEBPA) oligomer, was confirmed by Fourier transform infrared spectroscopy (FT-IR) and sp{13}C nuclear magnetic resonance (NMR). The propoxylated BPA was subsequently treated with methacryloyl chloride to produce the multi-methacrylates, identified by FT-IR and NMR. The PEBPA oligomer multimethacrylate: triethylene glycol dimethacrylate (TEGDMA) (50:50/wt:wt) blends were combined with 0.5 wt. % camphoroquinone (CQ) and 1.0 wt. % N,N-dimethylaminoethyl methacrylate (DMAEMA). The control polymers were 2,2-bis(4-(2-hydroxy-3-methacryloyloxypropoxy)phenyl) propane (BisGMA): TEGDMA(50:50/wt:wt) blends having the same levels of CQ/DMAEMA. Differential photocalorimetry (DPC) and differential scanning calorimetry (DSC) showed these multimethacrylate/TEGDMA (neat resin) blends have polymerization characteristics comparable to the BisGMA/TEGDMA controls. These new multifunctional oligomers have lower polymerization shrinkage and lower uptake of water and other liquids, compared to BisGMA based materials. In addition, two experimental oligomers, PEBPA #2 and #3, have higher compressive strength than the BisGMA control. A biocompatibility test of the polymerized multi-methacrylate resins was performed and compared with the conventional BisGMA/TEGDMA resin and blank controls, using cell culture techniques. Human gingival fibroblasts were used for biocompatibility evaluation of these resins. The results revealed

  20. Recyclable antibacterial magnetic nanoparticles grafted with quaternized poly(2-(dimethylamino)ethyl methacrylate) brushes.

    PubMed

    Dong, Hongchen; Huang, Jinyu; Koepsel, Richard R; Ye, Penglin; Russell, Alan J; Matyjaszewski, Krzysztof

    2011-04-11

    Highly efficient recyclable antibacterial magnetite nanoparticles consisting of a magnetic Fe(3)O(4) core with an antibacterial poly(quaternary ammonium) (PQA) coating were prepared in an efficient four-step process. The synthetic pathway included: (1) preparation of Fe(3)O(4) nanoparticles via coprecipitation of Fe(2+)/Fe(3+) in the presence of an alkaline solution; (2) attachment of an ATRP initiating functionality to the surface of the nanoparticles; (3) surface-initiated atom transfer radical polymerization (ATRP) of 2-(dimethylamino)ethyl methacrylate (DMAEMA); and (4) transformation of PDMAEMA brushes to PQA via quaternization with ethyl bromide. The success of the surface functionalization was confirmed by FT-IR, thermal gravimetric analysis (TGA), elemental analysis, and transmission electron microscopy (TEM). The PQA-modified magnetite nanoparticles were dispersed in water and exhibited a response to an external magnetic field, making the nanoparticles easy to remove from water after antibacterial tests. The PQA-modified magnetite nanoparticles retained 100% biocidal efficiency against E. coli (10(5) to 10(6)E. coli/mg nanoparticles) during eight exposure/collect/recycle procedures without washing with any solvents or water.

  1. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  2. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  3. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate... generically as polymers of styrene, cyclohexyl methacrylate and substituted methacrylate (PMNs...

  4. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  5. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  6. 40 CFR 721.10153 - Modified methyl methacrylate, 2-hydroxyethyl methacrylate polymer (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hydroxyethyl methacrylate polymer (generic). 721.10153 Section 721.10153 Protection of Environment...-hydroxyethyl methacrylate polymer (generic). (a) Chemical substance and significant new uses subject to... methacrylate polymer (PMN P-08-6) is subject to reporting under this section for the significant new...

  7. Amphiphilic poly(D- or L-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) block copolymers: controlled synthesis, characterization, and stereocomplex formation.

    PubMed

    Spasova, Mariya; Mespouille, Laetitia; Coulembier, Olivier; Paneva, Dilyana; Manolova, Nevena; Rashkov, Iliya; Dubois, Philippe

    2009-05-11

    Novel well-defined amphiphilic poly(D-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PDLA-b-PDMAEMA) and poly(L-lactide)-b-poly(N,N-dimethylamino-2-ethyl methacrylate) (PLLA-b-PDMAEMA) copolymers were obtained. The synthesis strategy consisted of a three-step procedure: (i) controlled ring-opening polymerization (ROP) of (D- or L-)lactide initiated by Al(O(i)Pr)(3), followed by (ii) quantitative conversion of the polylactide (PLA) hydroxyl end-groups with bromoisobutyryl bromide and (iii) atom transfer radical polymerization (ATRP) of DMAEMA. The PLA block molecular weight was kept below 5000 g/mol. The macromolecular parameters of the (co)polymers were determined by (1)H NMR spectroscopy and size exclusion chromatography (SEC). The stereocomplexes of PDLA-b-PDMAEMA/PLLA-b-PDMAEMA diblock copolymers were prepared via solvent casting. The stereocomplex formation was evidenced by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analyses. The obtained stereocomplexes had melting temperature of about 65 degrees C above that of the individual copolymers and exhibited diffraction patterns assigned to the stereocomplex crystallites. In addition, for the first time it was shown that the replacement of one of the PLA partners with high molecular weight PLLA or PDLA did not hamper the stereocomplex formation. The presence of PDMAEMA blocks proved to impart hydrophilicity of the synthesized copolymers and related stereocomplexes, as determined by static water contact angle measurements. PMID:19331403

  8. Phase holograms in polymethyl methacrylate

    NASA Technical Reports Server (NTRS)

    Maker, P. D.; Muller, R. E.

    1992-01-01

    A procedure is described for the fabrication of complex computer-generated phase holograms in polymethyl methacrylate (PMMA) by means of partial-exposure e-beam lithography and subsequent carefully controlled partial development. Following the development, the pattern appears (rendered in relief) in the PMMA, which then acts as the phase-delay medium. The devices fabricated were designed with 16 equal phase steps per retardation cycle, were up to 3 mm square, and consisted of up to 10 millions of 0.3-2.0-micron square pixels. Data files were up to 60 Mb-long, and the exposure times ranged to several hours. A Fresnel phase lens was fabricated with a diffraction-limited optical performance of 83-percent efficiency.

  9. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may... produced by the polymerization of methacrylic acid and divinylbenzene. The divinylbenzene functions as...

  10. Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

    PubMed

    Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

    2012-01-01

    Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer.

  11. Methacrylated glycol chitosan as a photopolymerizable biomaterial.

    PubMed

    Amsden, Brian G; Sukarto, Abby; Knight, Darryl K; Shapka, Stephen N

    2007-12-01

    Glycol chitosan is a derivative of chitosan that is soluble at neutral pH and possesses potentially useful biological properties. With the goal of obtaining biocompatible hydrogels for use as tissue engineering scaffolds or drug delivery depots, glycol chitosan was converted to a photopolymerizable prepolymer through graft methacrylation using glycidyl methacrylate in aqueous media at pH 9. N-Methacrylation was verified by both (1)H NMR and (13)C NMR. The degree of N-methacrylation, measured via (1)H NMR, was easily varied from 1.5% to approximately 25% by varying the molar ratio of glycidyl methacrylate to glycol chitosan and the reaction time. Using a chondrocyte cell line, the N-methacrylated glycol chitosan was found to be noncytotoxic up to a concentration of 1 mg/mL. The prepolymer was cross-linked in solution using UV light and Irgacure 2959 photoinitiator under various conditions to yield gels of low sol content ( approximately 5%), high equilibrium water content (85-95%), and thicknesses of up to 6 mm. Cross-polarization magic-angle spinning (13)C solid state NMR verified the complete conversion of the double bonds in the gel. Chondrocytes seeded directly onto the gel surface, populated the entirety of the gel and remained viable for up to one week. The hydrogels degraded slowly in vitro in the presence of lysozyme at a rate that increased as the cross-link density of the gels decreased. PMID:18031015

  12. Photolithography with polymethyl methacrylate (PMMA)

    NASA Astrophysics Data System (ADS)

    Carbaugh, Daniel J.; Wright, Jason T.; Parthiban, Rajan; Rahman, Faiz

    2016-02-01

    Polymethyl methacrylate (PMMA) is widely used as an electron beam resist but is not used as a photoresist because of its insensitivity to electromagnetic radiation with wavelengths longer than about 300 nm. In this paper we describe a technique for performing conventional photolithography with high molecular weight PMMA at the widely used 365 nm i-line wavelength. The technique involves photosensitizing PMMA with Irgacure 651—a commercially available photo-initiator that can cause PMMA strands to cross-link. Optimum amount of Irgacure can produce a negative tone photoresist with adequate photosensitivity and plasma etch resistance. We describe this technique in detail with complete processing conditions and discuss the effects of varying Irgacure 651 concentration in PMMA as well as changes in UV exposure dose. We also show example structures patterned with commonly available materials and equipment. Finally, we show that it is possible to carry out gradient lithography with this approach, in order to produce structures in relief in photosensitive PMMA.

  13. Polymethyl methacrylate microspheres in collagen.

    PubMed

    Haneke, Eckart

    2004-12-01

    Artecoll was developed about 20 years ago and underwent a number of production changes until it recently became FDA approved under the new name of Artefill. This product contains 20% polymethyl methacrylate (PMMA) microspheres with a diameter of 30 to 40 microm, which are suspended in a 3.5% atelo-collagen solution. The PMMA microspheres are now purified and no longer have an electrostatic charge, which in part was the cause for the early granulomatous reactions. Further, PMMA has long been known as bone cement and has been used in cosmetic surgery with a very good safety record. PMMA microspheres are biologically inert and nondegradable. The treatment results are therefore permanent and technical errors as well as incorrect injections will last. Due to the early record of granuloma formation, there is still a debate as to whether this product-as well as all other permanent fillers-should be injected for cosmetic reasons or not. With proper indications, excellent injection techniques, and realistic expectations as to what can be expected, this product has now proved to be one of the superior permanent filler substances.

  14. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  15. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  16. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  17. 40 CFR 721.9492 - Polymers of styrene, cyclohexyl methacrylate and substituted methacrylate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Polymers of styrene, cyclohexyl... Significant New Uses for Specific Chemical Substances § 721.9492 Polymers of styrene, cyclohexyl methacrylate...) The chemical substances identified generically as polymers of styrene, cyclohexyl methacrylate...

  18. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  19. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  20. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  1. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  2. 21 CFR 882.5300 - Methyl methacrylate for cranioplasty.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate for cranioplasty. (a) Identification. Methyl methacrylate for cranioplasty (skull repair) is a self-curing acrylic that a surgeon uses to repair a skull defect in a patient. At the time of...

  3. Grafting of N,N-dimethylaminoethyl methacrylate from PE/PP nonwoven fabric via radiation-induced RAFT polymerization and quaternization of the grafts

    NASA Astrophysics Data System (ADS)

    Madrid, Jordan F.; Barsbay, Murat; Abad, Lucille; Güven, Olgun

    2016-07-01

    Radiation induced grafting method is one of the most promising grafting techniques and it works successfully together with the reversible addition fragmentation chain transfer (RAFT) polymerization, one of the most prominent controlled free-radical polymerization (CRP) methods. This study reports grafting of N,N-dimethylaminoethyl methacrylate (DMAEMA) from the surface of polyethylene/polypropylene nonwoven fabric (PE/PP NWF) by the combination of radiation-induced initiation and the RAFT polymerization technique. Effects of monomer concentration, absorbed dose and solvent choice on the grafting yield have been investigated. The grafted NWF's were characterized by ATR-FTIR, XPS, SEM, EDX and thermal analysis methods. The results indicated that surface properties were completely altered after grafting compared to pristine PE/PP even for those with very low degree of PDMAEMA grafting. Free homopolymers in solution have been analyzed by GPC in order to obtain information about the grafts. The PDMAEMA grafts on the fabric surfaces were later quaternized with dimethyl sulfate to yield positively charged surfaces that were tested for antibacterial properties.

  4. pH-sensitive methacrylic copolymers and the production thereof

    SciTech Connect

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2006-02-14

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  5. pH-sensitive methacrylic copolymers and the production thereof

    SciTech Connect

    Mallapragada, Surya K.; Anderson, Brian C.; Bloom, Paul D.; Sheares Ashby, Valerie V.

    2007-01-09

    The present invention provides novel multi-functional methacrylic copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility under acidic conditions. The copolymers are constructed from tertiary amine methacrylates and poly(ethylene glycol) containing methacrylates. The copolymers are useful as gene vectors, pharmaceutical carriers, and in protein separation applications.

  6. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the...

  7. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the...

  8. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methacrylic acid-divinylbenzene copolymer. 172.775... HUMAN CONSUMPTION Other Specific Usage Additives § 172.775 Methacrylic acid-divinylbenzene copolymer. Methacrylic acid-divinylbenzene copolymer may be safely used in food in accordance with the...

  9. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization.

    PubMed

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao

    2014-12-10

    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  10. Electrospun regenerated cellulose nanofibrous membranes surface-grafted with polymer chains/brushes via the atom transfer radical polymerization method for catalase immobilization.

    PubMed

    Feng, Quan; Hou, Dayin; Zhao, Yong; Xu, Tao; Menkhaus, Todd J; Fong, Hao

    2014-12-10

    In this study, an electrospun regenerated cellulose (RC) nanofibrous membrane with fiber diameters of ∼200-400 nm was prepared first; subsequently, 2-hydroxyethyl methacrylate (HEMA), 2-dimethylaminoethyl methacrylate (DMAEMA), and acrylic acid (AA) were selected as the monomers for surface grafting of polymer chains/brushes via the atom transfer radical polymerization (ATRP) method. Thereafter, four nanofibrous membranes (i.e., RC, RC-poly(HEMA), RC-poly(DMAEMA), and RC-poly(AA)) were explored as innovative supports for immobilization of an enzyme of bovine liver catalase (CAT). The amount/capacity, activity, stability, and reusability of immobilized catalase were evaluated, and the kinetic parameters (Vmax and Km) for immobilized and free catalase were determined. The results indicated that the respective amounts/capacities of immobilized catalase on RC-poly(HEMA) and RC-poly(DMAEMA) nanofibrous membranes reached 78 ± 3.5 and 67 ± 2.7 mg g(-1), which were considerably higher than the previously reported values. Meanwhile, compared to that of free CAT (i.e., 18 days), the half-life periods of RC-CAT, RC-poly(HEMA)-CAT, RC-poly(DMAEMA)-CAT, and RC-poly(AA)-CAT were 49, 58, 56, and 60 days, respectively, indicating that the storage stability of immobilized catalase was also significantly improved. Furthermore, the immobilized catalase exhibited substantially higher resistance to temperature variation (tested from 5 to 70 °C) and lower degree of sensitivity to pH value (tested from 4.0 and 10.0) than the free catalase. In particular, according to the kinetic parameters of Vmax and Km, the nanofibrous membranes of RC-poly(HEMA) (i.e., 5102 μmol mg(-1) min(-1) and 44.89 mM) and RC-poly(DMAEMA) (i.e., 4651 μmol mg(-1) min(-1) and 46.98 mM) had the most satisfactory biocompatibility with immobilized catalase. It was therefore concluded that the electrospun RC nanofibrous membranes surface-grafted with 3-dimensional nanolayers of polymer chains/brushes would be

  11. Dimensional accuracy of thermoformed polymethyl methacrylate.

    PubMed

    Jagger, R G

    1996-12-01

    Thermoforming of polymethyl methacrylate sheet is used to produce a number of different types of dental appliances. The purpose of this study was to determine the dimensional accuracy of thermoformed polymethyl methacrylate specimens. Five blanks of the acrylic resin were thermoformed on stone casts prepared from a silicone mold of a brass master die. The distances between index marks were measured both on the cast and on the thermoformed blanks with an optical comparator. Measurements on the blanks were made again 24 hours after processing and then 1 week, 1 month, and 3 months after immersion in water. Linear shrinkage of less than 1% (range 0.37% to 0.52%) was observed 24 hours after removal of the blanks from the cast. Immersion of the thermoformed specimens in water resulted in an increase in measured dimensions, but after 3 months' immersion these increases were still less than those of the cast (range 0.07% to 0.18%). It was concluded that it is possible to thermoform Perspex polymethyl methacrylate accurately.

  12. The mechanical properties of elastomeric poly(alkyl methacrylate)s.

    PubMed

    Davy, K W; Braden, M

    1987-09-01

    A range of poly(alkyl methacrylate)s in the range C5 to C13 with varying degrees of crosslinking, have been studied with respect to stress-strain behaviour. Where the extensions to break were sufficiently high, stress-strain properties conformed well to the statistical theory of rubber elasticity, the Mooney/Rivlin C2 term being sensibly zero. All materials studied were very elastic, exhibiting extremely little permanent set. The energy to break decreases very rapidly as the homologous series is ascended, and 0.5% crosslinking agent is perfectly adequate to give elastic properties. Hence either n-pentyl or hexyl methacrylates are to be preferred in soft prosthesis formulations on mechanical grounds.

  13. Zwitterionic Poly(amino acid methacrylate) Brushes

    PubMed Central

    2014-01-01

    A new cysteine-based methacrylic monomer (CysMA) was conveniently synthesized via selective thia-Michael addition of a commercially available methacrylate-acrylate precursor in aqueous solution without recourse to protecting group chemistry. Poly(cysteine methacrylate) (PCysMA) brushes were grown from the surface of silicon wafers by atom-transfer radical polymerization. Brush thicknesses of ca. 27 nm were achieved within 270 min at 20 °C. Each CysMA residue comprises a primary amine and a carboxylic acid. Surface zeta potential and atomic force microscopy (AFM) studies of the pH-responsive PCysMA brushes confirm that they are highly extended either below pH 2 or above pH 9.5, since they possess either cationic or anionic character, respectively. At intermediate pH, PCysMA brushes are zwitterionic. At physiological pH, they exhibit excellent resistance to biofouling and negligible cytotoxicity. PCysMA brushes undergo photodegradation: AFM topographical imaging indicates significant mass loss from the brush layer, while XPS studies confirm that exposure to UV radiation produces surface aldehyde sites that can be subsequently derivatized with amines. UV exposure using a photomask yielded sharp, well-defined micropatterned PCysMA brushes functionalized with aldehyde groups that enable conjugation to green fluorescent protein (GFP). Nanopatterned PCysMA brushes were obtained using interference lithography, and confocal microscopy again confirmed the selective conjugation of GFP. Finally, PCysMA undergoes complex base-catalyzed degradation in alkaline solution, leading to the elimination of several small molecules. However, good long-term chemical stability was observed when PCysMA brushes were immersed in aqueous solution at physiological pH. PMID:24884533

  14. 40 CFR 721.10397 - Alkyl acrylate-polyfluoro methacrylate-poly(oxyalkylenediyl)-methacrylates (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl acrylate-polyfluoro methacrylate... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10397 Alkyl acrylate-polyfluoro... subject to reporting. (1) The chemical substances identified generically as alkyl...

  15. 40 CFR 721.10397 - Alkyl acrylate-polyfluoro methacrylate-poly(oxyalkylenediyl)-methacrylates (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl acrylate-polyfluoro methacrylate... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10397 Alkyl acrylate-polyfluoro... subject to reporting. (1) The chemical substances identified generically as alkyl...

  16. 40 CFR 721.10397 - Alkyl acrylate-polyfluoro methacrylate-poly(oxyalkylenediyl)-methacrylates (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl acrylate-polyfluoro methacrylate... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10397 Alkyl acrylate-polyfluoro... subject to reporting. (1) The chemical substances identified generically as alkyl...

  17. Injectible bodily prosthetics employing methacrylic copolymer gels

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-02-27

    The present invention provides novel block copolymers as structural supplements for injectible bodily prosthetics employed in medical or cosmetic procedures. The invention also includes the use of such block copolymers as nucleus pulposus replacement materials for the treatment of degenerative disc disorders and spinal injuries. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol) methyl ether polymer.

  18. Single femtosecond pulse holography using polymethyl methacrylate.

    PubMed

    Li, Yan; Yamada, Kazuhiro; Ishizuka, Tomohiko; Watanabe, Wataru; Itoh, Kazuyoshi; Zhou, Zhongxiang

    2002-10-21

    Holographic gratings have been written on the surface and inside transparent polymethyl methacrylate (PMMA) with individual 130 fs laser pulses at 800 nm. A surface-relief grating is fabricated by ablation and the diffraction efficiency is measured to be about 20%. A volume grating inside PMMA is formed by the change in the refractive index induced by the two-beam interference fringes. Holographic data storage on the surface is realized when one beam carries information. The stored information can be nondestructively reconstructed when the fluence of the read beam is reduced below the threshold.

  19. Methacrylic resin having a high solar radiant energy absorbing property and process for producing the same

    SciTech Connect

    Abe, K.; Kamada, K.; Nakai, Y.

    1981-10-20

    A methacrylic resin having a high solar radiant energy absorbing property wherein an organic compound (A) containing cupric ion and a compound (B) having at least one p-o-h bond in a molecule are contained into the methacrylic resin selected from poly(Methyl methacrylate) or methacrylic polymers containing at least 50% by weight of a methyl methacrylate unit. A process for producing said methacrylic resin is also disclosed.

  20. Cell-laden microengineered gelatin methacrylate hydrogels

    PubMed Central

    Nichol, Jason W.; Koshy, Sandeep; Bae, Hojae; Hwang, Chang Mo; Yamanlar, Seda; Khademhosseini, Ali

    2010-01-01

    The cellular microenvironment plays an integral role in improving the function of microengineered tissues. Control of the microarchitecture in engineered tissues can be achieved through photopatterning of cell-laden hydrogels. However, despite high pattern fidelity of photopolymerizable hydrogels, many such materials are not cell-responsive and have limited biodegradability. Here we demonstrate gelatin methacrylate (GelMA) as an inexpensive, cell-responsive hydrogel platform for creating cell-laden microtissues and microfluidic devices. Cells readily bound to, proliferated, elongated and migrated both when seeded on micropatterned GelMA substrates as well as when encapsulated in microfabricated GelMA hydrogels. The hydration and mechanical properties of GelMA were demonstrated to be tunable for various applications through modification to the methacrylation degree and gel concentration. Pattern fidelity and resolution of GelMA was high and it could be patterned to create perfusable microfluidic channels. Furthermore, GelMA micropatterns could be used to create cellular micropatterns for in vitro cell studies or 3D microtissue fabrication. These data suggest that GelMA hydrogels could be useful for creating complex, cell-responsive microtissues, such as endothelialized microvasculature, or for other applications that requires cell-responsive microengineered hydrogels. PMID:20417964

  1. Cell-laden microengineered gelatin methacrylate hydrogels.

    PubMed

    Nichol, Jason W; Koshy, Sandeep T; Bae, Hojae; Hwang, Chang M; Yamanlar, Seda; Khademhosseini, Ali

    2010-07-01

    The cellular microenvironment plays an integral role in improving the function of microengineered tissues. Control of the microarchitecture in engineered tissues can be achieved through photopatterning of cell-laden hydrogels. However, despite high pattern fidelity of photopolymerizable hydrogels, many such materials are not cell-responsive and have limited biodegradability. Here, we demonstrate gelatin methacrylate (GelMA) as an inexpensive, cell-responsive hydrogel platform for creating cell-laden microtissues and microfluidic devices. Cells readily bound to, proliferated, elongated, and migrated both when seeded on micropatterned GelMA substrates as well as when encapsulated in microfabricated GelMA hydrogels. The hydration and mechanical properties of GelMA were demonstrated to be tunable for various applications through modification of the methacrylation degree and gel concentration. The pattern fidelity and resolution of GelMA were high and it could be patterned to create perfusable microfluidic channels. Furthermore, GelMA micropatterns could be used to create cellular micropatterns for in vitro cell studies or 3D microtissue fabrication. These data suggest that GelMA hydrogels could be useful for creating complex, cell-responsive microtissues, such as endothelialized microvasculature, or for other applications that require cell-responsive microengineered hydrogels.

  2. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  3. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  4. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  5. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  6. 40 CFR 721.10053 - Alkyl silane methacrylate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl silane methacrylate (generic... Specific Chemical Substances § 721.10053 Alkyl silane methacrylate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as alkyl...

  7. DEGRADATION OF POLY(METHYL METHACRYLATE) IN SOLUTION

    EPA Science Inventory

    The rate of degradation of poly(methyl methacrylate) (PMMA) to methyl methacrylate (MMA) was investigated in the liquid phase with toluene as the solvent. The degradation experiments were carried out in a tubular flow reactor at 1000 psig (6.8 MPa) and at four different temperat...

  8. Regioselective ester cleavage during the preparation of bisphosphonate methacrylate monomers

    PubMed Central

    Chougrani, Kamel; Niel, Gilles; Boutevin, Bernard

    2011-01-01

    Summary New functional monomers bearing a methacrylate, a bisphosphonate function and, for most, an internal carboxylate group, were prepared for incorporation into copolymers with adhesive or anticorrosive properties. Methanolysis of some trimethylsilyl bisphosphonate esters not only deprotects the desired bisphosphonate function but also regioselectively cleaves the alkyl ester function without affecting the methacrylate ester. PMID:21512600

  9. Improvement of holographic thermal stability in phenanthrenequinone-doped poly(methyl methacrylate-co-methacrylic acid) photopolymer

    NASA Astrophysics Data System (ADS)

    Yu, Dan; Liu, Hongpeng; Wang, Heng; Wang, Jian; Jiang, Yongyuan; Sun, Xiudong

    2011-08-01

    Experimental studies of holographic thermal stability in phenanthrenequinone (PQ)-doped poly(methyl methacrylate-co-methacrylic acid) [P(MMA-co-MAA)] photopolymers are presented. A possibility to improve the thermal stability of holograms is demonstrated by doping methacrylic acid (MAA) into the poly(methyl methacrylate) (PMMA) polymer matrix. MAA as a copolymerization monomer can form a more stable polymer matrix with methyl methacrylate (MMA) monomer and increase average molecular weight of photoproducts, which finally depress the diffusion of photoproduct. The optimized MAA concentration copolymerized into P(MMA-co-MAA) polymer matrix can bring nearly a month's lifetime of gratings, which is obviously an improvement over the usual PQ-PMMA material under thermal treatment.

  10. Preparation of ultrafine poly(methyl methacrylate-co-methacrylic acid) biodegradable nanoparticles loaded with ibuprofen.

    PubMed

    Saade, Hened; Diaz de León-Gómez, Ramón; Enríquez-Medrano, Francisco Javier; López, Raúl Guillermo

    2016-08-01

    Ibuprofen-loaded polymeric particles with around 9.2 nm in mean diameter, as determined by electron microscopy, dispersed in an aqueous media containing up to 12.8% solids were prepared by semicontinuous heterophase polymerization. The polymeric material is a (2/1 mol/mol) methyl methacrylate-co-methacrylic acid copolymer similar to Eudragit S100, deemed safe for human consumption and used in the manufacturing of drug-loaded pills as well as micro- and nanoparticles. The loading efficiency was 100%, attaining around 10-12% in drug content. Release studies showed that the drug is released from the nanoparticles at a slower rate than that in the case of free IB. Given their size as well as the pH values required for their dissolution, it is believed that this type of particles could be used as a basis for preparing nanosystems loaded with a variety of drugs.

  11. Preparation of ultrafine poly(methyl methacrylate-co-methacrylic acid) biodegradable nanoparticles loaded with ibuprofen.

    PubMed

    Saade, Hened; Diaz de León-Gómez, Ramón; Enríquez-Medrano, Francisco Javier; López, Raúl Guillermo

    2016-08-01

    Ibuprofen-loaded polymeric particles with around 9.2 nm in mean diameter, as determined by electron microscopy, dispersed in an aqueous media containing up to 12.8% solids were prepared by semicontinuous heterophase polymerization. The polymeric material is a (2/1 mol/mol) methyl methacrylate-co-methacrylic acid copolymer similar to Eudragit S100, deemed safe for human consumption and used in the manufacturing of drug-loaded pills as well as micro- and nanoparticles. The loading efficiency was 100%, attaining around 10-12% in drug content. Release studies showed that the drug is released from the nanoparticles at a slower rate than that in the case of free IB. Given their size as well as the pH values required for their dissolution, it is believed that this type of particles could be used as a basis for preparing nanosystems loaded with a variety of drugs. PMID:27126476

  12. Poly(ethyl methacrylate) and poly(2-ethoxyethyl methacrylate) based polymer gel electrolytes

    NASA Astrophysics Data System (ADS)

    Reiter, Jakub; Michálek, Jiří; Vondrák, Jiří; Chmelíková, Dana; Přádný, Martin; Mička, Zdeněk

    New poly(ethyl methacrylate) and poly(2-ethoxyethyl methacrylate) gel electrolytes containing immobilised lithium perchlorate solution in propylene carbonate were prepared by UV radical polymerisation. Materials exhibit high ionic conductivity up to 0.23 mS cm -1 and long-term stability of chemical and mechanical properties. Both materials keep their suitable conductivity above -20 °C. The effect of material composition, temperature, cross-linking agent and salt concentration on the electrochemical and mechanical properties were studied using impedance spectroscopy and cyclic voltammetry. The accessible electrochemical window of both polymer electrolytes was estimated from -2.1 to 1.5 V versus Cd/Cd 2+. Impedance measurements showed almost one-order increase of conductivity when ethylene dimethacrylate was used as a cross-linking agent in comparison with the polymer electrolyte without agent.

  13. Biocompatible Bacterial Cellulose-Poly(2-hydroxyethyl methacrylate) Nanocomposite Films

    PubMed Central

    Figueiredo, Andrea G. P. R.; Figueiredo, Ana R. P.; Alonso-Varona, Ana; Fernandes, Susana C. M.; Palomares, Teodoro; Rubio-Azpeitia, Eva; Barros-Timmons, Ana; Silvestre, Armando J. D.; Pascoal Neto, Carlos; Freire, Carmen S. R.

    2013-01-01

    A series of bacterial cellulose-poly(2-hydroxyethyl methacrylate) nanocomposite films was prepared by in situ radical polymerization of 2-hydroxyethyl methacrylate (HEMA), using variable amounts of poly(ethylene glycol) diacrylate (PEGDA) as cross-linker. Thin films were obtained, and their physical, chemical, thermal, and mechanical properties were evaluated. The films showed improved translucency compared to BC and enhanced thermal stability and mechanical performance when compared to poly(2-hydroxyethyl methacrylate) (PHEMA). Finally, BC/PHEMA nanocomposites proved to be nontoxic to human adipose-derived mesenchymal stem cells (ADSCs) and thus are pointed as potential dry dressings for biomedical applications. PMID:24093101

  14. Amphiphilic Zwitterionic Coatings for Marine Anti-Biofouling Applications

    NASA Astrophysics Data System (ADS)

    Walker, Edwin, Jr.; Pandiyarajan, C. K.; Efimenko, Kirill; Genzer, Jan

    Marine biofouling is a problem plaguing the surfaces of cargo ships, military ships and submarines. Previous approaches have relied primarily on the use of Cu-based coatings, which have deleterious effects on aquatic life. Recently, the vast majority of research efforts have focused on the use of polymer brushes synthesized by controlled radical polymerization to create either, the commonly used PEG/PEO materials, amphiphilic alternatives or promising zwitterionic-based moieties. Our approach is based on copolymerizing N, N -2-dimethylaminoethyl methacrylate (DMAEMA) and propargyl methacrylate (PgMA) in different molar ratios (typically, 1:1 and 3:1) using AIBN-based free radical initiator. The copolymers are then betainized with 1, 3- propane sultone to obtain zwitterionic macromolecules. We create substrate-anchored hydrogels by casting the copolymers as films onto polystyrene-based substrates and crosslink them using a photo-active reagent benzophenone. We investigate the cross-linking reaction with IR, the thickness and swelling as a function of ionic strength and electrolyte using spectroscopic ellipsometry and the wettability using water contact angle. We study the resistance of the coatings towards non-specific protein adsorption using fibrinogen and BSA.

  15. Final report of the safety assessment of methacrylic acid.

    PubMed

    2005-01-01

    Methacrylic Acid is an organic acid used at concentrations between 50 and 88 percent to pretreat the nail and maximize the adhesion between the nail and artificial nail extender. Methacrylic Acid is readily absorbed through mucous membranes of the lungs, the gastrointestinal tract, and the skin; and is distributed to all major tissues. Oral LD50 values for rats ranged from 277 to 2260 mg/kg; acute toxicity symptoms included severe gastric irritation, gasping, labored respiration, prostration and hematuria. In a short-term inhalation study, rats exposed to Methacrylic Acid at 1300 ppm showed nose and eye irritation and weight loss, while necropsy results and blood and urine tests were normal. Methacrylic Acid is an ocular toxicant in animals. Undiluted Methacrylic Acid is corrosive to the skin of rabbits and guinea pigs. Exposure as limited as 3 minutes can cause severe erythema and slight to moderate edema. Exposure from 15 minutes to 24 hours under occlusive patches can cause marked to severe discoloration, slight to severe subcutaneous hemorrhages, necrosis, ulcerations, severe erythema, edema and concave eschar. Methacrylic Acid was irritating and caused strong rubefaction and scab formation in a guinea pig maximization test at challenge concentrations from 10 to 100 percent. It was difficult to determine if the results were type IV hypersensitivity reactions or simple irritation. In three other studies, guinea pigs were not sensitized. Methacrylic Acid was not a reproductive/developmental toxicant in rats or mice. Methacrylic Acid was negative in Salmonella typhimurium mutagenicity tests using strains TA98, TA100, TA1535 and TA1537 both with and without metabolic activation, but was positive in a DNA-cell-binding assay. Case reports involving Methacrylic Acid often involve children. Effects from ingestion include drooling, gagging, and vomiting. Children exposed to Methacrylic Acid as a result of accidental spills caused first and second degree burns to the

  16. Polyelectrolyte brushes: a novel stable lubrication system in aqueous conditions.

    PubMed

    Kobayashi, Motoyasu; Terada, Masami; Takahara, Atsushi

    2012-01-01

    Surface-initiated controlled radical copolymerizations of 2-dimethylaminoethyl methacrylate (DMAEMA), 2-(methacryloyloxy)ethyl phosphorylcholine (MPC), 2-(methacryloyloxy)ethyltrimethylammonium chloride) (MTAC), and 3-sulfopropyl methacrylate potassium salt (SPMK) were carried out on a silicon wafer and glass ball to prepare polyelectrolyte brushes with excellent water wettability. The frictional coefficient of the polymer brushes was recorded on a ball-on-plate type tribometer by linear reciprocating motion of the brush specimen at a selected velocity of 1.5 x 10(-3) m s-1 under a normal load of 0.49 N applied to the stationary glass ball (d = 10 mm) at 298 K. The poly(DMAEMA-co-MPC) brush partially cross-linked by bis(2-iodoethoxy)ethane maintained a relatively low friction coefficient around 0.13 under humid air (RH > 75%) even after 200 friction cycles. The poly(SPMK) brush revealed an extremely low friction coefficient around 0.01 even after 450 friction cycles. We supposed that the abrasion of the brush was prevented owing to the good affinity of the poly(SPMK) brush for water forming a water lubrication layer, and electrostatic repulsive interactions among the brushes bearing sulfonic acid groups. Furthermore, the poly(SPMK-co-MTAC) brush with a chemically cross-linked structure showed a stable low friction coefficient in water even after 1400 friction cycles under a normal load of 139 MPa, indicating that the cross-linking structure improved the wear resistance of the brush layer. PMID:23285641

  17. Final report of the Cosmetic Ingredient Review Expert Panel safety assessment of polymethyl methacrylate (PMMA), methyl methacrylate crosspolymer, and methyl methacrylate/glycol dimethacrylate crosspolymer.

    PubMed

    Becker, Lillian C; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2011-05-01

    Polymethyl methacrylate (PMMA) and related cosmetic ingredients methyl methacrylate crosspolymer and methyl methacrylate/glycol dimethacrylate crosspolymer are polymers that function as film formers and viscosity-increasing agents in cosmetics. The Food and Drug Administration (FDA) determination of safety of PMMA use in several medical devices, which included human and animal safety data, was used as the basis of safety of PMMA and related polymers in cosmetics by the Cosmetic Ingredient Review (CIR) Expert Panel.  The PMMA used in cosmetics is substantially the same as in medical devices.  The Panel concluded that these ingredients are safe as cosmetic ingredients in the practices of use and concentrations as described in this safety assessment. PMID:21772027

  18. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation.

  19. Furfuryl methacrylate plasma polymers for biomedical applications.

    PubMed

    Shirazi, Hanieh Safizadeh; Rogers, Nicholas; Michelmore, Andrew; Whittle, Jason D

    2016-01-01

    Furfuryl methacrylate (FMA) is a promising precursor for producing polymers for biomedical and cell therapy applications. Herein, FMA plasma polymer coatings were prepared with different powers, deposition times, and flow rates. The plasma polymer coatings were characterized using atomic force microscopy (AFM), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The results from AFM and SEM show the early growth of the coatings and the existence of particle aggregates on the surfaces. XPS results indicated no measureable chemical differences between the deposited films produced under different power and flow rate conditions. ToF-SIMS analysis demonstrated differing amounts of C5H5O (81 m/z) and C10H9O2 (161 m/z) species in the coatings which are related to the furan ring structure. Through judicious choice of plasma polymerization parameters, the quantity of the particle aggregates was reduced, and the fabricated plasma polymer coatings were chemically uniform and smooth. Primary human fibroblasts were cultured on FMA plasma polymer surfaces to determine the effect of surface chemical composition and the presence of particle aggregates on cell culture. Particle aggregates were shown to inhibit fibroblast attachment and proliferation. PMID:27609095

  20. Complex microparticulate systems based on glycidyl methacrylate and xanthan.

    PubMed

    Lungan, Maria-Andreea; Popa, Marcel; Desbrieres, Jacques; Racovita, Stefania; Vasiliu, Silvia

    2014-04-15

    Porous microparticles based on glycidyl methacrylate, dimethacrylic monomers [ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate] and xanthan gum were synthesized by aqueous suspension polymerization method in the presence of toluene as diluent using two types of initiators: benzoyl peroxide and ammonium persulfate. The G microparticles based on glycidyl methacrylate and dimethacrylic monomers and X microparticles based on glycidyl methacrylate, xanthan and dimethacrylic monomers were characterized by various techniques including FT-IR spectroscopy, TG analysis, SEM analysis and DVS method. The specific surface areas were determined by DVS method, while the copolymer porosities and pore volume were obtained from the apparent and skeletal densities. The results have indicated that xanthan was included in the crosslinked matrix by means of covalent bonds. X microparticles have a porous structure with higher specific surface area (129-44 m(2)/g) and higher sorption capacities compared with G microparticles (69-31 m(2)/g). PMID:24607180

  1. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... modified alkyl methacrylate copolymer. 721.7200 Section 721.7200 Protection of Environment ENVIRONMENTAL... alkyl methacrylate copolymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  2. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... modified alkyl methacrylate copolymer. 721.7200 Section 721.7200 Protection of Environment ENVIRONMENTAL... alkyl methacrylate copolymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  3. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... modified alkyl methacrylate copolymer. 721.7200 Section 721.7200 Protection of Environment ENVIRONMENTAL... alkyl methacrylate copolymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  4. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... modified alkyl methacrylate copolymer. 721.7200 Section 721.7200 Protection of Environment ENVIRONMENTAL... alkyl methacrylate copolymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  5. 40 CFR 721.7200 - Perfluoroalkyl aromatic carbamate modified alkyl methacrylate copolymer.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... modified alkyl methacrylate copolymer. 721.7200 Section 721.7200 Protection of Environment ENVIRONMENTAL... alkyl methacrylate copolymer. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as perfluoroalkyl aromatic carbamate modified...

  6. DISPERSION POLYMERIZATION OF 2-HYDROXYETHYL METHACRYLATE IN SUPERCRITICAL CARBON DIOXIDE. (R826115)

    EPA Science Inventory

    Herein we report a successful dispersion polymerization of 2-hydroxyethyl methacrylate (HEMA) in a carbon dioxide continuous phase with a block copolymer consisting of polystyrene and poly(1,1-dihydroperfluorooctyl acrylate) as a stabilizer. Poly(2-hydroxyethyl methacrylate) was ...

  7. Structual Studies of Poly(Fluoroalkyl Methacrylate)s and Poly(Fluoroalkyl α-Fluoroacrylate)s

    NASA Astrophysics Data System (ADS)

    Koizumi, Shun; Ohmori, Akira; Shimizu, Tetuo; Iwami, Motohiro

    1992-10-01

    Poly(fluoroalkyl methacrylate)s and poly(fluoroalkyl α-fluoroacrylate)s with various fluoroalkyl groups were prepared. These polymers were characterized for tacticity by proton and fluorine nuclear magnetic resonance (1H and 19F NMR) and investigated by Electron Spectroscopy for Chemical Analysis (ESCA) to assign each signal. We found that tacticity of poly(fluoroalkyl α-fluoroacrylate)s were independent of the fluoroalkyl structure. The relationship between the structure of polymers and ESCA signals for all polymers was clarified. Also, we found an orientation effect of fluoroalkyl groups on the surface of the polymer films through the analysis of F1s ESCA signals.

  8. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic.../methyl methacrylate polymers. The vinylidene chloride/methyl acrylate/methyl methacrylate polymers...

  9. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  10. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  11. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hydroxypropyl methacrylate, reaction... Substances § 721.10375 Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate,...

  12. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  13. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Hydroxypropyl methacrylate, reaction... Substances § 721.10375 Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate,...

  14. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  15. 40 CFR 721.10375 - Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide, copolymer...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Hydroxypropyl methacrylate, reaction... Substances § 721.10375 Hydroxypropyl methacrylate, reaction products with propylene oxide and ethylene oxide... reporting. (1) The chemical substance identified generically as hydroxypropyl methacrylate,...

  16. 21 CFR 73.3127 - Vinyl alcohol/methyl methacrylate-dye reaction products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Vinyl alcohol/methyl methacrylate-dye reaction... Vinyl alcohol/methyl methacrylate-dye reaction products. (a) Identity. The color additives are formed by... methacrylate-dye reaction product listed under this section into commerce shall submit to the Food and...

  17. Crosslinked superhydrophobic films fabricated by simply casting poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-poly(perfluorohexylethyl methacrylate) solution

    NASA Astrophysics Data System (ADS)

    Wen, Xiufang; Ye, Chao; Cai, Zhiqi; Xu, Shouping; Pi, Pihui; Cheng, Jiang; Zhang, Lijuan; Qian, Yu

    2015-06-01

    This study focuses on the preparation of superhydrophobic films by crosslinkable polymer material-Poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-Poly(perfluorohexylethyl methacrylate) (P (MMA-BA-HEMA)-b-PFMA) with a simple one-step casting process. Nanoscale micelle particles with core-shell structure was obtained by dissolving the polymer and curing agent in the mixture of acetone and 1H, 1H, 5H octafluoropentyl-1,1,2,2 tetrafluoroethyl ether (FHT). Superhydrophobic films were fabricated by casting the micelle solution on the glass slides. By controlling the polymer concentration and acetone/FHT volume ratio, superhydrophobic polymer film with water contact angle of 153.2 ± 2.1° and sliding angle of 4° was obtained. By introducing a curing agent into the micelle solution, mechanical properties of the films can be improved. The adhension grade and hardness of the crosslinked superhydrophobic films reached 2 grade and 3H, respectively. The hydrophobicity is attributed to the synergistic effect of micro-submicro-nano-meter scale roughness by nanoscale micelle particles and low surface energy of fluoropolymer. This procedure makes it possible for widespread applications of superhydrophobic film due to its simplicity and practicability.

  18. Allergic contact dermatitis to methacrylates in ECG electrode dots.

    PubMed

    Lyons, Georgina; Nixon, Rosemary

    2013-02-01

    Acrylates are used widely in acrylic nails, dental restorative materials, paint, varnish, printing ink, adhesives, glue, orthopaedic prostheses, bone cement and diathermy pads. This is the first case of allergic contact dermatitis to methacrylates in electrocardiogram electrode dots reported in the literature.

  19. Synthesis of acrylates and methacrylates from coal-derived syngas

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Jang, B.W.L.

    1995-12-31

    Acrylates and methacrylates are among the most widely used chemical intermediates in the world. One of the key chemicals of this type is methyl methacrylate. Of the 4 billion pounds produced each year, roughly 85% is made using the acetone-cyanohydrin process, which requires handling of large quantities of hydrogen cyanide and produces ammonium sulfate wastes that pose an environmental disposal challenge. The U.S. Department of Energy and Eastman Chemical Company are sharing the cost of research to develop an alternative process for the synthesis of methyl methacrylate from syngas. Research Triangle Institute is focusing on the synthesis and testing of active catalysts for the condensation reactions, and Bechtel is analyzing the costs to determine the competitiveness of several process alternatives. Results thus far show that the catalysts for the condensation of formaldehyde and the propionate are key to selectively producing the desired product, methacrylic acid, with a high yield. These condensation catalysts have both acid and base functions and the strength and distribution of these acid-base sites controls the product selectivity and yield.

  20. 21 CFR 172.775 - Methacrylic acid-divinylbenzene copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Methacrylic acid-divinylbenzene copolymer. 172.775 Section 172.775 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD...

  1. 21 CFR 177.1830 - Styrene-methyl methacrylate copolymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Styrene-methyl methacrylate copolymers. 177.1830 Section 177.1830 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as Basic Components of Single and...

  2. Release of Water Soluble Drugs from Dynamically Swelling POLY(2-HYDROXYETHYL Methacrylate - CO - Methacrylic Acid) Hydrogels.

    NASA Astrophysics Data System (ADS)

    Kou, Jim Hwai-Cher

    In this study, ionizable copolymers of HEMA and methacrylic acid (MA) are investigated for their potential use in developing pH dependent oral delivery systems. Because of the MA units, these gels swell extensively at high pH. Since solute diffusion in the hydrophilic polymers depends highly on the water content of the matrix, it is anticipated that the release rate will be modulated by this pH induced swelling. From a practical point of view, the advantage of the present system is that one can minimize drug loss in the stomach and achieve a programmed release in intestine. This approach is expected to improve delivery of acid labile drugs or drugs that cause severe gastrointestinal side effects. This work mainly focuses on the basic understanding of the mechanism involved in drug release from the poly(HEMA -co- MA) gels, especially under dynamic swelling conditions. Equilibrium swelling is first characterized since water content is the major determinant of transport properties in these gels. Phenylpropanolamine (PPA) is chosen as the model drug for the release study and its diffusion characteristics in the gel matrix determined. The data obtained show that the PPA diffusivity follows the free volume theory of Yasuda, which explains the accelerating effect of swelling on drug release. A mathematical model based on a diffusion mechanism has been developed to describe PPA release from the swelling gels. Based on this model, several significant conclusions can be drawn. First, the release rate can be modulated by the aspect ratio of the cylindrical geometry, and this has a practical implication in dosage form design. Second, the release rate can be lowered quite considerably if the dimensional increase due to swelling is significant. Consequently, it is the balance between the drug diffusivity increase and the gel dimensional growth that determines the release rate from the swelling matrix. Third, quasi-steady release kinetics, which are characteristic of swelling

  3. Effect of reaction parameters on synthesis of citronellyl methacrylate by lipase-catalyzed transesterification.

    PubMed

    Athawale, Vilas; Manjrekar, Narendra; Athawale, Manoj

    2003-01-01

    The methacrylate ester of citronellol was synthesized using various lipases as catalyst. The effect of different reaction parameters such as amount of lipase, solvent, temperature, and acylating agent on the conversion of citronellol to citronellyl methacrylate was studied. Methyl methacrylate, vinyl methacrylate, and 2,3-butanedione mono-oxime methacrylate were used as acylating agents. Porcine pancreatic lipase (PPL), Candida rugosa lipase (CRL), and Pseudomonas cepacia lipase (Amano-PS) were used as biocatalysts. Diisopropyl ether (DIPE) was found to be the most suitable solvent. The stereoselectivity of CRL in transesterification of (+/-)-citronellol was tested for the optimized reaction parameters.

  4. Polymerization contraction and conversion of light-curing BisGMA-based methacrylate resins.

    PubMed

    Venhoven, B A; de Gee, A J; Davidson, C L

    1993-09-01

    The aim of this study was to investigate the polymerization contraction and the conversion of light-curing methacrylate resins based on bisphenol-A bis(2-hydroxypropyl)methacrylate (BisGMA) diluted with triethylene glycol dimethyacrylate (TEGDMA), methyl methacrylate (MMA), hydroxypropyl methacrylate (HPMA) or (+/-)-2-ethylhexyl methacrylate (EHMA). The contraction measurements were carried out with a linometer, a simple device to determine true linear polymerization contraction of liquid monomers at ambient temperature. The contraction increased with the amount of diluting monomer. The estimated conversion of the BisGMA-TEGDMA, calculated using the contraction, is consistent with literature values. The BisGMA-HPMA mixtures showed high conversions at moderate contraction.

  5. Investigation of Methacrylic Acid at High Pressure Using Neutron Diffraction.

    PubMed

    Marshall, William G; Urquhart, Andrew J; Oswald, Iain D H

    2015-09-10

    This article shows that pressure can be a low-intensity route to the synthesis of polymethacrylic acid. The exploration of perdeuterated methacrylic acid at high pressure using neutron diffraction reveals that methacrylic acid exhibits two polymorphic phase transformations at relatively low pressures. The first is observed at 0.39 GPa, where both phases were observed simultaneously and confirm our previous observations. This transition is followed by a second transition at 1.2 GPa to a new polymorph that is characterized for the first time. On increasing pressure, the diffraction pattern of phase III deteriorates significantly. On decompression phase III persists to 0.54 GPa before transformation to the ambient pressure phase. There is significant loss of signal after decompression, signifying that there has been a loss of material through polymerization. The orientation of the molecules in phase III provides insight into the possible polymerization reaction. PMID:26289930

  6. SYNTHESIS OF METHACRYLATES FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Jang, B.W.L.; Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.

    1999-12-01

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel have developed a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the US Department of Energy/Fossil Energy Technology Center (DOE/FETC). This project has resulted in five US patents (four already published and one pending publication). It has served as the basis for the technical and economic assessment of the production of this high-volume intermediate from coal-derived synthesis gas. The three-step process consists of the synthesis of a propionate from ethylene carbonylation using coal-derived CO, condensation of the propionate with formaldehyde to form methacrylic acid (MAA); and esterification of MAA with methanol to yield MMA. The first two steps, propionate synthesis and condensation catalysis, are the key technical challenges and the focus of the research presented here.

  7. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi; Samuel S. Tam

    1999-04-21

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (January-March/99), in-situ formaldehyde generation and condensation with methyl propionate were tested over various catalysts and reaction conditions. The patent application is in preparation and the results are retained for future reports.

  8. Physical properties of agave cellulose graft polymethyl methacrylate

    SciTech Connect

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-27

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm{sup −1} which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  9. Preparation and characterization of methacrylate hydrogels for zeta potential control

    NASA Technical Reports Server (NTRS)

    Gregonis, D. E.; Ma, S. M.; Vanwagenen, R.; Andrade, J. D.

    1976-01-01

    A technique based on the measurement of streaming potentials has been developed to evaluate the effects of hydrophilic coatings on electroosmotic flow. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of glass capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming potential measurements is discussed. Various silane adhesion promoters exhibited only a slight decrease in streaming potential. A coating utilizing a glycidoxy silane base upon which methylcellulose is applied affords a six-fold decrease over uncoated tubes. Hydrophilic methacrylate gels show similar streaming potential behavior, independent of the water content of the gel. By introduction of positive or negative groups into the hydrophilic methacrylate gels, a range of streaming potential values are obtained having absolute positive or negative signs.

  10. Physical properties of agave cellulose graft polymethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan

    2013-11-01

    The grafting polymerization of methyl methacrylate and Agave cellulose was prepared and their structural analysis and morphology were investigated. The grafting reaction was carried out in an aqueous medium using ceric ammonium nitrate as an initiator. The structural analysis of the graft copolymers was carried out by Fourier transform infrared and X-ray diffraction. The graft copolymers were also characterized by field emission scanning electron microscopy (FESEM). An additional peak at 1732 cm-1 which was attributed to the C=O of ester stretching vibration of poly(methyl methacrylate), appeared in the spectrum of grafted Agave cellulose. A slight decrease of crystallinity index upon grafting was found from 0.74 to 0.68 for cellulose and grafted Agave cellulose, respectively. Another evidence of grafting showed in the FESEM observation, where the surface of the grafted cellulose was found to be roughed than the raw one.

  11. Jumplike deformation of γ-irradiated polymethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Peschanskaya, N. N.; Smolyanskiĭ, A. S.; Shvedov, A. S.

    2009-06-01

    Nonuniformity of the microdeformation rate and the parameters of microdeformation jumps were studied in the creep regime for a polymethyl methacrylate irradiated by various dozes of the Co-60 γ radiation. The creep rate during compression of the polymethyl methacrylate was measured by an interferogram on 300-nm deformation increments. It is shown that the periods L of rate oscillations (jumps of deformation) on three scale levels are dependent on the irradiation doze and are also changed after prolonged exposure of samples in air. In the doze range 0 to 330 kGy, both a decrease and an increase in L are observed, which corresponds to the unstable kinetics of radiation chemical processes. The deformation jumps permit estimates of the radiation effect on various structural levels. It is concluded that the effect of radiation on coarser microstructural formations is the largest.

  12. Synthesis and characterization of magnetic poly(glycidyl methacrylate) microspheres

    NASA Astrophysics Data System (ADS)

    Horák, Daniel; Petrovský, Eduard; Kapička, Aleš; Frederichs, Theodor

    2007-04-01

    Magnetic nanoparticles encapsulated in poly(glycidyl methacrylate) microspheres were prepared and their detailed structural and magnetic characteristics given. Iron oxide nanoparticles were obtained by chemical coprecipitation of Fe(II) and Fe(III) salts and stabilized with dextran, (carboxymethyl)dextran or tetramethylammonium hydroxide. The microspheres were prepared by emulsion or dispersion polymerization of glycidyl methacrylate in the presence of ferrofluid. The microspheres were uniform both in shape and usually also in size; their size distribution was narrow. All the magnetic parameters confirm superparamagnetic nature of the microspheres. Blocking temperature was not observed, suggesting the absence of magnetic interactions at low temperatures. This is most probably caused by complete encapsulation and the absence of agglomeration. Such microspheres can be used in biomedical applications.

  13. Preparation and recovery of methacrylic acid and its esters

    SciTech Connect

    Frank, P.J.; Hite, J.R.

    1986-07-15

    This patent describes a process for the vapor phase catalytic oxydehydrogenation of isobutyric acid or its esters to form methacrylic acid or its esters wherein the gaseous product is condensed and purified. The improvement described here consists of adding to the gaseous product at or about the point of its condensation from 1 to 6000 ppm of a surfactant material selected from the group consisting of an anionic a cationic and non-ionic surfactant.

  14. Catalytic esterification of methacrylic acid with methyl alcohol

    SciTech Connect

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

    1987-08-10

    The authors contend that virtually all methods for the production of methacrylic acid esters suffer from the drawbacks of low conversion, dependence on costly catalysts, low feed rates, and the need to use inhibitors in the process. To eliminate these drawbacks, they propose and test a new catalyst, sulfopolyphenyl ketone, which contains an extensive conjugated bond system together with ionic hydroxide groups. The catalytic esterification rate and yield is given for this catalyst and chromatography is performed for the resulting esters.

  15. Methacrylate monolith chromatography as a tool for waterborne virus removal.

    PubMed

    Rački, N; Kramberger, P; Steyer, A; Gašperšič, J; Štrancar, A; Ravnikar, M; Gutierrez-Aguirre, I

    2015-02-13

    Enteric viruses are commonly present in environmental waters and represent the major cause of waterborne infections and outbreaks. Since traditional wastewater treatments fail to remove enteric viruses in the water purification process, they are released daily into environmental waters. Monolithic supports have enabled chromatography to enter the field of virology. They have been successfully used in virus purification and concentration. In this work quaternary amine (QA) methacrylate monoliths were exploited to remove enteric viruses from wastewater treatment plant effluent. Expectedly, chromatographic processing of such a complex medium was troublesome, even for monoliths, characterized by extremely large pore dimensions. This problem was solved by introducing a pre-step chromatography using hydroxyl (OH) methacrylate monoliths. This way, molecules, that would hinder virus binding to the anion-exchanger monolith, were removed. As a result, the OH pre-column reduced backpressure increase on the subsequent anion-exchanger column, and increased both QA column binding capacity and life time. Wastewater effluent samples were successfully purified from five waterborne enteric viruses (rotavirus, norovirus genogroup I and II, astrovirus, sapovirus), below the detection limit of RT-qPCR. The breakthrough of the rotavirus binding capacity was not reached for concentrations that significantly exceeded those expected in effluent waters. The obtained results confirm that methacrylate monoliths can be a valuable tool for simultaneous removal of different waterborne viruses from contaminated water sources.

  16. Magnetic poly(glycidyl methacrylate) microspheres for protein capture.

    PubMed

    Koubková, Jana; Müller, Petr; Hlídková, Helena; Plichta, Zdeněk; Proks, Vladimír; Vojtěšek, Bořivoj; Horák, Daniel

    2014-09-25

    The efficient isolation and concentration of protein antigens from complex biological samples is a critical step in several analytical methods, such as mass spectrometry, flow cytometry and immunochemistry. These techniques take advantage of magnetic microspheres as immunosorbents. The focus of this study was on the development of new superparamagnetic polymer microspheres for the specific isolation of the tumor suppressor protein p53. Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres measuring approximately 5 μm and containing carboxyl groups were prepared by multistep swelling polymerization of glycidyl methacrylate (GMA), 2-[(methoxycarbonyl)methoxy]ethyl methacrylate (MCMEMA) and ethylene dimethylacrylate (EDMA) as a crosslinker in the presence of cyclohexyl acetate as a porogen. To render the microspheres magnetic, iron oxide was precipitated within their pores; the Fe content in the particles received ∼18 wt%. Nonspecific interactions between the magnetic particles and biological media were minimized by coating the microspheres with poly(ethylene glycol) (PEG) terminated by carboxyl groups. The carboxyl groups of the magnetic PGMA microspheres were conjugated with primary amino groups of mouse monoclonal DO-1 antibody using conventional carbodiimide chemistry. The efficiency of protein p53 capture and the degree of nonspecific adsorption on neat and PEG-coated magnetic microspheres were determined by western blot analysis.

  17. Different in vitro and in vivo behaviors between Poly(carboxybetaine methacrylate) and poly(sulfobetaine methacrylate).

    PubMed

    Lin, Weifeng; Ma, Guanglong; Wu, Jiang; Chen, Shengfu

    2016-10-01

    Poly(sulfobetaine methacrylate) (pSBMA) and poly(carboxybetaine methacrylate) (pCBMA) are two well-known zwitterionic polymers known for their excellent antifouling properties. In this work, these two zwitterionic polymers were compared both in vitro and in vivo. Both of them exhibited excellent antifouling properties and low macrophage uptake although there were negligible differences in resistance to nonspecific protein adsorption of their hydrogels and cell internalization of their star polymers. However, it is found that the β- Cyclodextrin-CBMA (CD-CBMA) showed a circulation time one order of magnitude longer than CD-SBMA, which implied that small differences in vitro may lead to a dramatic difference in vivo. This work demonstrated that pCBMA showed greater potential than pSBMA in biomedical applications.

  18. Different in vitro and in vivo behaviors between Poly(carboxybetaine methacrylate) and poly(sulfobetaine methacrylate).

    PubMed

    Lin, Weifeng; Ma, Guanglong; Wu, Jiang; Chen, Shengfu

    2016-10-01

    Poly(sulfobetaine methacrylate) (pSBMA) and poly(carboxybetaine methacrylate) (pCBMA) are two well-known zwitterionic polymers known for their excellent antifouling properties. In this work, these two zwitterionic polymers were compared both in vitro and in vivo. Both of them exhibited excellent antifouling properties and low macrophage uptake although there were negligible differences in resistance to nonspecific protein adsorption of their hydrogels and cell internalization of their star polymers. However, it is found that the β- Cyclodextrin-CBMA (CD-CBMA) showed a circulation time one order of magnitude longer than CD-SBMA, which implied that small differences in vitro may lead to a dramatic difference in vivo. This work demonstrated that pCBMA showed greater potential than pSBMA in biomedical applications. PMID:27459415

  19. Development of thermosensitive poly(n-isopropylacrylamide-co-((2-dimethylamino) ethyl methacrylate))-based nanoparticles for controlled drug release

    NASA Astrophysics Data System (ADS)

    Peng, Cheng-Liang; Tsai, Han-Min; Yang, Shu-Jyuan; Luo, Tsai-Yueh; Lin, Chia-Fu; Lin, Wuu-Jyh; Shieh, Ming-Jium

    2011-07-01

    Thermosensitive nanoparticles based on poly(N-isopropylacrylamide-co-((2-dimethylamino)ethylmethacrylate)) (poly(NIPA-co-DMAEMA)) copolymers were successfully fabricated by free radical polymerization. The lower critical solution temperature (LCST) of the synthesized nanoparticles was 41 °C and a temperature above which would cause the nanoparticles to undergo a volume phase transition from 140 to 100 nm, which could result in the expulsion of encapsulated drugs. Therefore, we used the poly(NIPA-co-DMAEMA) nanoparticles as a carrier for the controlled release of a hydrophobic anticancer agent, 7-ethyl-10-hydroxy-camptothecin (SN-38). The encapsulation efficiency and loading content of SN-38-loaded nanoparticles at an SN-38/poly(NIPA-co-DMAEMA) ratio of 1/10 (D/P = 1/10) were about 80% and 6.293%, respectively. Moreover, the release profile of SN-38-loaded nanoparticles revealed that the release rate at 42 °C (above LCST) was higher than that at 37 °C (below LCST), which demonstrated that the release of SN-38 could be controlled by increasing the temperature. The cytotoxicity of the SN-38-loaded poly(NIPA-co-DMAEMA) nanoparticles was investigated in human colon cancer cells (HT-29) to compare with the treatment of an anticancer drug, Irinotecan® (CPT-11). The antitumor efficacy evaluated in a C26 murine colon tumor model showed that the SN-38-loaded nanoparticles in combination with hyperthermia therapy efficiently suppressed tumor growth. The results indicate that these thermo-responsive nanoparticles are potential carriers for controlled drug delivery.

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

    SciTech Connect

    Oberly, R.; Tansy, M.F.

    1985-01-01

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

  1. Jumpwise deformation of polymethyl methacrylate in the microplasticity region

    NASA Astrophysics Data System (ADS)

    Shpeizman, V. V.; Yakushev, P. N.; Mukhina, Zh. V.; Kuznetsov, E. V.; Smolyanskii, A. S.

    2013-05-01

    The deformation rate with a step of 325 nm has been measured under uniaxial compression at the initial stage of creep and shape recovery of a polymethyl methacrylate (PMMA) sample after unloading. The effect of low γ-ray doses and magnetic fields on the deformation has been studied. It has been shown that a weak pre-exposure of the PMMA sample structure to radiation and magnetic fields can cause a slight hardening in the microplasticity region. The deformation jump sizes have been determined on micro- and nanoscales. The effect of irradiation and magnetic fields manifests itself as redistributed contributions of various jumps to the deformation.

  2. Mechanism of the photoinduced refractive index increase in polymethyl methacrylate.

    PubMed

    Bowden, M J; Chandross, E A; Kaminow, I P

    1974-01-01

    Polymethyl methacrylate prepared under special circumstances exhibits a substantial increase in refractive index after irradiation with uv light. The essential step in the preparation is peroxidation of the monomer prior to polymerization. This increase in refractive index results from a photoinduced polymerization of unreacted monomer (1-2%) within the film which produces an increase in density (and hence refractive index) in the irradiated region. It is believed that peroxides, both polymeric and monomeric, act as photoinitiators. Sensitivity depends on the concentration of photoinitiator, but the absolute value of Deltan depends on the amount of unreacte monomer.

  3. The immobilization of enzymes onto poly(ethylene)—g.co—methacrylic acid, [poly(ethylene)—g.co—hydroxyethyl methacrylate]—g.co—methacrylic acid and [poly(ethylene)—g.co—methacrylic acid]—g.co—hydroxyethyl methacrylate

    NASA Astrophysics Data System (ADS)

    Da Silva, M. Alves; Gil, M. H.; Guiomar, J.; Lapa, E.; Machado, E.; Moreira, M.; Guthrie, J. T.; Kotov, S.

    A series of graft copolymers has been prepared based on the poly(ethylene) backbone. These carry functional groups which are effective in coupling and provide a level of hydrophilicity which is thought to be consistent with generating a suitable micro-environment for enzyme immobilization and subsequent enhanced biocatalyst stability. Four enzymes have been immobilized. These are papain, trypsin, glucose oxidase and α-chymotrypsin. The parent copolymers were assembled via radiation-induced grafting. Secondary grafting was achieved in two ways. The first involved grafting methacrylic acid onto poly(ethylene)—g.co—hydroxyethyl methacrylate, while the second involved grafting hydroxyethyl methacrylate onto poly(ethylene)—g.co—methacrylic acid. The results suggest that a high degree of specificity arises in the systems examined with regard to the enzymes, the type of copolymers and the coupling procedures. Generally, relatively large amounts of enzyme become covalently attached to the copolymers, though the overall level of activity is low. In this work it has been observed that the most satisfactory results were obtained when the partly hydrolyzed poly(ethylene)—g.co—hydroxyethyl methacrylate was used in the immobilization of the biocatalysts.

  4. Preparation of novel poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted core-shell magnetic chitosan microspheres and immobilization of lactase.

    PubMed

    Zhao, Wei; Yang, Rui-Jin; Qian, Ting-Ting; Hua, Xiao; Zhang, Wen-Bin; Katiyo, Wendy

    2013-06-06

    Poly(hydroxyethyl methacrylate-co-glycidyl methacrylate)-grafted magnetic chitosan microspheres (HG-MCM) were prepared using reversed-phase suspension polymerization method. The HG-MCM presented a core-shell structure and regular spherical shape with poly(hydroxyethyl methacrylate-co-glycidyl methacrylate) grafted onto the chitosan layer coating the Fe3O4 cores. The average diameter of the magnetic microspheres was 10.67 μm, within a narrow size distribution of 6.6-17.4 μm. The saturation magnetization and retentivity of the magnetic microspheres were 7.0033 emu/g and 0.6273 emu/g, respectively. The application of HG-MCM in immobilization of lactase showed that the immobilized enzyme presented higher storage, pH and thermal stability compared to the free enzyme. This indicates that HG-MCM have potential applications in bio-macromolecule immobilization.

  5. Silane to enhance the bond between polymethyl methacrylate and titanium.

    PubMed

    May, K B; Fox, J; Razzoog, M E; Lang, B R

    1995-05-01

    The machined surface of wrought titanium frameworks used in implant-supported, fixed prostheses does not bond well with acrylic resin. Surface pretreatment has been suggested to enhance the retention of polymethyl methacrylate to machined titanium surfaces. This study evaluated a new bonding material (Rocatec) to determine its effect on the bond strength between titanium and polymethyl methacrylate. Twenty rod-shaped specimens of grade 2 titanium (7.6 x 0.3 cm in diameter) were divided into two groups of 10 samples. Group A received no pretreatment and group B was pretreated with 110 microns alumina air abrasive and the Rocatec material. Heat-cured denture base resin was processed around each titanium sample in a cylindrical shape approximately 0.9 x 1.5 cm. A Shell-Nielsen shear test was performed with a universal testing machine at a crosshead speed of 0.5 mm/minute to determine the bond strength in megapascals (MPa). Group B specimens (23.8 +/- 1.78 MPa) had a shear strength 68% greater than group A (16.1 +/- 1.61 MPa) (p 0.0001). The results of this study indicated that surface pretreatment of grade 2 titanium with 110 microns alumina air abrasive plus Rocatec bonding material significantly enhances the shear bond strength to PMMA.

  6. Synthesis of Methyl Methacrylate from Coal-Derived Syngas

    SciTech Connect

    Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Makarand R. Gogate; Richard D. Colberg; Samuel S. Tam

    1998-04-17

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last month, RTI has finalized the design of a fixed-bed microreactor system for DME partial oxidation reactions. RTI incorporated some design changes to the feed blending system, so as to be able to blend varying proportions of DME and oxygen. RTI has also examined the flammability limits of DME-air mixtures. Since the lower flammability limit of DME in air is 3.6 volume percent, RTI will use a nominal feed composition of 1.6 percent in air, which is less than half the lower explosion limit for DME-air mixtures. This nominal feed composition is thus considered operationally safe, for DME partial oxidation reactions. RTI is also currently developing an analytical system for DME partial oxidation reaction system.

  7. Novel syngas-based process for methyl methacrylate

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Choi, G.N.; Tam, S.S.; Tischer, R.E.; Srivastava, R.D.

    1996-12-31

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel are developing a novel process for synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Pittsburgh Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the research on propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees}C and 180 atm). Bechtel has performed an extensive cost analysis, which shows that Eastman`s propionate synthesis process is competitive with other technologies to produce the anhydride. In the second step, RTI and Eastman have developed active and stable V-SI-P and Ta metal oxide catalysts for condensation reactions of propionates with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst activity. Current research focuses on enhancing the condensation reaction yields, acid-base properties, in situ condensation in a high- temperature, high-pressure (HTHP) slurry reactor, and alternate formaldehyde feedstocks. Based on Eastman and RTI laboratory reactor operating data, a cost estimate is also being developed for the integrated process.

  8. Superhydrophobic terpolymer nanofibers containing perfluoroethyl alkyl methacrylate by electrospinning

    NASA Astrophysics Data System (ADS)

    Cengiz, Ugur; Avci, Merih Z.; Erbil, H. Yildirim; Sarac, A. Sezai

    2012-05-01

    A new statistical terpolymer containing perfluoroethyl alkyl methacrylate (Zonyl-TM), methyl methacrylate and butyl acrylate, poly(Zonyl-TM-ran-MMA-ran-BA) was synthesized in supercritical carbon dioxide at 200 bar and 80 °C using AIBN as an initiator by heterogeneous free radical copolymerization. Nanofibers of this terpolymer were produced by electrospinning from its DMF solution. The structural and thermal properties of terpolymers and electrospun poly(Zonyl-TM-MMA-BA) nanofibers were analyzed using Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy and differential scanning calorimetry. Nanofiber morphology was investigated by scanning electron microscopy. Electrospun nanofiber layer was found to be superhydrophobic with a water contact angle of 172 ± 1° and highly oleophobic with hexadecane, glycerol and ethylene glycol contact angles of 70 ± 1°, 167 ± 1° and 163 ± 1° respectively. The change of the contact angle results on the electrospun fiber layer and flat terpolymer surfaces by varying feed monomer composition were compared and discussed in the text.

  9. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  10. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  11. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  12. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  13. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  14. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  15. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  16. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Butyl acrylate, polymer with... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  17. 21 CFR 177.2000 - Vinylidene chloride/methyl acrylate/methyl methacrylate polymers.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... methacrylate polymers. 177.2000 Section 177.2000 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF...: POLYMERS Substances for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.2000 Vinylidene chloride/methyl acrylate/methyl methacrylate polymers. The vinylidene chloride/methyl...

  18. 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.

  19. Investigation of infrared calibration methods for application to the study of methyl methacrylate polymerization.

    PubMed

    Kaczmarczyk, B; Morejko-Buz, B; Stolarzewicz, A

    2001-08-01

    Infrared spectroscopy has been used to monitor the polymerization of methyl methacrylate. Concentrations of methyl methacrylate in the reaction mixture were determined by use of three calibration methods. Classical quantitative analysis was used to measure the height of the stretching vibration bands of the vinyl group at 1639 cm(-1). A calibration procedure using the considerably higher intensity of the C = O stretching vibration band of the carbonyl ester group at 1725 cm(-1) seemed useful only for high concentrations of methyl methacrylate, i.e. at the beginning of reaction, because this band overlaps that of poly(methyl methacrylate). Use of second-derivative spectra and measuring their values at 1725 cm(-1) enabled estimation of ten times lower concentrations of methyl methacrylate the calibration using the band from the vinyl group. PMID:11569872

  20. Viability of hydroxyethyl methacrylate-methyl methacrylate-microencapsulated PC12 cells after omental pouch implantation within agarose gels.

    PubMed

    Fleming, A J; Sefton, M V

    2003-10-01

    Hydroxyethyl methacrylate-methyl methacrylate (HEMA-MMA, 75 mol% HEMA). Microcapsules containing viable PC12 cells (as an allogeneic transplant model) were implanted into omental pouches in Wistar rats. Two different capsule preparations were tested, based on differences in polymer solutions during extrusion: 10% HEMA-MMA in TEG, and 9% HEMA-MMA in TEG with 30% poly(vinyl pyrrolidone) (PVP). The omental pouch proved to be an ideal transplant site in terms of implantation, recovery, and blood vessel proximity (nutrient supply). To minimize the fibrous overgrowth and damaged capsules previously seen on implantation of individual capsules, agarose gels were used to embed the capsules before implantation. Cells proliferated within the microcapsule-agarose device during the first 7 days of implantation, but overall cell viability declined over the 3-week period, when compared with similar capsules maintained in vitro. Nonetheless, approximately 50% of the initial encapsulated cells were still viable after 3 weeks in vivo. This approach to HEMA-MMA microcapsule implantation improved cell viability and capsule integrity after 3 weeks in vivo, compared with capsules implanted without agarose.

  1. Acrylic resins: methacrylate polymers. 1964-April, 1981 (citations from the NTIS data base). Report for 1964-April 1981

    SciTech Connect

    Not Available

    1981-05-01

    Polymethyl methacrylate, polymethacrylic acid, and other methacrylate and methacrylic polymers, copolymers, and resins are covered in this bibliography. The citations include references concerning physical and chemical properties, synthesis, polymerization, and processing. (This updated bibliography contains 278 citations, 40 of which are new entries to the previous edition.)

  2. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG.

    1999-01-20

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(Oct.-Dec./98), we have investigated the condensation between methyl propionate and formaldehyde (MP/HCHO=4.5/1) at various reaction temperatures(280-360EC) over 5%, 10%, and 20% Nb O /SiO catalysts. The conversion of HCHO increases with reaction 2 5 2 temperature and niobium loading. MMA+MAA selectivity goes through a maximum with the temperature over both 10% and 20% Nb O /SiO . The selectivities to MMA+MAA are 67.2%, 2 5 2 72.3%and 58.1% at 320EC over 5%, 10%, 20% Nb O /SiO , respectively. However, the 2 5 2 conversion of formaldehyde decreases rapidly with time on stream. The results suggest that silica supported niobium catalysts are active and selective for condensation of MP with HCHO, but deactivation needs to be minimized for the consideration of commercial application. We have preliminarily investigated the partial oxidation of dimethyl ether(DME) over 5% Nb O /SiO catalyst. Reactant gas mixture of 0.1% DME, 0.1% O and balance nitrogen is 2 5 2 2 studied with temperature ranging from 200C to 500C. The conversion of DME first increases with temperature reaching an maximum at 400C then decreases. The selectivity to HCHO also increases with reaction temperature first. But the selectivity to HCHO decreases at temperature above 350C accompanied by

  3. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG

    1999-01-20

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(Oct.-Dec./98), we have investigated the condensation between methyl propionate and formaldehyde (MP/HCHO=4.5/1) at various reaction temperatures(280-360EC) over 5%, 10%, and 20% Nb O /SiO catalysts. The conversion of HCHO increases with reaction 2 5 2 temperature and niobium loading. MMA+MAA selectivity goes through a maximum with the temperature over both 10% and 20% Nb O /SiO . The selectivities to MMA+MAA are 67.2%, 2 5 2 72.3%and 58.1% at 320EC over 5%, 10%, 20% Nb O /SiO , respectively. However, the 2 5 2 conversion of formaldehyde decreases rapidly with time on stream. The results suggest that silica supported niobium catalysts are active and selective for condensation of MP with HCHO, but deactivation needs to be minimized for the consideration of commercial application. We have preliminarily investigated the partial oxidation of dimethyl ether(DME) over 5% Nb O /SiO catalyst. Reactant gas mixture of 0.1% DME, 0.1% O and balance nitrogen is 2 5 2 2 studied with temperature ranging from 200°C to 500°C. The conversion of DME first increases with temperature reaching an maximum at 400°C then decreases. The selectivity to HCHO also increases with reaction temperature first. But the selectivity to HCHO decreases at temperature above 350

  4. Deterioration of polymethyl methacrylate dentures in the oral cavity.

    PubMed

    Matsuo, Hiroshi; Suenaga, Hanako; Takahashi, Masatoshi; Suzuki, Osamu; Sasaki, Keiichi; Takahashi, Nobuhiro

    2015-01-01

    Polymethyl methacrylate (PMMA)-made prostheses used in the oral cavity were evaluated by multimodal assessment in order to elucidate the biodeterioration of PMMA. In used dentures (UD), the micro-Vickers hardness of the polished denture surface and denture basal surface was lower than that of the torn surface (p<0.05), whereas the shaved surface approximately 100 µm from the polished surface showed a similar value to the torn surface. By contrast, there were no differences among these surfaces in new resin (NR). The volatile content of UD was higher than that of NR (p<0.05). Component analysis by ATR-FTIR showed specific spectra (1,700-1,400 cm(-1)) only in UD. This study revealed that PMMA deteriorated during long-term use in the oral cavity in terms of hardness and volatile content with component alteration, and suggests the involvement of biodeterioration, possibly due to saliva and oral microbiota.

  5. Chest wall reconstruction with methacrylate prosthesis in Poland syndrome.

    PubMed

    Arango Tomás, Elisabet; Baamonde Laborda, Carlos; Algar Algar, Javier; Salvatierra Velázquez, Angel

    2013-10-01

    Poland syndrome is a rare congenital malformation. This syndrome was described in 1841 by Alfred Poland at Guy's Hospital in London. It is characterized by hypoplasia of the breast and nipple, subcutaneous tissue shortages, lack of the costosternal portion of the pectoralis major muscle and associated alterations of the fingers on the same side. Corrective treatment of the chest and soft tissue abnormalities in Poland syndrome varies according to different authors. We report the case of a 17-year-old adolescent who underwent chest wall reconstruction with a methyl methacrylate prosthesis. This surgical procedure is recommended for large anterior chest wall defects, and it prevents paradoxical movement. Moreover it provides for individual remodeling of the defect depending on the shape of the patient's chest. PMID:23453291

  6. Radiation synthesis of nanosilver nanohydrogels of poly(methacrylic acid)

    NASA Astrophysics Data System (ADS)

    Gupta, Bhuvanesh; Gautam, Deepti; Anjum, Sadiya; Saxena, Shalini; Kapil, Arti

    2013-11-01

    Nanosilver nanohydrogels (nSnH) of poly(methacrylic acid) were synthesized and stabilized using gamma irradiation. The main objective of this study was to develop silver nanoparticles and to evaluate the antimicrobial activity. Radiation helps in the polymerization, crosslinking and reduction of silver nitrate as well. Highly stable and uniformly distributed silver nanoparticles have been obtained within hydrogel network by water in oil nanoemulsion polymerization and were evaluated by dynamic light scattering (DLS) and transmission electron microscopy (TEM) respectively. TEM showed almost spherical and uniform distribution of silver nanoparticles through the hydrogel network. The mean size of silver nanoparticles ranging is 10-50 nm. The nanohydrogels showed good swelling in water. Antibacterial studies of nSnH suggest that it can be a good candidate as coating material in biomedical applications.

  7. Fabrication of electrospun poly (methyl methacrylate) nanofiber membranes

    NASA Astrophysics Data System (ADS)

    Sethupathy, M.; Sethuraman, V.; Manisankar, P.

    2013-02-01

    Electrospun nanofiber of poly(methyl methacrylate) (PMMA) was fabricated with different concentrations of polymer solution and the optimum concentration arrived at was 15 wt %. The surface morphology of the electrospun membrane was observed by scanning electron microscopy. It consist of thin fibers with an average diameter of about 200-450 nm. The images revealed that the nanofibers showed uniform diameter and no bead formation was observed. Impedance measurements were done for the membranes. PMMA nanofiber membrane showed an ionic conductivity of 1.53 × 10-3 Scm-1 at room temperature. FTIR results confirmed that there was no chemical change in the polymer. The results suggested that electrolyte uptake, ionic conduction and thermal behavior were improved for the PMMA electrospun nanofiber. Hence these nanofibres can very well be employed for the construction of dye-sensitized solar cells and Lithium batteries.

  8. Interaction between N-vinylpyrrolidone and methyl methacrylate

    NASA Astrophysics Data System (ADS)

    Zaitseva, V. V.; Shtonda, A. V.; Tyurina, T. G.; Bagdasarova, A. R.; Zaitsev, S. Yu.

    2014-04-01

    It is established that the interaction of the isomers of N-vinylpyrrolidone (NVP) and methyl methacrylate (MMA) leads to the formation of molecular π-H- and H-complexes with energies within the limits of 10.2-13.6 (AM1) or 18.2-24.0 (B3LYP/6-311++G( d)) kJ/mol. The structures of complex-bound molecules are examined with respect to changes in the charges on terminal -C1=C2- groups, the distance between them and atoms in an H-bond, and the presence of combined overlapping molecular orbitals (MOs). The presence of an averaged complex that includes presumably all possible structures and allows us to perform the copolymerization of specified monomers in the absence of an initiator is confirmed by means of UV and NMR spectroscopy.

  9. Chest wall reconstruction with methacrylate prosthesis in Poland syndrome.

    PubMed

    Arango Tomás, Elisabet; Baamonde Laborda, Carlos; Algar Algar, Javier; Salvatierra Velázquez, Angel

    2013-10-01

    Poland syndrome is a rare congenital malformation. This syndrome was described in 1841 by Alfred Poland at Guy's Hospital in London. It is characterized by hypoplasia of the breast and nipple, subcutaneous tissue shortages, lack of the costosternal portion of the pectoralis major muscle and associated alterations of the fingers on the same side. Corrective treatment of the chest and soft tissue abnormalities in Poland syndrome varies according to different authors. We report the case of a 17-year-old adolescent who underwent chest wall reconstruction with a methyl methacrylate prosthesis. This surgical procedure is recommended for large anterior chest wall defects, and it prevents paradoxical movement. Moreover it provides for individual remodeling of the defect depending on the shape of the patient's chest.

  10. Laser processing of poly(methyl methacrylate) Lambertian diffusers

    NASA Astrophysics Data System (ADS)

    Bubb, Daniel M.; Yi, Sunyong; Kuchmek, John; Corgan, Jeffrey; Papantonakis, Michael

    2010-10-01

    Matrix-assisted pulsed laser deposition was used to deposit poly(methyl methacrylate) on silicon wafers and sodium silicate glass slides for the purpose of making optical diffusers. After deposition, the reflectance of the coated substrates was measured as a function of scattering angle. We found that the angular dependence of the reflectance could be described as the sum of two functions. First, a Gaussian describes the specular reflection of the underlying substrate that has been broadened by passage through the film. Second, a cosine function describes the reflectance contribution from the film itself. We found that by increasing the thickness of the deposited film that we could eliminate the specular reflection to obtain Lambertian diffusers. Since we can control the surface roughness by adjusting the ratio of the two matrices in laser processing, this deposition technique offers the possibility of producing a wide range of diffusers of different types.

  11. Accuracy of adaptation of thermoformed poly(methyl methacrylate).

    PubMed

    Jagger, R G; Milward, P J; Jagger, D C; Vowles, R W

    2003-04-01

    Thermoformed poly(methyl methacrylate) (PMMA) sheet is used to produce a number of different dental appliances such as stents, occlusal splints and baseplates for occlusal rims. The purpose of the present study was to measure the accuracy of adaptation of Perspex PMMA sheet and to determine the effect of annealing on the accuracy of the thermoformed specimens. The results of the study showed that PMMA can produce specimens that are accurately adapted to the cast. Immersion in water resulted in an increase in the space between the cast and the specimen for both thermoformed and thermoformed and annealed acrylic resin. Annealing of the thermoformed specimens had significantly less increase in space between the cast and the specimens when immersed in water over a period of 3 months.

  12. Synthesis of acrylates and Methacrylates from Coal-Derived Syngas

    SciTech Connect

    1997-05-12

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy, Federal Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the propionate synthesis step. The resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees} C and 180 atm). Bechtel has performed an extensive cost analysis which shows that Eastman`s propionate synthesis step is competitive with other technologies to produce the anhydride. Eastman and Bechtel have also compared the RTI- Eastman-Bechtel three-step methanol route to five other process routes to MMA. The results show that the product MMA can be produced at 520/lb, for a 250 Mlb/year MMA plant, and this product cost is competitive to all other process routes to MMA, except propyne carbonylation. In the second step, RTI and Eastman have developed active and stable V-SI-P tertiary metal oxide catalysts, Nb/Si0{sub 2}, and Ta/Si0{sub 2} catalysts for condensation of propionic anhydride or propionic acid with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst performance. Eastman and Bechtel have used the RTI experimental results of a 20 percent Nb/Si0{sub 2} catalyst, in terms of reactant conversions, MAA selectivities, and MAA yield, for their economic analysis. Recent research focuses on enhancing the condensation reaction yields, a better understanding of the acid-base property correlation and enhancing the catalyst lifetime.

  13. Synthesis of Methyl Methacrylate From Coal-Derived Syngas

    SciTech Connect

    Ben W.-L. Jang; Gerald N. Choi; James J. Spivey; Jospeh R. Zoeller; Richard D. Colberg; Samuel S. Tam

    1998-07-27

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter(April-June, 1998), RTI has modified the reactor system including a new preheater and new temperature settings for the preheater. Continuous condensation of formaldehyde with propionic acid were carried out over 10% Nb O /SiO at 300°C without 2 5 2 interruption. Five activity and four regeneration cycles have been completed without plugging or material balance problems. The results show that 10% Nb O /SiO deactivates slowly with time 2 5 2 but can be regenerated, at least four times, to 100% of its original activity with 2% O in nitrogen 2 at 400°C. The cycles continue with consistent 90-95% of carbon balance. The reaction is scheduled to complete with 6 activity cycles and 5 regenerations. Used catalysts will be analyzed with TGA and XPS to determine bulk and surface coke content and coke properties. RTI will start the investigation of effects of propionic acid/formaldehyde ratio on reaction activity and product selectivity over 20% Nb O /SiO catalysts.

  14. Macrophage response to methacrylate conversion using a gradient approach.

    PubMed

    Lin, Nancy J; Bailey, LeeAnn O; Becker, Matthew L; Washburn, Newell R; Henderson, Lori A

    2007-03-01

    Incomplete conversion, an ongoing challenge facing photopolymerized methacrylate-based polymers, affects leachables as well as the resulting polymer network. As novel polymers and composites are developed, methods to efficiently screen cell response to these materials and their properties, including conversion, are needed. In this study, an in vitro screening methodology was developed to assess cells cultured directly on cross-linked polymer networks. A gradient in methacrylate double bond conversion was used to increase the experimental throughput. A substrate of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl] propane (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) was prepared with a conversion ranging from 43.0% to 61.2%. Substrates aged for 7 days had no significant differences in surface roughness or hydrophilicity as a function of conversion. Leachables were detectable for at least 7 days using UV absorption, but their global cytotoxicity was insignificant after 5 days of aging. Thus, RAW 264.7 macrophage-like cells were cultured on aged substrates to evaluate the cell response to conversion, with possible contributions from the polymer network and local leachables. Conversions of 45% and 50% decreased viability (via calcein/ethidium staining) and increased apoptosis (via annexin-V staining). No significant changes (p>0.05) in tumor necrosis factor-alpha and interleukin-1beta gene expression, as measured by quantitative, real-time reverse transcription-polymerase chain reaction, were seen as conversion increased. Thus, conversions greater than 50% are recommended for equimolar BisGMA/TEGDMA. The ability to distinguish cell response as a function of conversion is useful as an initial biological screening platform to optimize dental polymers.

  15. Functional Human Vascular Network Generated in Photocrosslinkable Gelatin Methacrylate Hydrogels.

    PubMed

    Chen, Ying-Chieh; Lin, Ruei-Zeng; Qi, Hao; Yang, Yunzhi; Bae, Hojae; Melero-Martin, Juan M; Khademhosseini, Ali

    2012-05-23

    The generation of functional, 3D vascular networks is a fundamental prerequisite for the development of many future tissue engineering-based therapies. Current approaches in vascular network bioengineering are largely carried out using natural hydrogels as embedding scaffolds. However, most natural hydrogels present a poor mechanical stability and a suboptimal durability, which are critical limitations that hamper their widespread applicability. The search for improved hydrogels has become a priority in tissue engineering research. Here, the suitability of a photopolymerizable gelatin methacrylate (GelMA) hydrogel to support human progenitor cell-based formation of vascular networks is demonstrated. Using GelMA as the embedding scaffold, it is shown that 3D constructs containing human blood-derived endothelial colony-forming cells (ECFCs) and bone marrow-derived mesenchymal stem cells (MSCs) generate extensive capillary-like networks in vitro. These vascular structures contain distinct lumens that are formed by the fusion of ECFC intracellular vacuoles in a process of vascular morphogenesis. The process of vascular network formation is dependent on the presence of MSCs, which differentiate into perivascular cells occupying abluminal positions within the network. Importantly, it is shown that implantation of cell-laden GelMA hydrogels into immunodeficient mice results in a rapid formation of functional anastomoses between the bioengineered human vascular network and the mouse vasculature. Furthermore, it is shown that the degree of methacrylation of the GelMA can be used to modulate the cellular behavior and the extent of vascular network formation both in vitro and in vivo. These data suggest that GelMA hydrogels can be used for biomedical applications that require the formation of microvascular networks, including the development of complex engineered tissues.

  16. Monitoring of acid-base status of workers at a methyl methacrylate and polymethyl methacrylate production plant in Bulgaria.

    PubMed

    Prakova, Gospodinka R

    2003-01-01

    This study was carried out on 104 workers at three work operations and a control (nonproduction) area, within a methyl methacrylate (MMA)/polymethyl methacrylate (PMMA) production facility in Bulgaria. Airborne monitoring was conducted over a 10-year period for MMA and the reactant chemicals methanol and acetone cyanhydrine at the MMA operation, and MMA was monitored at the PMMA operation. Acid-base status of the workers was evaluated using traditional criteria (pH, pCO(2), pO(2), and HCO(3) in plasma). Data from retrospective monitoring of air levels of the chemicals were compared with the acid-base status of workers at the plant. In some cases air concentrations exceeded the threshold limit value, with the highest percentage of overexposure occurring with airborne MMA in the PMMA production operation. Acid-base disruption indicated by reductions in plasma pH and HCO(3) was found for all groups except the control population. The highest percentage reduction was associated with PMMA production workers. Additionally, respiratory acidosis, indicated by increased pCO(2), was noted in the MMA production and maintenance groups, implying that the response to MMA exposure may involve both the metabolic and respiratory acidosis component. This study was unique in that the combined exposure to MMA and the precursor chemical (methanol) were shown to produce the same effects in workers. It is suggested that when combined exposure occurs, disruption of acid-base status may occur. Enforcement of PPM requirements for coveralls and gloves should prevent skin contamination. Additionally, improvement of equipment in MMA and PMMA production areas is recommended: (1) automation of some manual operations; (2) use of respiratory protection during equipment cleaning; and (3) installation of local ventilation when applicable.

  17. Magnetic hydrophilic methacrylate-based polymer microspheres designed for polymerase chain reactions applications.

    PubMed

    Spanová, Alena; Horák, Daniel; Soudková, Eva; Rittich, Bohuslav

    2004-02-01

    Magnetic hydrophilic non-porous P(HEMA-co-EDMA), P(HEMA-co-GMA) and PGMA microspheres were prepared by dispersion (co)polymerization of 2-hydroxyethyl methacrylate (HEMA) and ethylene dimethacrylate (EDMA) or glycidyl methacrylate (GMA) in the presence of several kinds of magnetite. It was found that some components used in the preparation of magnetic carriers interfered with polymerase chain reaction (PCR). Influence of non-magnetic and magnetic microspheres, including magnetite nanoparticles and various components used in their synthesis, on the PCR course was thus investigated. DNA isolated from bacterial cells of Bifidobacterium longum was used in PCR evaluation of non-interfering magnetic microspheres. The method enabled verification of the incorporation of magnetite nanoparticles in the particular methacrylate-based polymer microspheres and evaluation of suitability of their application in PCR. Preferably, electrostatically stabilized colloidal magnetite (ferrofluid) should be used in the design of new magnetic methacrylate-based microspheres by dispersion polymerization. PMID:14698232

  18. 21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...(hydroxyethyl methacrylate)-dye copolymers. (a) Identity. The color additives are formed by reacting one or more... sulfate group (or groups) or chlorine substituent of the dye is replaced by an ether linkage to...

  19. 21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...(hydroxyethyl methacrylate)-dye copolymers. (a) Identity. The color additives are formed by reacting one or more... sulfate group (or groups) or chlorine substituent of the dye is replaced by an ether linkage to...

  20. 21 CFR 73.3121 - Poly(hydroxyethyl methacrylate)-dye copolymers.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...(hydroxyethyl methacrylate)-dye copolymers. (a) Identity. The color additives are formed by reacting one or more... sulfate group (or groups) or chlorine substituent of the dye is replaced by an ether linkage to...

  1. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    Makarand R. Gogate; James J. Spivey; Joseph R. Zoeller; Richard D. Colberg; Gerald N. Choi

    1999-07-19

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. The research team has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, we are currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. During the April-June quarter(04-06/99) the first in-situ formaldehyde generation from DME and condensation with methyl propionate is demonstrated and the results are summarized. The supported niobium catalyst shows better condensation activity, but supported tungsten catalyst has higher formaldehyde selectivity. The project team has also completed a 200-hour long term test of PA-HCHO condensation over 30% Nb{sub 2}O{sub 5}/SiO{sub 2}. Three activity cycles and two regeneration cycles were carried out. 30% Nb{sub 2}O{sub 5}/SiO{sub 2} showed similar MAA yields as 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. However, the deactivation appears to be slower with 30% Nb{sub 2}O{sub 5}/SiO{sub 2} than 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. An detailed economic analysis of PA-HCHO condensation process for a 250 million lb/yr MMA plant is currently studied by Bechtel. Using the Amoco data-based azeotropic distillation model as the basis, an ASPEN flow sheet model was constructed to simulate the formaldehyde and propionic acid condensation processing section based on RTI's design data. The RTI MAA effluent azeotropic distillation column was found to be much more difficult to converge. The presence of non-condensible gases along with the byproduct DEK (both of which were not presented in

  2. Synthesis of Acrylates and Methacrylates from Coal-Derived Syngas.

    SciTech Connect

    Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.; Colberg, R.D.; Choi, G.N.; Tam, S.S.

    1997-10-17

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the U.S. Department of Energy/Federal Energy Technology Center (DOE/FETC). This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Over the last quarter, RTI carried out activity tests on a pure (99 percent) Nb{sub 2}O{sub 5} catalyst, received from Alfa Aesar, under the following experimental conditions: T=300 C; P=4 atm, 72:38:16:4:220 mmol/h, PA:H{sub 2}0:HCHO:CH{sub 3}0H:N{sub 2}; 5-g catalyst charge. For the pure material, the MAA yields (based on HCHO and PA) were at 8.8 and 1.5 percent, clearly inferior compared to those for a 10-percent Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst (20.1 and 4.5 percent). The X-ray diffraction (XRD) patterns of pure Nb{sub 2}O{sub 5} and 20-percent Nb{sub 2}O{sub 5}/Si0{sub 2} that while pure Nb{sub 2}O{sub 5} is very highly crystalline, Si0{sub 2} support for an amorphous nature of the 20 percent Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst the last quarter, RTI also began research on the use of dimethyl ether (DME), product of methanol dehydrocondensation, as an alternate feedstock in MMA synthesis. As a result, formaldehyde is generated either externally or in situ, from DME, in the process envisaged in the contract extension. The initial work on the DME extension of the contract focuses on a tradeoff analysis that will include a preliminary economic analysis of the DME and formaldehyde routes and catalyst synthesis and testing for DME partial oxidation and condensation reactions. Literature guides exist for DME partial oxidation catalysts; however, there are no precedent studies on catalyst development for DME-methyl propionate (MP) condensation reactions, thereby making DME-MP reaction studies a

  3. SYNTHESIS OF METHYL METHACRYLATE FROM COAL-DERIVED SYNGAS

    SciTech Connect

    BEN W.-L. JANG; GERALD N. CHOI; JAMES J. SPIVEY; JOSPEH R. ZOELLER; RICHARD D. COLBERG

    1998-10-20

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel three-step process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of the steps of synthesis of a propionate, its condensation with formaldehyde to form methacrylic acid (MAA), and esterification of MAA with methanol to produce MMA. RTI has completed the research on the three-step methanol-based route to MMA. Under an extension to the original contract, RTI is currently evaluating a new DME-based process for MMA. The key research need for DME route is to develop catalysts for DME partial oxidation reactions and DME condensation reactions. Over the last quarter (July-September, 1998), the project team has completed the continuous condensation of formaldehyde with propionic acid over 10% Nb{sub 2}O{sub 5}/SiO{sub 2} at 300 C. Six activity and five regeneration cycles have been completed. The results show that 10% Nb{sub 2}O{sub 5}/SiO{sub 2} deactivates slowly with time but can be regenerated to its original activity with 2% O{sub 2} in nitrogen over night at 400 C. We have investigated the effects of regeneration, propionic acid/formaldehyde ratio (PA/HCHO = 4.5/1 to 1.5/1) and reaction temperature(280-300 C) on reaction activity and product selectivity over 20% Nb{sub 2}O{sub 5}/SiO{sub 2} catalysts. The regeneration effect on 20% Nb{sub 2}O{sub 5}/SiO{sub 2} is similar to the effect on 10% Nb{sub 2}O{sub 5}/SiO{sub 2}. The regeneration can bring the deactivated catalyst to its original activity. However, the selectivity to MAA decreases with regeneration while the selectivity to DEK and CO{sub 2} increases. When PA/HCHO ratio is decreased from 4.5/1 to 2.25/1 then to 1.5/1 at 300 C the MAA yield decreases but the MAA selectivity first increases then decreases. Decreasing the reaction temperature from 300 C to 280 C decreases the MAA yield from 39.5% to 30.7% but increases the MAA selectivity from 73.7% to 82.2%. The

  4. Novel catalysts for the environmentally friendly synthesis of methyl methacrylate

    SciTech Connect

    Spivey, J.J.; Gogate, M.R.; Zoeller, J.R.; Colberg, R.D.

    1997-11-01

    The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) to form MMA. The first two steps, propionic acid synthesis and condensation, are discussed here. The low-temperature, low-pressure process for single-step hydrocarbonylation of ethylene to propionic acid is carried out using a homogeneous iodine-promoted Mo(CO){sub 6} catalyst at pressures (30--70 atm) and temperatures (150--200 C) lower than those reported for other catalysts. Mechanistic investigations suggest that catalysis is initiated by a rate-limiting CO dissociation from Mo(CO){sub 6}. This dissociation appears to be followed by an inner electron-transfer process of an I atom from EtI to the coordinately unsaturated Mo(CO){sub 5}. This homogeneous catalyst for propionate synthesis represents the first case of an efficient carbonylation process based on Cr group metals. The condensation of formaldehyde with propionic acid is carried out by acid-base bifunctional catalysts. As a result of screening over 80 catalytic materials, group V metals supported on an amorphous silica are found to be most effective. A 20% Nb/SiO{sub 2} catalyst appears to be the most active and stable catalyst thus far. Preliminary relations among the reaction yield and catalyst properties indicate that a high surface area and a low overall surface acidity (<50 = mol of NH{sub 3}/g), with a high proportion of the acidity being weak (<350 C desorption of NH{sub 3}), are desirable. Long-term deactivation of V-Si-P, Nb-Si, and Ta-Si catalysts suggests that carbon deposition is the primary cause for activity decay, and the catalyst activity is partially restorable by oxidative regeneration.

  5. Staining methods applied to glycol methacrylate embedded tissue sections.

    PubMed

    Cerri, P S; Sasso-Cerri, E

    2003-01-01

    The use of glycol methacrylate (GMA) avoids some technical artifacts, which are usually observed in paraffin-embedded sections, providing good morphological resolution. On the other hand, weak staining have been mentioned during the use of different methods in plastic sections. In the present study, changes in the histological staining procedures have been assayed during the use of staining and histochemical methods in different GMA-embedded tissues. Samples of tongue, submandibular and sublingual glands, cartilage, portions of respiratory tract and nervous ganglion were fixed in 4% formaldehyde and embedded in glycol methacrylate. The sections of tongue and nervous ganglion were stained by H&E. Picrosirius, Toluidine Blue and Sudan Black B methods were applied, respectively, for identification of collagen fibers in submandibular gland, sulfated glycosaminoglycans in cartilage (metachromasia) and myelin lipids in nervous ganglion. Periodic Acid-Schiff (PAS) method was used for detection of glycoconjugates in submandibular gland and cartilage while AB/PAS combined methods were applied for detection of mucins in the respiratory tract. In addition, a combination of Alcian Blue (AB) and Picrosirius methods was also assayed in the sublingual gland sections. The GMA-embedded tissue sections showed an optimal morphological integrity and were favorable to the staining methods employed in the present study. In the sections of tongue and nervous ganglion, a good contrast of basophilic and acidophilic structures was obtained by H&E. An intense eosinophilia was observed either in the striated muscle fibers or in the myelin sheaths in which the lipids were preserved and revealed by Sudan Black B. In the cartilage matrix, a strong metachromasia was revealed by Toluidine Blue in the negatively-charged glycosaminoglycans. In the chondrocytes, glycogen granules were intensely positive to PAS method. Extracellular glycoproteins were also PAS positive in the basal membrane and in the

  6. Barrier layers against oxygen transmission on the basis of electron beam cured methacrylated gelatin

    NASA Astrophysics Data System (ADS)

    Scherzer, Tom

    1997-08-01

    The development of barrier layers against oxygen transmission on the basis of radiation-curable methacrylated gelatin will be reported. The electron beam cured gelatin coatings show an extremely low oxygen permeability and a high resistance against boiling water. Moreover, the methacrylated gelatins possess good adhesion characteristics. Therefore, they are suited as barrier adhesives in laminates for food packaging applications. If substrate foils from biodegradable polymers are used, the development of completely biodegradable packaging materials seems to be possible.

  7. Transparent and luminescent ionogels composed of Eu(3+)-coordinated ionic liquids and poly(methyl methacrylate).

    PubMed

    Zhou, Fan; Wang, Tianren; Li, Zhiqiang; Wang, Yige

    2015-12-01

    We report here on transparent and luminescent ionogels that consist of ionic ternary europium (III) complexes and the inexpensive non-toxic compound, poly(methyl methacrylate) (PMMA) and that were formed by dissolving these complexes in methacrylate (MMA) monomers followed by in situ polymerization. The resulting ionogels show a bright red emission under near-UV light irradiation. Luminescence data confirm the energy transfer from terpyridine-functionalized ionic liquid to Eu(3+) ions.

  8. Holographic Recording in Methacrylate Photopolymer Film Codoped with Benzyl n-Butyl Phthalate and Silica Nanoparticles

    NASA Astrophysics Data System (ADS)

    Takahashi, Hiroshi; Naito, Takahiro; Tomita, Yasuo

    2006-06-01

    Transmission volume holograms recorded in methacrylate photopolymer films codoped with benzyl n-butyl phthalate (BBP) and silica nanoparticles are studied. It is found that BBP, which is a well-known plasticizer, can be directly mixed with methacrylate monomer and that a refractive index modulation as high as ˜0.006 is recorded with a BBP concentration of 36 vol %. It is also found that the additional dispersion of silica nanoparticles substantially suppresses polymerization shrinkage without increasing optical scattering loss.

  9. The siloxane bond in contact lens materials: the siloxanyl alkyl methacrylate copolymers.

    PubMed

    Refojo, M F

    1984-11-01

    The siloxanyl alkyl methacrylate copolymers with methyl methacrylate and other components including hydrophilic monomers and crosslinking agents are used to make siloxane methacrylate oxygen-permeable rigid contact lenses. These copolymers contain the element silicon as siloxane bonds in side branches of the main polymer chain, which is made of carbon-to-carbon bonds. The siloxane bonds are the main contributing factor to the oxygen permeability of these materials. Because silicone is not a component of these contact lenses, it is not appropriate to refer to them as silicone methacrylate contact lenses. This paper analyzes data from three fundamental patents and gives the oxygen permeability coefficients of three types of siloxanyl alkyl methacrylate copolymers. In one type the siloxanyl component contains two silicon atoms, in the second type it contains three silicon atoms, and in the third type it contains four silicon atoms. A general relationship, expressed by a power function, is developed between the oxygen permeability coefficients of siloxanyl alkyl methacrylate copolymers and dimethylsilicone rubber and their percent disiloxane or silicon content. PMID:6517434

  10. In vivo genotoxicity assessment of acrylamide and glycidyl methacrylate.

    PubMed

    Dobrovolsky, Vasily N; Pacheco-Martinez, M Monserrat; McDaniel, L Patrice; Pearce, Mason G; Ding, Wei

    2016-01-01

    Acrylamide (ACR) and glycidyl methacrylate (GMA) are structurally related compounds used for making polymers with various properties. Both chemicals can be present in food either as a byproduct of processing or a constituent of packaging. We performed a comprehensive evaluation of ACR and GMA genotoxicity in Fisher 344 rats using repeated gavage administrations. Clastogenicity was measured by scoring micronucleated (MN) erythrocytes from peripheral blood, DNA damage in liver, bone marrow and kidneys was measured using the Comet assay, and gene mutation was measured using the red blood cell (RBC) and reticulocyte Pig-a assay. A limited histopathology evaluation was performed in order to determine levels of cytotoxicity. Doses of up to 20 mg/kg/day of ACR and up to 250 mg/kg/day of GMA were used. ACR treatment resulted in DNA damage in the liver, but not in the bone marrow. While ACR was not a clastogen, it was a weak (equivocal) mutagen in the cells of bone marrow. GMA caused DNA damage in the cells of bone marrow, liver and kidney, and induced MN reticulocytes and Pig-a mutant RBCs in a dose-dependent manner. Collectively, our data suggest that both compounds are in vivo genotoxins, but the genotoxicity of ACR is tissue specific.

  11. Ageing and moisture uptake in polymethyl methacrylate (PMMA) bone cements☆

    PubMed Central

    Ayre, Wayne Nishio; Denyer, Stephen P.; Evans, Samuel L.

    2014-01-01

    Bone cements are extensively employed in orthopaedics for joint arthroplasty, however implant failure in the form of aseptic loosening is known to occur after long-term use. The exact mechanism causing this is not well understood, however it is thought to arise from a combination of fatigue and chemical degradation resulting from the hostile in vivo environment. In this study, two commercial bone cements were aged in an isotonic fluid at physiological temperatures and changes in moisture uptake, microstructure and mechanical and fatigue properties were studied. Initial penetration of water into the cement followed Fickian diffusion and was thought to be caused by vacancies created by leaching monomer. An increase in weight of approximately 2% was experienced after 30 days ageing and was accompanied by hydrolysis of poly(methyl methacrylate) (PMMA) in the outermost layers of the cement. This molecular change and the plasticising effect of water resulted in reduced mechanical and fatigue properties over time. Cement ageing is therefore thought to be a key contributor in the long-term failure of cemented joint replacements. The results from this study have highlighted the need to develop cements capable of withstanding long-term degradation and for more accurate test methods, which fully account for physiological ageing. PMID:24445003

  12. Directed endothelial cell morphogenesis in micropatterned gelatin methacrylate hydrogels.

    PubMed

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2012-12-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50-150 μm height). We demonstrated the significant dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 μm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs.

  13. Directed Endothelial Cell Morphogenesis in Micropatterned Gelatin Methacrylate Hydrogels

    PubMed Central

    Nikkhah, Mehdi; Eshak, Nouran; Zorlutuna, Pinar; Annabi, Nasim; Castello, Marco; Kim, Keekyoung; Dolatshahi-Pirouz, Alireza; Edalat, Faramarz; Bae, Hojae; Yang, Yunzhi; Khademhosseini, Ali

    2013-01-01

    Engineering of organized vasculature is a crucial step in the development of functional and clinically relevant tissue constructs. A number of previous techniques have been proposed to spatially regulate the distribution of angiogenic biomolecules and vascular cells within biomaterial matrices to promote vascularization. Most of these approaches have been limited to two-dimensional (2D) micropatterned features or have resulted in formation of random vasculature within three-dimensional (3D) microenvironments. In this study, we investigate 3D endothelial cord formation within micropatterned gelatin methacrylate (GelMA) hydrogels with varying geometrical features (50–150 µm height). We demonstrated the significance dependence of endothelial cells proliferation, alignment and cord formation on geometrical dimensions of the patterned features. The cells were able to align and organize within the micropatterned constructs and assemble to form cord structures with organized actin fibers and circular/elliptical cross-sections. The inner layer of the cord structure was filled with gel showing that the micropatterned hydrogel constructs guided the assembly of endothelial cells into cord structures. Notably, the endothelial cords were retained within the hydrogel microconstructs for all geometries after two weeks of culture; however, only the 100 µm-high constructs provided the optimal microenvironment for the formation of circular and stable cord structures. Our findings suggest that endothelial cord formation is a preceding step to tubulogenesis and the proposed system can be used to develop organized vasculature for engineered tissue constructs. PMID:23018132

  14. Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification.

    PubMed

    Bux, Jaiyana; Manga, Mohamed S; Hunter, Timothy N; Biggs, Simon

    2016-07-28

    Accurate control of particle size at relatively narrow polydispersity remains a key challenge in the production of synthetic polymer particles at scale. A cross-flow membrane emulsification (XME) technique was used here in the preparation of poly(methyl methacrylate) microspheres at a 1-10 l h(-1) scale, to demonstrate its application for such a manufacturing challenge. XME technology has previously been shown to provide good control over emulsion droplet sizes with careful choice of the operating conditions. We demonstrate here that, for an appropriate formulation, equivalent control can be gained for a precursor emulsion in a batch suspension polymerization process. We report here the influence of key parameters on the emulsification process; we also demonstrate the close correlation in size between the precursor emulsion and the final polymer particles. Two types of polymer particle were produced in this work: a solid microsphere and an oil-filled matrix microcapsule.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'.

  15. Thermal Properties of Polymethyl Methacrylate Composite Containing Copper Nanoparticles.

    PubMed

    Yu, Wei; Xie, Huaqing; Xin, Sha; Yin, Junshan; Jiang, Yitong; Wang, Mingzhu

    2015-04-01

    Thermal functional Materials have wide applications in thermal management fields, and inserting highly thermal conductive materials is effective in enhancing thermal conductivity of matrix. In this paper, copper nanoparticles were selected as the additive to prepare polymethyl methacrylate (PMMA) based nanocomposite with enhanced thermal properties. Uniform copper nanoparticles with pure face-centered lattice were prepared by liquid phase reduction method. Then, they were added into PMMA/N, N-Dimethylmethanamide (DMF) solution according to the different mass fraction for uniform dispersion. After DMF was evaporated, Cu-PMMA nanocomposites were gained. The thermal analysis measurement results showed that the decomposition temperature of nanocomposites decreased gradually with the increasing particle loadings. The thermal conductivity of the Cu-PMMA nanocomposites rose with the increasing contents of copper nanoparticles. With a 20 vol.% addition, the thermal conductivity was up to 1.2 W/m · K, a 380.5% increase compared to the pure PMMA. The results demonstrate that copper nanoparticles have great potential in enhancing thermal transport properties of polymer.

  16. Methyl methacrylate and respiratory sensitization: A Critical review

    PubMed Central

    Borak, Jonathan; Fields, Cheryl; Andrews, Larry S; Pemberton, Mark A

    2011-01-01

    Methyl methacrylate (MMA) is a respiratory irritant and dermal sensitizer that has been associated with occupational asthma in a small number of case reports. Those reports have raised concern that it might be a respiratory sensitizer. To better understand that possibility, we reviewed the in silico, in chemico, in vitro, and in vivo toxicology literature, and also epidemiologic and occupational medicine reports related to the respiratory effects of MMA. Numerous in silico and in chemico studies indicate that MMA is unlikely to be a respiratory sensitizer. The few in vitro studies suggest that MMA has generally weak effects. In vivo studies have documented contact skin sensitization, nonspecific cytotoxicity, and weakly positive responses on local lymph node assay; guinea pig and mouse inhalation sensitization tests have not been performed. Cohort and cross-sectional worker studies reported irritation of eyes, nose, and upper respiratory tract associated with short-term peaks exposures, but little evidence for respiratory sensitization or asthma. Nineteen case reports described asthma, laryngitis, or hypersensitivity pneumonitis in MMA-exposed workers; however, exposures were either not well described or involved mixtures containing more reactive respiratory sensitizers and irritants.The weight of evidence, both experimental and observational, argues that MMA is not a respiratory sensitizer. PMID:21401327

  17. Spallation Characteristics of Poly-Methyl Meth-Acrylic (PMMA)

    NASA Astrophysics Data System (ADS)

    Bartkowski, Peter; Dandekar, D. P.

    1999-06-01

    This work describes the results derived from plane shock wave spallation experiments performed on Poly-Methyl Meth-Acrylic (PMMA) Polymer. These experiments were conducted using the Army Research Laboratories 102 mm Bore, 8 m long Light Gas Gun located at Aberdeen Proving Ground, MD. The PMMA used in this work was manufactured by Rohm & Haas as their Ultra-Violet Absorbing (UVA), Type II Plexiglass. Its density is 1.188 Mg/m3 and longitudinal shock velocity is 2.72 mm/μ s. Spallation experiments were conducted at impact stresses between 0.2 and 2.0 GPa. The PMMA appears to exhibit a constant tensile strength of 0.15 GPa up to an impact stress of 0.75 GPa. Unlike metal and ceramic materials, the PMMA exhibits a dwell time in the spallation inversly proportional to the impact stress. At a low impact stress of 0.40 GPa, spallation of the PMMA occurs over a time period of 0.80 micro-seconds. At an impact stress of 0.75 GPa, the spallation occurs over 0.40 micro-seconds. This variation in time required to spall the PMMA will be analyzed and theories discussed.

  18. Characterization of methacrylate chromatographic monoliths bearing affinity ligands.

    PubMed

    Černigoj, Urh; Vidic, Urška; Nemec, Blaž; Gašperšič, Jernej; Vidič, Jana; Lendero Krajnc, Nika; Štrancar, Aleš; Podgornik, Aleš

    2016-09-16

    We investigated effect of immobilization procedure and monolith structure on chromatographic performance of methacrylate monoliths bearing affinity ligands. Monoliths of different pore size and various affinity ligands were prepared and characterized using physical and chromatographic methods. When testing protein A monoliths with different protein A ligand densities, a significant nonlinear effect of ligand density on dynamic binding capacity (DBC) for IgG was obtained and accurately described by Langmuir isotherm curve enabling estimation of protein A utilization as a function of ligand density. Maximal IgG binding capacity was found to be at least 12mg/mL exceeding theoretical monolayer adsorption value of 7.8mg/mL assuming hexagonal packing and IgG hydrodynamic diameter of 11nm. Observed discrepancy was explained by shrinkage of IgG during adsorption on protein A experimentally determined through calculated adsorbed IgG layer thickness of 5.4nm from pressure drop data. For monoliths with different pore size maximal immobilized densities of protein A as well as IgG dynamic capacity linearly correlates with monolith surface area indicating constant ligand utilization. Finally, IgGs toward different plasma proteins were immobilized via the hydrazide coupling chemistry to provide oriented immobilization. DBC was found to be flow independent and was increasing with the size of bound protein. Despite DBC was lower than IgG capacity to immobilized protein A, ligand utilization was higher. PMID:27554023

  19. Manufacture of poly(methyl methacrylate) microspheres using membrane emulsification.

    PubMed

    Bux, Jaiyana; Manga, Mohamed S; Hunter, Timothy N; Biggs, Simon

    2016-07-28

    Accurate control of particle size at relatively narrow polydispersity remains a key challenge in the production of synthetic polymer particles at scale. A cross-flow membrane emulsification (XME) technique was used here in the preparation of poly(methyl methacrylate) microspheres at a 1-10 l h(-1) scale, to demonstrate its application for such a manufacturing challenge. XME technology has previously been shown to provide good control over emulsion droplet sizes with careful choice of the operating conditions. We demonstrate here that, for an appropriate formulation, equivalent control can be gained for a precursor emulsion in a batch suspension polymerization process. We report here the influence of key parameters on the emulsification process; we also demonstrate the close correlation in size between the precursor emulsion and the final polymer particles. Two types of polymer particle were produced in this work: a solid microsphere and an oil-filled matrix microcapsule.This article is part of the themed issue 'Soft interfacial materials: from fundamentals to formulation'. PMID:27298430

  20. Properties of holographic gratings photoinduced in polymethyl methacrylate.

    PubMed

    Moran, J M; Kaminow, I P

    1973-08-01

    Polymethyl methacrylate, PMMA, sensitized for lambda = 0.325 microm, is shown to exhibit a peak refractive index change of 2.3 x 10(-3). The index change has been characterized in relation to its sensitivity, temperature dependence, and development time. The sensitivity of the material is shown to be 1.7 x10(-4) alpha, where alpha is the intensity absorption coefficient. Laser light scattered by an exposed region is found to produce a double ring pattern due to the graininess of the index variation. Three-dimensional holographic diffraction gratings were made in the PMMA, and its diffraction efficiency was measured as a function of thickness, refractive index change, and reconstruction angle. The efficiencies measured agree fairly well with the theoretical sin(2) curve; however, higher peak diffraction efficiencies were obtained further out on this oscillatory curve. A maximum diffraction efficiency of 96% was obtained. Angular sensitivity measurements indicated that the effective thickness of the grating was less than its actual thickness due to the nonuniformity of the index variation with thickness. Potential applications as a dielectric waveguide, diffraction grating, and wavelength selector are discussed. Scattering, the relatively small maximum index change, and poor reproducibility are the chief limiting factors.

  1. Poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) Brushes as Peptide/Protein Microarray Substrate for Improving Protein Binding and Functionality.

    PubMed

    Lei, Zhen; Gao, Jiaxue; Liu, Xia; Liu, Dianjun; Wang, Zhenxin

    2016-04-27

    We developed a three-dimensional (3D) polymer-brush substrate for protein and peptide microarray fabrication, and this substrate was facilely prepared by copolymerization of glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) monomers via surface-initiated atom transfer radical polymerization (SI-ATRP) on a glass slide. The performance of obtained poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) (P(GMA-HEMA)) brush substrate was assessed by binding of human IgG with rabbit antihuman IgG antibodies on a protein microarray and by the determination of matrix metalloproteinase (MMP) activities on a peptide microarray. The P(GMA-HEMA) brush substrate exhibited higher immobilization capacities for proteins and peptides than those of a two-dimensional (2D) planar epoxy slide. Furthermore, the sensitivity of the P(GMA-HEMA) brush-based microarray on rabbit antihuman IgG antibody detection was much higher than that of its 2D counterpart. The enzyme activities of MMPs were determined specifically with a low detection limit of 6.0 pg mL(-1) for MMP-2 and 5.7 pg mL(-1) for MMP-9. By taking advantage of the biocompatibility of PHEMA, the P(GMA-HEMA) brush-based peptide microarray was also employed to evaluate the secretion of MMP-2 and MMP-9 by cells cultured off the chip or directly on the chip, and satisfactory results were obtained. PMID:27049528

  2. Poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) Brushes as Peptide/Protein Microarray Substrate for Improving Protein Binding and Functionality.

    PubMed

    Lei, Zhen; Gao, Jiaxue; Liu, Xia; Liu, Dianjun; Wang, Zhenxin

    2016-04-27

    We developed a three-dimensional (3D) polymer-brush substrate for protein and peptide microarray fabrication, and this substrate was facilely prepared by copolymerization of glycidyl methacrylate (GMA) and 2-hydroxyethyl methacrylate (HEMA) monomers via surface-initiated atom transfer radical polymerization (SI-ATRP) on a glass slide. The performance of obtained poly(glycidyl methacrylate-co-2-hydroxyethyl methacrylate) (P(GMA-HEMA)) brush substrate was assessed by binding of human IgG with rabbit antihuman IgG antibodies on a protein microarray and by the determination of matrix metalloproteinase (MMP) activities on a peptide microarray. The P(GMA-HEMA) brush substrate exhibited higher immobilization capacities for proteins and peptides than those of a two-dimensional (2D) planar epoxy slide. Furthermore, the sensitivity of the P(GMA-HEMA) brush-based microarray on rabbit antihuman IgG antibody detection was much higher than that of its 2D counterpart. The enzyme activities of MMPs were determined specifically with a low detection limit of 6.0 pg mL(-1) for MMP-2 and 5.7 pg mL(-1) for MMP-9. By taking advantage of the biocompatibility of PHEMA, the P(GMA-HEMA) brush-based peptide microarray was also employed to evaluate the secretion of MMP-2 and MMP-9 by cells cultured off the chip or directly on the chip, and satisfactory results were obtained.

  3. Can quaternary ammonium methacrylates inhibit matrix MMPs and cathepsins?

    PubMed Central

    Tezvergil-Mutluay, Arzu; Agee, Kelli A.; Mazzoni, Annalisa; Carvalho, Ricardo M.; Carrilho, Marcela; Tersariol, Ivarne L.; Nascimento, Fabio D.; Imazato, Satoshi; Tjäderhane, Leo; Breschi, Lorenzo; Tay, Franklin R; Pashley, David H.

    2014-01-01

    Objective Dentin matrices release ICTP and CTX fragments during collagen degradation. ICTP fragments are known to be produced by MMPs. CTX fragments are thought to come from cathepsin K activity. The purpose of this study was to determine if quaternary methacrylates (QAMs) can inhibit matrix MMPs and cathepsins. Methods Dentin beams were demineralizated, and dried to constant weight. Beams were incubated with rh-cathepsin B, K, L or S for 24 h at pH 7.4 to identify which cathepsins release CTX at neutral pH. Beams were dipped in ATA, an antimicrobial QAM to determine if it can inhibit dentin matrix proteases. Other beams were dipped in another QAM (MDPB) to determine if it produced similar inhibition of dentin proteases. Results Only beams incubated with cathepsin K lost more dry mass than the controls and released CTX. Dentin beams dipped in ATA and incubated for 1 week at pH 7.4, showed a concentration-dependent reduction in weight-loss. There was no change in ICTP release from control values, meaning that ATA did not inhibit MMPs. Media concentrations of CTX fell significantly at 15 wt% ATA indicating that ATA inhibits capthesins. Beams dipped in increasing concentrations of MDPB lost progressively less mass, showing that MDPB is a protease-inhibitor. ICTP released from controls or beams exposed to low concentrations were the same, while 5 or 10% MDPB significantly lowered ICTP production. CTX levels were strongly inhibited by 2.5–10% MDPB, indicating that MDPB is a potent inhibitor of both MMPs and cathepsin K. Significance CTX seems to be released from dentin matrix only by cathepsin K. MMPs and cathepsin K and B may all contribute to matrix degradation. PMID:25467953

  4. Facile Fabrication of Gradient Surface Based on (meth)acrylate Copolymer Films

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Yang, H.; Wen, X.-F.; Cheng, J.; Xiong, J.

    2016-08-01

    This paper describes a simple and economic approach for fabrication of surface wettability gradient on poly(butyl acrylate - methyl methacrylate) [P (BA-MMA)] and poly(butyl acrylate - methyl methacrylate - 2-hydroxyethyl methacrylate) [P (BA-MMA-HEMA)] films. The (meth)acrylate copolymer [including P (BA-MMA) and P (BA-MMA-HEMA)] films are hydrolyzed in an aqueous solution of NaOH and the transformation of surface chemical composition is achieved by hydrolysis in NaOH solution. The gradient wetting properties are generated based on different functional groups on the P (BA-MMA) and P (BA-MMA-HEMA) films. The effects of both the surface chemical and surface topography on wetting of the (meth)acrylate copolymer film are discussed. Surface chemical composition along the materials length is determined by XPS, and surface topography properties of the obtained gradient surfaces are analyzed by FESEM and AFM. Water contact angle system (WCAs) results show that the P (BA-MMA-HEMA) films provide a larger slope of the gradient wetting than P (BA-MMA). Moreover, this work demonstrates that the gradient concentration of chemical composition on the poly(meth) acrylate films is owing to the hydrolysis processes of ester group, and the hydrolysis reactions that have negligible influence on the surface morphology of the poly(meth) acrylate films coated on the glass slide. The gradient wettability surfaces may find broad applications in the field of polymer coating due to the compatibility of (meth) acrylate polymer.

  5. Preparation and characterization of alkyl methacrylate-based monolithic columns for capillary gas chromatography applications.

    PubMed

    Yusuf, Kareem; Aqel, Ahmad; A L Othman, Zeid; Badjah-Hadj-Ahmed, Ahmed Yacine

    2013-08-01

    Gas chromatography (GC) is considered the least common application of both polymer and silica-based monolithic columns. This study describes the fabrication of alkyl methacrylate monolithic materials for use as stationary phases in capillary gas chromatography. Following the deactivation of the capillary surface with 3-(trimethoxysilyl)propyl methacrylate (TMSM), the monoliths were formed by the co-polymerization of either hexyl methacrylate (HMA) or lauryl methacrylate (LMA) with different percentage of ethylene glycol dimethacrylate (EDMA) in presence of an initiator (azobisisobutyronitrile, AIBN) and a mixture of porogens include 1-propanol, 1,4-butanediol and water. The monoliths were prepared in 500mm length capillaries possessing inner diameters of 250μm. The efficiencies of the monolithic columns for low molecular weight compounds significantly improved as the percentage of crosslinker was increased, because of the greater proportion of pores less than 50nm. The columns containing lower percentages of crosslinker were able to rapidly separate a series of 8 alkane members in 0.7min, but the separation was less efficient for the light alkanes. Columns prepared with the lauryl methacrylate monomer yielded a different morphology for the monolith-interconnected channels. The channels were more branched, which increased the separation time, and unlike the other columns, allowed for temperature programming.

  6. 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.

  7. Influencing Factors for Organic Spill Recovery Performance with a Novel Polypropylene-Methacrylate Sorbent.

    PubMed

    Li, Shaoning; Wei, Junfu; Chen, Yuan; Cui, Li; Zhang, Yue; Dai, Zhao; Zhao, Shihuai

    2015-08-01

    Insoluble organic matter released to the water body through accidental spillage imposes serious damage on the environment. Polypropylene (PP) fiber and methacrylate resin, however, end up in certain morphology or low sorption capacity after a single use. In this study, a novel sorbent was prepared by radiation-induced graft polymerization of butyl methacrylate (BMA) onto PP fiber matrix to retain the advantages of both PP fibers and methacrylate resins to overcome the shortcomings of each used alone. The different parameters including irradiation power, irradiation time and monomer concentration that effect the grafting degree of grafted fiber were studied. The resulting grafted fibers (PP-g-BMA) were evaluated in this study in terms of sorption capacity, retention behaviors and reusability properties. The investigation revealed that the homopolymerization rate, organic matter temperature and pH values of organic-over-water aqueous solution are the most important factors in the sorption performance of polypropylene grafted fiber sorbent. PMID:26237685

  8. Effects of surfactants on the properties of mortar containing styrene/methacrylate superplasticizer.

    PubMed

    Negim, El-Sayed; Kozhamzharova, Latipa; Khatib, Jamal; Bekbayeva, Lyazzat; Williams, Craig

    2014-01-01

    The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA.

  9. Chondrocyte Generation of Cartilage-Like Tissue Following Photoencapsulation in Methacrylated Polysaccharide Solution Blends.

    PubMed

    Hayami, James W S; Waldman, Stephen D; Amsden, Brian G

    2016-07-01

    Chondrocyte-seeded, photo-cross-linked hydrogels prepared from solutions containing 50% mass fractions of methacrylated glycol chitosan or methacrylated hyaluronic acid (MHA) with methacrylated chondroitin sulfate (MCS) are cultured in vitro under static conditions over 35 d to assess their suitability for load-bearing soft tissue repair. The photo-cross-linked hydrogels have initial equilibrium moduli between 100 and 300 kPa, but only the MHAMCS hydrogels retain an approximately constant modulus (264 ± 5 kPa) throughout the culture period. Visually, the seeded chondrocytes in the MHAMCS hydrogels are well distributed with an apparent constant viability in culture. Multicellular aggregates are surrounded by cartilaginous matrix, which contain aggrecan and collagen II. Thus, co-cross-linked MCS and MHA hydrogels may be suited for use in an articular cartilage or nucleus pulposus repair applications. PMID:27061241

  10. Effects of Surfactants on the Properties of Mortar Containing Styrene/Methacrylate Superplasticizer

    PubMed Central

    Negim, El-Sayed; Kozhamzharova, Latipa; Khatib, Jamal; Bekbayeva, Lyazzat; Williams, Craig

    2014-01-01

    The physical and mechanical properties of mortar containing synthetic cosurfactants as air entraining agent are investigated. The cosurfactants consist of a combination of 2% dodecyl benzene sodium sulfonate (DBSS) and either 1.5% polyvinyl alcohol (PVA) or 1.5% polyoxyethylene glycol monomethyl ether (POE). Also these cosurfactants were used to prepare copolymers latex: styrene/butyl methacrylate (St/BuMA), styrene/methyl methacrylate (St/MMA), and styrene/glycidyl methacrylate (St/GMA), in order to study their effects on the properties of mortar. The properties of mortar examined included flow table, W/C ratio, setting time, water absorption, compressive strength, and combined water. The results indicate that the latex causes improvement in mortar properties compared with cosurfactants. Also polymer latex containing DBSS/POE is more effective than that containing DBSS/PVA. PMID:24955426

  11. Toughening epoxy resin with poly(methyl methacrylate)-grafted natural rubber

    SciTech Connect

    Rezaifard, A.H.; Hodd, K.A.; Barton, J.M.

    1993-12-31

    A novel rubber, poly(methyl methacrylate)-g-natural rubber (Hevea-plus MG), has been studied as a toughening agent for bisphenol A diglycidyl ether (Shell 828 epoxy resin) cured with piperidine. Effective dispersions of the rubber, in concentrations of 2-10 parts per hundred parts resin, were achieved by adjusting the solubility parameter of the epoxy to approximate that of poly(methyl methacrylate) by adding bisphenol A. The fracture energy of the rubber-modified resin was determined by compact tension tests (in the temperature range -60 to +40{degrees}C) and by Charpy impact tests. The poly(methyl methacrylate)-g-natural rubber was found to be an effective toughening agent for the epoxy resin at both low and high rates of strain. Possible fracture mechanisms are discussed. 22 refs., 16 figs., 5 tabs.

  12. Assessment of the skin sensitising potency of the lower alkyl methacrylate esters.

    PubMed

    Kimber, Ian; Pemberton, Mark A

    2014-10-01

    There is continued interest in, and imperatives for, the classification of contact allergens according to their relative skin sensitising potency. However, achieving that end can prove problematic, not least when there is an apparent lack of concordance between experimental assessments of potency and the prevalence allergic contact dermatitis as judged by clinical experience. For the purpose of exploring this issue, and illustrating the important considerations that are required to reach sound judgements about potency categorisation, the lower alkyl methacrylate esters (LAM) have been employed here as a case study. Although the sensitising potential of methyl methacrylate (MMA) has been reviewed previously, there is available new information that is relevant for assessment of skin sensitising potency. Moreover, for the purposes of this article, analyses have been extended to include also other LAM for which relevant data are available: ethyl methacrylate (EMA), n-butyl methacrylate (nBMA), isobutyl methacrylate (iBMA), and 2-ethylhexyl methacrylate (EHMA). In addressing the skin sensitising activity of these chemicals and in drawing conclusions regarding relative potency, a number of sources of information has been considered, including estimates of potency derived from local lymph node assay (LLNA) data, the results of guinea pig assays, and data derived from in silico methods and from recently developed in vitro approaches. Moreover, clinical experience of skin sensitisation of humans by LAM has also been evaluated. The conclusion drawn is that MMA and other LAM are contact allergens, but that none of these chemicals has any more than weak skin sensitising potency. We have also explored here the possible bases for this modest sensitising activity. Finally, the nature of exposure to LAM has been reviewed briefly and on the basis of that information, together with an understanding of skin sensitising potency, a risk assessment has been prepared. PMID:24956587

  13. Synthesis and characterization of carbon fibers functionalized with poly (glycidyl methacrylate) via atom transfer radical polymerization

    NASA Astrophysics Data System (ADS)

    Wu, Yongwei; Xiong, Lei; Qin, Xiaokang; Wang, Zhengyue; Ding, Bei; Ren, Huan; Pi, Xiaolong

    2015-07-01

    In this work, polyacrylonitrile (PAN)-based carbon fibers (CF) were chemically modified with poly (glycidyl methacrylate) (PGMA) via atom transfer radical polymerization (ATRP) to improve the interaction between the CF and polymer matrix. The FT-IR, TGA, and XPS were used to determine the chemical structure of the resulting products and the quantities of PGMA chains grafted from the CF surface. The experimental results confirm that the CF surface was functionalized and glycidyl methacrylate was graft-polymerized onto the CF, and the grafting content of polymer could reach 10.2%.

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

    SciTech Connect

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

    1985-12-01

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

  15. pH-sensitive methacrylic copolymer gels and the production thereof

    DOEpatents

    Mallapragada, Surya K.; Anderson, Brian C.

    2007-05-15

    The present invention provides novel gel forming methacrylic blocking copolymers that exhibit cationic pH-sensitive behavior as well as good water solubility. The copolymers are constructed by polymerization of a tertiary amine methacrylate with either a (poly(ethylene oxide)-b-poly(propylene oxide)-b-poly(ethylene oxide) polymer, such as the commercially available Pluronic.RTM. polymers, or a poly(ethylene glycol)methyl ether polymer. The polymers may be used for drug and gene delivery, protein separation, as structural supplements, and more.

  16. Reactive Poly(Amic Acid)/ Poly(Glycidyl Methacrylate-r-Poly(ethylene Glycol) Methyl Ether Methacrylate) Blends as Gas Permeation Membranes

    NASA Astrophysics Data System (ADS)

    Beaulieu, Michael; Watkins, James

    2012-02-01

    Polymers containing polar moieties, such as ether groups show an affinity for acidic gases, such as CO2 due to dipole-quadrapole interactions. Polymer blends in which one of the components is poly(ethylene glycol) (PEG) have been studied extensively in literature as a CO2/light gas permeation membrane, but due to the crystallization and poor mechanical properties have been difficult to incorporate PEG above 60wt%. In this study, a series of random copolymers containing both glycidyl methacrylate and poly(ethylene glycol) methyl ether methacrylate in different ratios are blended with a poly(amic acid) prepolymer made from 4, 4'-oxydianiline and pyromellitic dianhydride to create gas permeation membranes. By using a reactive blend PEG loadings above 70% have been realized with sufficient mechanical properties, and since the side chain on the PEGMA is short these blends do not suffer from crystallization.

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

    PubMed

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

    2013-05-01

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

  18. Chest Wall Reconstruction Using a Methyl Methacrylate Neo-Rib and Mesh.

    PubMed

    Suzuki, Kei; Park, Bernard J; Adusumilli, Prasad S; Rizk, Nabil P; Huang, James; Jones, David R; Bains, Manjit S

    2015-08-01

    Prosthetic reconstruction of the chest wall after oncologic resection is performed by means of various techniques using different materials. We describe a new technique of chest wall reconstruction that includes the use of Marlex mesh and the creation of a neo-rib from a Steinmann pin and methyl methacrylate. PMID:26234861

  19. Chest Wall Reconstruction Using a Methyl Methacrylate Neo-rib and Mesh

    PubMed Central

    Suzuki, Kei; Park, Bernard J.; Adusumilli, Prasad S.; Rizk, Nabil P.; Huang, James; Jones, David R.; Bains, Manjit S.

    2016-01-01

    Prosthetic reconstruction of the chest wall after oncologic resection is performed by means of various techniques using different materials. We describe a new technique of chest wall reconstruction that includes the use of Marlex mesh and the creation of a neo-rib from a Steinmann pin and methyl methacrylate. PMID:26234861

  20. Recent Origin of the Methacrylate Redox System in Geobacter sulfurreducens AM-1 through Horizontal Gene Transfer

    PubMed Central

    Arkhipova, Oksana V.; Meer, Margarita V.; Mikoulinskaia, Galina V.; Zakharova, Marina V.; Galushko, Alexander S.; Kondrashov, Fyodor A.

    2015-01-01

    The origin and evolution of novel biochemical functions remains one of the key questions in molecular evolution. We study recently emerged methacrylate reductase function that is thought to have emerged in the last century and reported in Geobacter sulfurreducens strain AM-1. We report the sequence and study the evolution of the operon coding for the flavin-containing methacrylate reductase (Mrd) and tetraheme cytochrome с (Mcc) in the genome of G. sulfurreducens AM-1. Different types of signal peptides in functionally interlinked proteins Mrd and Mcc suggest a possible complex mechanism of biogenesis for chromoproteids of the methacrylate redox system. The homologs of the Mrd and Mcc sequence found in δ-Proteobacteria and Deferribacteres are also organized into an operon and their phylogenetic distribution suggested that these two genes tend to be horizontally transferred together. Specifically, the mrd and mcc genes from G. sulfurreducens AM-1 are not monophyletic with any of the homologs found in other Geobacter genomes. The acquisition of methacrylate reductase function by G. sulfurreducens AM-1 appears linked to a horizontal gene transfer event. However, the new function of the products of mrd and mcc may have evolved either prior or subsequent to their acquisition by G. sulfurreducens AM-1. PMID:25962149

  1. Organometallic nonlinear optical (NLO) polymers. Further development of pendant ferrocene poly(methyl methacrylate) copolymers

    SciTech Connect

    Wright, M.E.; Toplikar, E.G.

    1993-12-31

    The synthesis of several new ferrocene monomers is reported. The copolymerization of these new monomers with methyl methacrylate affords polymers of moderate molecular weights. Synthetic procedures for both monomers and polymers as well as analysis of the properties of the polymers will be presented.

  2. 40 CFR 721.10517 - Alkyl methacrylates, polymer with substituted carbomonocycle, hydroxymethyl acrylamide and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Alkyl methacrylates, polymer with substituted carbomonocycle, hydroxymethyl acrylamide and fluorinatedalkyl acrylate (generic). 721.10517 Section 721.10517 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES CONTROL ACT SIGNIFICANT NEW USES OF...

  3. Enthalpy of mixing of methacrylic acid with organic solvents at 293 K

    NASA Astrophysics Data System (ADS)

    Sergeev, V. V.

    2016-03-01

    The enthalpies of mixing of binary systems of methacrylic acid with acetonitrile, benzene, hexane, 1,2-dichloroethane, and acetic acid are measured calorimetrically at 293 K and atmospheric pressure. The enthalpy of mixing of all the studied binary systems is positive over the range of concentrations.

  4. 78 FR 55644 - Styrene, Copolymers with Acrylic Acid and/or Methacrylic Acid; Tolerance Exemption

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-11

    ... number average molecular weight (in amu), 1,200 when used as an inert ingredient in a pesticide chemical... Register of July 19, 2013 (78 FR 43118) (FRL-9392- 9), EPA issued a notice pursuant to section 408 of FFDCA... number average molecular weight (in amu), 1,200 to include the monomer lauryl methacrylate. That...

  5. RAFT "grafting-through" approach to surface-anchored polymers: Electrodeposition of an electroactive methacrylate monomer.

    PubMed

    Grande, C D; Tria, M C; Felipe, M J; Zuluaga, F; Advincula, R

    2011-02-01

    The synthesis of homopolymer and diblock copolymers on surfaces was demonstrated using electrodeposition of a methacrylate-functionalized carbazole dendron and subsequent reversible addition-fragmentation chain transfer (RAFT) "grafting-through" polymerization. First, the anodically electroactive carbazole dendron with methacrylate moiety (G1CzMA) was electrodeposited over a conducting surface (i.e. gold or indium tin oxide (ITO)) using cyclic voltammetry (CV). The electrodeposition process formed a crosslinked layer of carbazole units bearing exposed methacrylate moieties. This film was then used as the surface for RAFT polymerization process of methyl methacrylate (MMA), styrene (S), and tert-butyl acrylate (TBA) in the presence of a free RAFT agent and a free radical initiator, resulting in grafted polymer chains. The molecular weights and the polydispersity indices (PDI) of the sacrificial polymers were determined by gel permeation chromatography (GPC). The stages of surface modification were investigated using X-ray photoelectron spectroscopy (XPS), ellipsometry, and atomic force microscopy (AFM) to confirm the surface composition, thickness, and film morphology, respectively. UV-Vis spectroscopy also confirmed the formation of an electro-optically active crosslinked carbazole film with a [Formula: see text] - [Formula: see text] absorption band from 450-650nm. Static water contact angle measurements confirmed the changes in surface energy of the ultrathin films with each modification step. The controlled polymer growth from the conducting polymer-modified surface suggests the viability of combining electrodeposition and grafting-through approach to form functional polymer ultrathin films.

  6. Copolymer of methacrylic acid with its diethylammonium salt: Effective waterproofing agent for oil wells

    SciTech Connect

    Kuznetsova, O.N.; Avvakumova, N.I.

    1992-08-10

    In the development of technology for the copolymerization of methacrylic acid with its diethylammonium salt (MAA-MAA{center_dot}DEA), the polymer-like reaction of polymethacrylic acid (PMAA) with diethylamine (DEA) and the polymerization of MAA in the presence of DEA have been studied. 13 refs., 3 figs., 4 tabs.

  7. Crack resistance of polycarbonate and polymethyl methacrylate at high loading rates

    SciTech Connect

    Eremenko, A.S.; Girin, A.S.; Novikov, S.A.; Sinitsyn, V.A.

    1986-01-01

    The authors study the temperature and rate relationships of crack resistance of polymers. Disk specimens of polymethyl methacrylate and type PK-1 polycarbonate were tested at 20 + or - 1 C and -15 + or - 1 C. It was established that in the initial portion the crack propagates at an almost constant rate.

  8. Exposure to airborne methacrylates and natural rubber latex allergens in dental clinics.

    PubMed

    Henriks-Eckerman, M L; Alanko, K; Jolanki, R; Kerosuo, H; Kanerva, L

    2001-06-01

    The exposure of dental personnel to airborne methacrylates and natural rubber latex (NRL) allergens was studied during placing of composite resin restorations in six dental clinics in Finland. Both area and personal sampling were performed, and special attention was paid to measurement of short-term emissions from the patient's mouth. Methacrylates were collected onto thermal desorption tubes filled with Tenax TA and NRL allergens onto membrane filters. The methacrylate samples were thermally desorbed and analysed by gas chromatography with mass selective detection. The NRL allergen concentrations were determined by the allergen-specific IgE-ELISA-inhibition method. The median concentration of 2-hydroxyethylmethacrylate (2-HEMA) was 0.004 mg m-3 close to the dental nurse's work-desk and 0.003 mg m-3 in the breathing zone of the nurse with a maximum concentration of 0.033 mg m-3. Above the patient's mouth the concentration of 2-HEMA was about 0.01 mg m-3 during both working stages, i.e., during application of adhesive and composite resins and during finishing and polishing of the fillings. Maximum concentrations of 3-5 times higher than median concentrations were also measured. Triethyleneglycol dimethacrylate was released into the air mainly during the removal of old composite resin restorations (0.05 mg m-3) and only to a minor extent during finishing and polishing procedures. The median concentration of the NRL allergen was 0.12 au m-3 (au = arbitrary unit) with a maximum concentration of 1.1 au m-3. The results show that, except for short-term emissions from the patient's mouth, the exposure of dental personnel to methacrylates and NRL allergens is very low. Measures to reduce exposure are discussed, as the airborne concentrations of methacrylates should be kept as low as possible in order to reduce the risk of hypersensitivity.

  9. Synthesis of [.sup.13C] and [.sup.2H] substituted methacrylic acid, [.sup.13C] and [.sup.2H] substituted methyl methacrylate and/or related compounds

    DOEpatents

    Alvarez, Marc A.; Martinez, Rodolfo A.; Unkefer, Clifford J.

    2008-01-22

    The present invention is directed to labeled compounds of the formulae ##STR00001## wherein Q is selected from the group consisting of --S--, --S(.dbd.O)--, and --S(.dbd.O).sub.2--, Z is selected from the group consisting of 1-naphthyl, substituted 1-naphthyl, 2-naphthyl, substituted 2-naphthyl, and phenyl groups with the structure ##STR00002## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are each independently selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl, a halogen, and an amino group selected from the group consisting of NH.sub.2, NHR and NRR' where R and R' are each independently selected from the group consisting of a C.sub.1-C.sub.4 lower alkyl, an aryl, and an alkoxy group, and X is selected from the group consisting of hydrogen, a C.sub.1-C.sub.4 lower alkyl group, and a fully-deuterated C.sub.1-C.sub.4 lower alkyl group. The present invention is also directed to a process of preparing labeled compounds, e.g., process of preparing [.sup.13C]methacrylic acid by reacting a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13CH.sub.2)-- aryl sulfone precursor with .sup.13CHI to form a (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate, and, reacting the (CH.sub.3CH.sub.2O--.sup.13C(O)--.sup.13C(.sup.13CH.sub.3).sub.2)-- aryl sulfone intermediate with sodium hydroxide, followed by acid to form [.sup.13C]methacrylic acid. The present invention is further directed to a process of preparing [.sup.2H.sub.8]methyl methacrylate by reacting a (HOOC--C(C.sup.2H.sub.3).sub.2-- aryl sulfinyl intermediate with CD.sub.3I to form a (.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate, and heating the(.sup.2H.sub.3COOC--C(C.sup.2H.sub.3).sub.2)-- aryl sulfinyl intermediate at temperatures and for time sufficient to form [.sup.2H.sub.8]methyl methacrylate.

  10. Process for producing a well-adhered durable optical coating on an optical plastic substrate. [abrasion resistant polymethyl methacrylate lenses

    NASA Technical Reports Server (NTRS)

    Kubacki, R. M. (Inventor)

    1978-01-01

    A low temperature plasma polymerization process is described for applying an optical plastic substrate, such as a polymethyl methacrylate lens, with a single layer abrasive resistant coating to improve the durability of the plastic.

  11. ATOM TRANSFER RADICAL POLYMERIZATION OF N-BUTYL METHACRYLATE IN AQUEOUS DISPERSED SYSTEMS: A MINIEMULSION APPROACH. (R826735)

    EPA Science Inventory

    Ultrasonication was applied in combination with a hydrophobe for the copper-mediated atom transfer radical polymerization of n-butyl methacrylate in an aqueous dispersed system. A controlled polymerization was successfully achieved, as demonstrated by a linear correlation between...

  12. Effect of epoxidation on 30% poly(methyl methacrylate)-grafted natural rubber polymer electrolytes

    SciTech Connect

    Nazir, Khuzaimah; Aziz, Ahmad Fairoz; Adam, Nurul Ilham; Yahya, Muhd Zu Azhan; Ali, Ab Malik Marwan

    2015-08-28

    Epoxidized 30% poly(methyl methacrylate)-grafted natural rubber (EMG 30) as a polymer host in solid polymer electrolytes (SPEs) has been investigated. EMG30 was synthesized via performicepoxidation method onto 30% poly(methyl methacrylate)-grafted natural rubber (MG30) and the formations of epoxy group were discussed. The EMG30 were characterized by proton nuclear magnetic resonance ({sup 1}HNMR) to investigate their chemical structure and differential scanning calorimeter to determine their crystallinity. A new peak in {sup 1}HNMR spectra (2.71 ppm) confirmed the appearance of epoxy group. SPE based on EMG30 doped with 40 wt% LiCF{sub 3}SO{sub 3} show the highest conductivity. The complexation between EMG30 and LiCF{sub 3}SO{sub 3} were confirmed by attenuated total reflection Fourier transform infrared (ATR-FTIR)

  13. Separation of heavy metals from water by functionalized glycidyl methacrylate poly (high internal phase emulsions).

    PubMed

    Huš, Sebastjan; Kolar, Mitja; Krajnc, Peter

    2016-03-11

    Removal of silver, lead and cadmium ions from both model solutions and real contaminated water was achieved, in a flow through manner, by using highly porous functionalized poly(glycidyl methacrylate) materials, prepared by the polymerisation of high internal phase emulsions (polyHIPE), with significant sorption differences between metals allowing for selective removal. PolyHIPEs, initially prepared from glycidyl methacrylate as a functional monomer, were functionalized with pentaerythritol tetrakis(3-mercaptopropionate), 1,9-nonanedithiol and 2-aminobenzenethiol via the epoxy ring opening on the polymer supports and applied in a flow-through manner via encasements into dedicated disk holders. Capacity of 21.7mg Ag per gram of polymer was found for 1,9-nonanedithiol functionalized polymers, while the capacity was decreasing with the decreasing ionic radius of the metal; the dynamics of sorption also depended on metal ion size and furthermore on the thiol used for the polymer functionalization.

  14. Preparation of monodisperse porous silica particles using poly(glycidyl methacrylate) microspheres as a template.

    PubMed

    Grama, S; Horák, D

    2015-01-01

    Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres were used as a template for preparing porous silica particles. The starting polymer microspheres that were 9.3 microm in size were synthesized by multistep swelling polymerization using a modified Ugelstad technique. Subsequently, silica (SiO2) was deposited on the surface and inside the PGMA microspheres to produce poly(glycidyl methacrylate)-silica hybrid particles (PGMA-SiO2). Upon calcination of the PGMA-SiO2 microspheres, porous silica particles were formed. The morphology, particle size, polydispersity and inner structure of the silica microspheres were investigated by scanning and transmission electron microscopy. Thermogravimetric analysis and dynamic adsorption of nitrogen determined the amount of silica formed and its specific surface area. Compared with the starting PGMA microspheres, the size of the porous silica particles decreased by up to 30%. These porous silica microspheres are promising for chromatography and biomedical applications. PMID:26447591

  15. Experimental and theoretical investigation of the complexation of methacrylic acid and diisopropyl urea.

    PubMed

    Pogány, Peter; Razali, Mayamin; Szekely, Gyorgy

    2017-01-01

    The present paper explores the complexation ability of methacrylic acid which is one of the most abundant functional monomer for the preparation of molecularly imprinted polymers. Host-guest interactions and the mechanism of complex formation between methacrylic acid and potentially genotoxic 1,3-diisopropylurea were investigated in the pre-polymerization solution featuring both experimental (NMR, IR) and in silico density functional theory (DFT) tools. The continuous variation method revealed the presence of higher-order complexes and the appearance of self-association which were both taken into account during the determination of the association constants. The quantum chemical calculations - performed at B3LYP 6-311++G(d,p) level with basis set superposition error (BSSE) corrections - are in agreement with the experimental observations, reaffirming the association constants and justifying the validity of computational investigation of such systems. Furthermore, natural bond orbital analysis was carried out to appraise the binding properties of the complexes.

  16. Unbiased phosphoproteomic method identifies the initial effects of a methacrylic acid copolymer on macrophages.

    PubMed

    Chamberlain, Michael Dean; Wells, Laura A; Lisovsky, Alexandra; Guo, Hongbo; Isserlin, Ruth; Talior-Volodarsky, Ilana; Mahou, Redouan; Emili, Andrew; Sefton, Michael V

    2015-08-25

    An unbiased phosphoproteomic method was used to identify biomaterial-associated changes in the phosphorylation patterns of macrophage-like cells. The phosphorylation differences between differentiated THP1 (dTHP1) cells treated for 10, 20, or 30 min with a vascular regenerative methacrylic acid (MAA) copolymer or a control methyl methacrylate (MM) copolymer were determined by MS. There were 1,470 peptides (corresponding to 729 proteins) that were differentially phosphorylated in dTHP1 cells treated with the two materials with a greater cellular response to MAA treatment. In addition to identifying pathways (such as integrin signaling and cytoskeletal arrangement) that are well known to change with cell-material interaction, previously unidentified pathways, such as apoptosis and mRNA splicing, were also discovered. PMID:26261332

  17. Amphiphilic Copolymers of Polyfluorene Methacrylates Exhibiting Tunable Emissions for Ink-Jet Printing.

    PubMed

    Deng, Chao; Ling, Jun

    2016-08-01

    Functionalized polyfluorene receives more and more attention due to its wide applications. Here, the syntheses of three novel polyfluorene-based methacrylate macromonomers exhibiting a vast flexibility for further applications are reported. Their emissions strongly depend on the end groups and thus the macromonomers provide blue, green, and red emissions simultaneously with the same excitation light of 365 nm. Their well-defined copolymers with 2-(dimethylamino) ethyl methacrylate via reversible addition-fragmentation chain transfer polymerization are investigated in detail. These copolymers exhibit high quantum yields in solid film (up to 0.8), and self-assemble into photoluminescent nanoparticles in aqueous solutions with pure blue, green, and red emissions. By simply mixing them, perfect white light emission with high quality is obtained. These aqueous nanoparticles solutions are ready for ink-jet printing to produce exquisite bright and colorful fluorescent pictures. PMID:27310485

  18. Experimental and theoretical investigation of the complexation of methacrylic acid and diisopropyl urea.

    PubMed

    Pogány, Peter; Razali, Mayamin; Szekely, Gyorgy

    2017-01-01

    The present paper explores the complexation ability of methacrylic acid which is one of the most abundant functional monomer for the preparation of molecularly imprinted polymers. Host-guest interactions and the mechanism of complex formation between methacrylic acid and potentially genotoxic 1,3-diisopropylurea were investigated in the pre-polymerization solution featuring both experimental (NMR, IR) and in silico density functional theory (DFT) tools. The continuous variation method revealed the presence of higher-order complexes and the appearance of self-association which were both taken into account during the determination of the association constants. The quantum chemical calculations - performed at B3LYP 6-311++G(d,p) level with basis set superposition error (BSSE) corrections - are in agreement with the experimental observations, reaffirming the association constants and justifying the validity of computational investigation of such systems. Furthermore, natural bond orbital analysis was carried out to appraise the binding properties of the complexes. PMID:27419640

  19. Preparation of monodisperse porous silica particles using poly(glycidyl methacrylate) microspheres as a template.

    PubMed

    Grama, S; Horák, D

    2015-01-01

    Monodisperse macroporous poly(glycidyl methacrylate) (PGMA) microspheres were used as a template for preparing porous silica particles. The starting polymer microspheres that were 9.3 microm in size were synthesized by multistep swelling polymerization using a modified Ugelstad technique. Subsequently, silica (SiO2) was deposited on the surface and inside the PGMA microspheres to produce poly(glycidyl methacrylate)-silica hybrid particles (PGMA-SiO2). Upon calcination of the PGMA-SiO2 microspheres, porous silica particles were formed. The morphology, particle size, polydispersity and inner structure of the silica microspheres were investigated by scanning and transmission electron microscopy. Thermogravimetric analysis and dynamic adsorption of nitrogen determined the amount of silica formed and its specific surface area. Compared with the starting PGMA microspheres, the size of the porous silica particles decreased by up to 30%. These porous silica microspheres are promising for chromatography and biomedical applications.

  20. Grafting of Chitosan and Chitosantrimethoxylsilylpropyl Methacrylate on Single Walled Carbon Nanotubes-Synthesis and Characterization

    PubMed Central

    Carson, Laura; Kelly-Brown, Cordella; Stewart, Melisa; Oki, Aderemi; Regisford, Gloria; Stone, Julia; Traisawatwong, Pasakorn; Durand-Rougely, Clarissa; Luo, Zhiping

    2011-01-01

    Acid functionalized single walled carbon nanotubes (CNTs) were grafted to chitosan by first reacting the oxidized CNTs with thionyl chloride to form acyl-chlorinated CNTs. This product was subsequently dispersed in chitosan and covalently grafted to form CNT-chitosan. CNT-chitosan was further grafted onto 3-trimethoxysilylpropyl methacrylate by free radical polymerization conditions, to yield CNT-g-chitosan-g-3-trimethoxysilylpropyl methacrylate (TMSPM), hereafter referred to as CNT-chitosan-3-TMSPM. These composites were characterized by Fourier Transform Infrared Resonance Spectroscopy (FTIR), carbon-13 nuclear magnetic resonance (13C NMR), Thermogravimetric Analysis (TGA), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The composite showed improved thermal stability and could be of great potential use in bone tissue engineering. PMID:21765959

  1. Surface-initiated Polymerization of Azidopropyl Methacrylate and its Film Elaboration via Click Chemistry

    PubMed Central

    Saha, Sampa; Bruening, Merlin L.; Baker, Gregory L.

    2013-01-01

    Azidopropyl methacrylate (AzPMA), a functional monomer with a pendent azido group, polymerizes from surfaces and provides polymer brushes amenable to subsequent elaboration via click chemistry. In DMF at 50 °C, click reactions between poly(AzPMA) brushes and an alkynylated dye proceed with >90% conversion in a few minutes. However, in aqueous solutions, reaction with an alkyne-containing poly(ethylene glycol) methyl ether (mPEG, Mn=5000) gives <10% conversion after a 12-h reaction at room temperature. Formation of copolymers with AzPMA and polyethylene glycol methyl ether methacrylate (mPEGMA) enables control over the hydrophilicity and functional group density in the copolymer to increase the yield of aqueous click reactions. The copolymers show reaction efficiencies as high as 60%. These studies suggest that for aqueous applications such as bioconjugation via click chemistry, control over brush hydrophilicity is vital. PMID:24293702

  2. Quaternary ammonium silane-functionalized, methacrylate resin composition with antimicrobial activities and self-repair potential

    PubMed Central

    Gong, Shi-qiang; Niu, Li-na; Kemp, Lisa K.; Yiu, Cynthia K.Y.; Ryou, Heonjune; Qi, Yi-pin; Blizzard, John D.; Nikonov, Sergey; Brackett, Martha G.; Messer, Regina L.W.; Wu, Christine D.; Mao, Jing; Brister, L. Bryan; Rueggeberg, Frederick A.; Arola, Dwayne D.; Pashley, David H.; Tay, Franklin R.

    2012-01-01

    Design of antimicrobial polymers for enhancing healthcare issues and minimizing environmental problems is an important endeavor with both fundamental and practical implications. Quaternary ammonium silane-functionalized methacrylate (QAMS) represents an example of antimicrobial macromonomers synthesized by a sol-gel chemical route; these compounds possess flexible Si-O-Si bonds. In present work, a partially-hydrolyzed QAMS copolymerized with bis-GMA is introduced. This methacrylate resin was shown to possess desirable mechanical properties with both a high degree of conversion and minimal polymerization shrinkage. Kill-on-contact microbiocidal activities of this resin were demonstrated using single-species biofilms of Streptococcus mutans (ATCC 36558), Actinomyces naeslundii (ATCC 12104) and Candida albicans (ATCC 90028). Improved mechanical properties after hydration provided the proof-of-concept that QAMS-incorporated resin exhibits self-repair potential via water-induced condensation of organic modified silicate (ormosil) phases within the polymerized resin matrix. PMID:22659173

  3. Synthesis and characterization of hydrolysed starch-g-poly(methacrylic acid) composite.

    PubMed

    Zahran, Magdy K; Ahmed, Enas M; El-Rafie, Mohamed H

    2016-06-01

    A novel method for the synthesis of starch-g-poly(methacrylic acid) composite was adopted by graft polymerization of hydrolysed starch (HS) and methacrylic acid (MAA) in aqueous medium using an efficient sodium perborate (SPB)-thiourea (TU) redox initiation system. The parameters influencing the redox system efficiency and thence the polymerization method were considered. These parameters comprehended the concentrations of MAA, SPB, TU and SPB/TU molar ratio as well as the polymerization temperature. The polymerization reaction was scrutinized through calculation of the MAA total conversion percent (TC%). The resultant poly(MAA-HS) composite was assessed by evaluating the polymer criteria (the graft yield, GY%; the grafting efficiency, GE%; the homopolymer, HP%; and the total conversion). The comportment of the apparent viscosity of the cooked poly(MAA)-starch composite paste, obtained under diverse polymerization conditions, was examined. Tentative mechanisms, which depict all occasions that happen amid the entire course of the polymerization reaction, have been proffered. PMID:26968925

  4. Atom transfer radical polymerization to fabricate monodisperse poly[glycidyl methacrylate-co-poly (ethylene glycol) methacrylate] microspheres and its application for protein affinity purification.

    PubMed

    Yu, Ling; Shi, Zhuan Zhuan; Li, Chang Ming

    2015-09-01

    Poly[glycidyl methacrylate-co-poly (ethylene glycol) methacrylate] microspheres for the first time were successfully synthesized by atom transfer radical polymerization (ATRP) method at room temperature. The co-polymerization approach was investigated to delicately control the microsphere morphology and size-distribution by reaction conditions including solvent percentage, monomer loading and rotation speed. The results show that the average size of the microspheres is ∼5.7 μm with coexistence of epoxy, hydroxyl and ether groups, which provide plentiful functional sites for protein anchoring. The mechanism of the microsphere formation is proposed. The microsphere successfully demonstrates its unique application for affinity purification of proteins, in which the functional epoxy group facilitates a simple and efficient protein covalent immobilization to purify immunoglobulin G on the microspheres, while the hydrophilic poly (ethylene glycol) motif can repulse nonspecific protein adsorption for good specificity. This microspheres can be used in broad protein biosensors due to their abundant functional groups and high surface to volume ratio.

  5. Study of the water structure in poly(methyl methacrylate-block-2-hydroxyethyl methacrylate) and its relationship to platelet adhesion on the copolymer surface.

    PubMed

    Mochizuki, Akira; Namiki, Takahiro; Nishimori, Yusuke; Ogawa, Haruki

    2015-01-01

    The water structure and platelet compatibility of poly(methyl methacrylate (MMA)-block-2-hydroxyethyl methacrylate (HEMA)) were investigated. The molecular weight (Mn) of the polyHEMA segment was kept constant (average: 9600), while the Mn of the polyMMA segment was varied from 1340 to 7390. The equilibrium water content of the copolymers was found to be mainly governed by the HEMA content. The water structure in the copolymers was characterized in terms of the amounts of non-freezing and freezing water (abbreviated as Wnf and Wfz, respectively) using differential scanning calorimetry. It was found that the Wnf for the copolymers were higher than those estimated from the Wnf for the HEMA and MMA homopolymers and that the amount of excess non-freezing water depended on the polyMMA segment length. In addition, X-ray diffraction analysis revealed that some of the copolymers had cold-crystallizable water. These facts suggested that the polyMMA segments were involved in determining the water structures in the copolymers. Furthermore, the platelet compatibility of the copolymers was improved as compared to that of the HEMA homopolymer. It was therefore concluded that the platelet compatibility of the copolymer was related to the amount of excess non-freezing water.

  6. Fabrication of Poly(methyl Methacrylate) microfluidic chips by redox-initiated polymerization

    SciTech Connect

    Chen, Jiang; Lin, Yuehe; Chen, Gang

    2007-08-16

    In this report, a method based on the redox-initiated polymerization of methyl methacrylate (MMA) has been developed for the rapid fabrication of PMMA microfluidic chips.The new fabrication approach obviates the need for special equipment and significantly simplifies the process of fabricating microdevices. The attractive performance of the novel PMMA microchips has been demonstrated in connection with contactless conductivity detection for the separation and detection of ionic species.

  7. Carboxybetaine methacrylate polymers offer robust, long-term protection against cell adhesion

    PubMed Central

    Mahmud, Goher; Huda, Sabil; Yang, Wei; Kandere-Grzybowska, Kristiana; Pilans, Didzis; Jiang, Shaoyi; Grzybowski, Bartosz A.

    2013-01-01

    Films of poly(carboxybetaine methacrylate), poly(CBMA), grafted onto microetched gold slides are effective in preventing non-specific adhesion of cells of different types. The degree of adhesion resistance is comparable to that achieved with the self-assembled monolayers, SAMs, of oligo(ethylene glycol) alkanethiolates. In sharp contrast to the SAMs, however, substrates protected with poly(CBMA) can be stored in dry state without losing their protective properties for periods up to two weeks. PMID:21711048

  8. Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Technology (Revised) (Presentation)

    SciTech Connect

    Miller, D. C.; Carloni, J. D.; Pankow, J. W.; Gjersing, E. L.; To, B.; Packard, C. E.; Kennedy, C. E.; Kurtz, S. R.

    2012-01-01

    Concentrating photovoltaic (CPV) technology recently gained interest based on its expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems employ Fresnel lenses composed of poly(methyl methacrylate) (PMMA) to obtain a high optical flux density on the cell. The optical and mechanical durability of these lenses, however, is not well established relative to the desired surface life of 30 years. Our research aims to quantify the expected lifetime of PMMA in key market locations (FL, AZ, and CO).

  9. Radiation-grafting of ethylene glycol dimethacrylate (EGDMA) and glycidyl methacrylate (GMA) onto silicone rubber

    NASA Astrophysics Data System (ADS)

    Flores-Rojas, G. G.; Bucio, E.

    2016-10-01

    Silicone rubber (SR) was modified with a graft of ethylene glycol dimethacrylate (EGDMA) and glycidyl methacrylate (GMA) using either gamma-radiation or azobisisobutyronitrile (AIBN). The graft efficiency was evaluated as a function of monomer concentration, absorbed dose, reaction temperature, and concentration of AIBN. The hydrophilicity of the grafted films was measured by contact angle and their equilibrium swelling time in ethanol. Additional characterization by infrared (FTIR-ATR) spectroscopy, thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) is also reported.

  10. Reactive aluminum metal nanoparticles within a photodegradable poly(methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    Patel, Ashish; Becic, Jasmin; Buckner, Steven W.; Jelliss, Paul A.

    2014-01-01

    We report here on new photoreactive core-matrix reactive metal nanoparticles. Poly(methyl methacrylate)-capped aluminum nanoparticles (PMMA-Al NPs) were synthesized and demonstrated air stability on the order of 2 months. Upon exposure of the PMMA-Al NPs to UV radiation the composite reacts more rapidly to release H2 gas from alkaline solution. FTIR spectroscopy indicates that the PMMA cap degrades under UV irradiation, exposing the reactive metal core.

  11. Polypropylene fumarate/phloroglucinol triglycidyl methacrylate blend for use as partially biodegradable orthopaedic cement.

    PubMed

    Jayabalan, M; Thomas, V; Rajesh, P N

    2001-10-01

    Polypropylene fumarate/phloroglucinol triglycidyl methacrylate oligomeric blend-based bone cement was studied. Higher the percentage of phloroglucinol triglycidyl methacrylate, lesser the setting time. An optimum setting time could be arrived with 50:50 blend composition of the two oligomers. Composite cement of 50:50 blend prepared with hydroxyapatite granules of particle size 125 microm binds bovine rib bones. The tensile strength of this adhesive bond was found to be 1.11 kPa. The thermal studies suggest the onset of cross-linking reaction in the cured blend if the blend is heated. The absence of softening endotherm in the cured blend shows the thermosetting-like amorphous nature of blend system, which may restrict the changes in creep properties. The in vitro biodegradation studies reveal possible association of calcium ions with negatively charged units of degrading polymer chain resulting in slow down of degradation. Relatively slow degradation was observed in Ringer's solution. The study reveals the potential use of polypropylene fumarate/phloroglucinol triglycidyl methacrylate as partially degradable polymeric cement for orthopaedic applications. PMID:11545309

  12. Synthesis, Characterization, and In Vitro Evaluation of New Ibuprofen Polymeric Prodrugs Based on 2-Hydroxypropyl Methacrylate

    PubMed Central

    Babazadeh, Mirzaagha; Sheidaei, Maryam; Abbaspour, Sara; Edjlali, Ladan

    2013-01-01

    The present research work describes the synthesis and evaluation of new acrylic-type polymeric systems having degradable ester bonds linked to ibuprofen as materials for drug delivery. Ibuprofen was linked to 2-hydroxy-propyl methacrylate by an activated ester methodology in a one-pot procedure with a high yield. The resulting material was copolymerized with either 2-hydroxyethyl methacrylate or methyl methacrylate (in 1:3 mole ratios) by the free radical polymerization method, utilizing azoisobutyronitrile at 65–70 °C. The characterization of the resulting products by FTIR, 1H NMR, 13C NMR, DSC, and elemental analysis confirmed their synthesis successfully. Ibuprofen release from the obtained polymers was preliminarily evaluated at different buffered solutions (pH 1, 7.4, and 10) into dialysis bags to show the capacity of prodrugs to release the drug under hydrolytic conditions. Detection of hydrolysis by UV spectroscopy at selected intervals showed that the drug can be released by selective hydrolysis of the ester bond at the side of the drug moiety. The release profiles indicated that the hydrolytic behavior of polymers is strongly based on the polymer hydrophilicity and the pH value of the hydrolysis solution. The results suggest that these polymers could be useful in controlled release systems. PMID:23641345

  13. Mechanical Properties of Individual Composite Poly(methyl-methacrylate) -Multiwalled Carbon Nanotubes Nanofibers

    NASA Astrophysics Data System (ADS)

    Grabbert, Niels; Wang, Bei; Avnon, Asaf; Zhuo, Shuyao; Datsyuk, Vitaliy; Trotsenko, Svitlana; Mackowiak, Piotr; Kaletta, Katrin; Lang, Klaus-Dieter; Ngo, Ha-Duong

    2014-08-01

    Multiwalled carbon nanotubes with their superb mechanical properties are an unique filler material for polymer composites. Here, we present an investigation of mechanical properties of electrospun Poly-(methyl-methacrylate) multiwalled carbon nanotubes composite nanofibers. The method of electrospinning was used to fabricate suspended individual Poly-(methyl-methacrylate) multiwalled carbon nanotubes nanofibers. In order to reinforce the nanofibers, different high concentration of multiwalled carbon nanotubes were used. Transmission electron microscopy measurements reveal a successful filling of the nanofibers. The different types of nanofibers were deposited at SiO2 substrates. Which were previously etched, to create trenches for bend tests. Followed by fixing the nanofiber with a focus ion beam platinum deposition at the trench edges. An atomic force microscopy was used to perform the mechanical nanofiber bending tests over trenches. The results were compared with pristine Poly-(methyl- methacrylate) nanofibers to nanofibers with 15 weight% and 20 weight% multiwalled carbon nanotubes composite fibers. We observed that pristine nanofibers have Young's modulus of 136 MPa, while for composite nanofibers with 15 weight% have 2.65 GPa and with 20 weight% have 6.06 GPa (at room temperature and air ambiance). This corresponds to an increase of Young's modulus of 19 fold between the pristine nanofibers and the 15 weight% of mutliwalled carbon nanotubes filled nanofibers. Therefore the increase of the Young's modulus compared between the pristine and the 20 weight% MWCNT filled nanofibers corresponds to 45 fold.

  14. Cell-laden microengineered pullulan methacrylate hydrogels promote cell proliferation and 3D cluster formation.

    PubMed

    Bae, Hojae; Ahari, Amir F; Shin, Hyeongho; Nichol, Jason W; Hutson, Che B; Masaeli, Mahdokht; Kim, Su-Hwan; Aubin, Hug; Yamanlar, Seda; Khademhosseini, Ali

    2011-01-01

    The ability to encapsulate cells in three-dimensional (3D) environments is potentially of benefit for tissue engineering and regenerative medicine. In this paper, we introduce pullulan methacrylate (PulMA) as a promising hydrogel platform for creating cell-laden microscale tissues. The hydration and mechanical properties of PulMA were demonstrated to be tunable through modulation of the degree of methacrylation and gel concentration. Cells encapsulated in PulMA exhibited excellent viability. Interestingly, while cells did not elongate in PulMA hydrogels, cells proliferated and organized into clusters, the size of which could be controlled by the hydrogel composition. By mixing with gelatin methacrylate (GelMA), the biological properties of PulMA could be enhanced as demonstrated by cells readily attaching to, proliferating, and elongating within the PulMA/GelMA composite hydrogels. These data suggest that PulMA hydrogels could be useful for creating complex, cell-responsive microtissues, especially for applications that require controlled cell clustering and proliferation.

  15. Rapid determination of sterols in vegetable oils by CEC using methacrylate ester-based monolithic columns.

    PubMed

    Lerma-García, María Jesús; Simó-Alfonso, Ernesto F; Ramis-Ramos, Guillermo; Herrero-Martínez, José M

    2008-11-01

    A method for the determination of sterols in vegetable oils by CEC with UV-Vis detection, using methacrylate ester-based monolithic columns, has been developed. To prepare the columns, polymerization mixtures containing monomers of different hydrophobicities were tried. The influence of composition of polymerization mixture was optimized in terms of porogenic solvent, monomers/porogens and monomer/crosslinker ratios. The composition of the mobile phase was also studied. The optimum monolith was obtained with lauryl methacrylate monomer at 60:40% (wt:wt) lauryl methacrylate/ethylene dimethacrylate ratio and 60 wt% porogens with 20 wt% of 1,4-butanediol (12 wt% 1,4-butanediol in the polymerization mixture). Excellent resolution between sterols was achieved in less than 7 min with an 85:10:5 v/v/v ACN-2-propanol-water buffer containing 5 mM Tris at pH 8.0. The limits of detection were lower than 0.04 mM, and inter-day and column-to-column reproducibilities at 0.75 mM were better than 6.2%. The method was applied to the determination of sterols in vegetable oils with different botanical origins and to detect olive oil adulteration with sunflower and soybean oils.

  16. Study of sodium dodecyl sulfate-poly(propylene oxide) methacrylate mixed micelles.

    PubMed

    Bastiat, Guillaume; Grassl, Bruno; Khoukh, Abdel; François, Jeanne

    2004-07-01

    Sodium dodecyl sulfate (SDS)-poly(propylene oxide) methacrylate (PPOMA) (of molecular weight M(w) = 434 g x mol(-1)) mixtures have been studied using conductimetry, static light scattering, fluorescence spectroscopy, and 1H NMR. It has been shown that SDS and PPOMA form mixed micelles, and SDS and PPOMA aggregation numbers, N(ag SDS) and N(ag PPOMA), have been determined. Total aggregation numbers of the micelles (N(ag SDS) + N(ag PPOMA)) and those of SDS decrease upon increasing the weight ratio R = PPOMA/SDS. Localization of PPOMA inside the mixed micelles is considered (i) using 1H NMR to localize the methacrylate function at the hydrophobic core-water interface and (ii) by studying the SDS-PPO micellar system (whose M(w) = 400 g x mol(-1)). Both methods have indicated that the PPO chain of the macromonomer is localized at the SDS micelle surface. Models based on the theorical prediction of the critical micellar concentration of mixed micelles and structural model of swollen micelles are used to confirm the particular structure proposed for the SDS-PPOMA system, i.e., the micelle hydrophobic core is primarily composed of the C12 chains of the sodium dodecyl sulfate, the hydrophobic core-water interface is made up of the SDS polar heads as well as methacrylate functions of the PPOMA, the PPO chains of the macromonomer are adsorbed preferentially on the surface, i.e., on the polar heads of the SDS.

  17. CEC column behaviour of butyl and lauryl methacrylate monoliths prepared in non-aqueous media.

    PubMed

    Cantó-Mirapeix, Amparo; Herrero-Martínez, José M; Mongay-Fernández, Carlos; Simó-Alfonso, Ernesto F

    2009-02-01

    Polymeric monolithic stationary phases for capillary electrochromatography were prepared using two bulk monomers, butyl methacrylate (BMA) and lauryl methacrylate (LMA), by in situ polymerization in non-aqueous media. The effect of 1,4-butanediol/1-propanol ratio on porous properties was investigated separately for each monomer, keeping the proportion of monomers to pore-forming solvents fixed at 40:60 wt:wt. Also, mixtures of BMA and LMA at different 1,4-butanediol/1-propanol ratios were studied for tailoring the morphological features of the monolithic columns. The chromatographic performance of the different columns was evaluated by means of van Deemter plots of polycyclic aromatic hydrocarbons. Mercury-intrusion porosimetry, SEM, and nitrogen-adsorption measurements were also performed in order to understand their retention behaviour and porous properties. A comparison of these features was also performed for monoliths made with one bulk monomer (BMA or LMA) and with mixtures of both. These mixed monoliths showed satisfactory efficiencies and analysis times compared with those made with one bulk monomer; thus, the BMA-LMA monoliths constitute an attractive alternative to manipulate the electrochromatographic properties of methacrylate beds in CEC. PMID:19170053

  18. Reactive electrospinning and biodegradation of cross-linked methacrylated polycarbonate nanofibers.

    PubMed

    Wu, Ruizhi; Zhang, Jian-Feng; Fan, Yuwei; Stoute, Diana; Lallier, Thomas; Xu, Xiaoming

    2011-06-01

    The objectives of this study were to fabricate cross-linked biodegradable polycarbonate nanofibers and to investigate their biodegradability by different enzymes. Poly(2,3-dihydroxycarbonate) was synthesized from naturally occurring l-tartaric acid. The hydroxyl groups on the functional polycarbonate were converted to methacrylate groups to enable the polymer to cross-link under UV irradiation. Smooth cross-linked methacrylated polycarbonate nanofibers (300-1800 nm) were fabricated by a reactive electrospinning process with in situ UV radiation from a mixed solution of linear methacrylated polycarbonate (MPC) and poly(ethylene oxide) (PEO) (MPC:PEO = 9:1) in methanol/chloroform (50/50). These cross-linked nanofibers have shown excellent solvent resistance and their solubility decreases with increasing degree of cross-linking. The thermal properties of linear and cross-linked polycarbonate nanofibers were investigated by differential scanning calorimetry and thermogravimetric analysis. The cross-linked polycarbonate nanofibers show no melting point below 200 °C and their decomposition temperature increases with increasing cross-linking degree. Their biodegradation products by five different enzymes were analyzed using liquid chromatography-mass spectrometry (LC-MS). The biodegradability of the polycarbonate nanofibers decreases with increasing cross-linking degree. These nanofibers were found to support human fibroblast survival and to promote cell attachment. This study demonstrates that cross-linked biodegradable polycarbonate nanofibers with different chemical properties and biodegradability can be fabricated using the novel reactive electrospinning technology to meet the needs of different biomedical applications.

  19. Determination of thermodynamic properties of poly (cyclohexyl methacrylate) by inverse gas chromatography.

    PubMed

    Kaya, Ismet; Pala, Cigdem Yigit

    2014-07-01

    In this work, some thermodynamic properties of poly (cyclohexyl methacrylate) were studied by inverse gas chromatography (IGC). For this purpose, the polymeric substance was coated on Chromosorb W and which was filled into a glass column. The retention times (t(r)) of the probes were determined from the interactions of poly (cyclohexyl methacrylate) with n-pentane, n-hexane, n-heptane, n-octane, n-decane, methanol, ethanol, 2-propanol, butanol, acetone, ethyl methyl ketone, benzene, toluene and o-xylene by IGC technique. Then, the specific volume (Vg(0)) was determined for each probe molecule. By using (1/T; lnVg(0)) graphics, the glass transition temperature of poly (cyclohexyl methacrylate) was found to be 373 K. The adsorption heat under the glass transition temperature (deltaH(a)), and partial molar heat of sorption above the glass transition (deltaH1(S)), partial molar free energy of sorption (deltaG1(S)) and partial molar entropy of sorption (deltaS1(S)) belonging to sorption for every probe were calculated. The partial molar heat of mixing at infinite dilution (deltaH1(infinity)), partial molar free energy of mixing at infinite dilution (deltaG1(infinity)), Flory-Huggins interaction parameter (chi12(infinity)) and weight fraction activity coefficient (a1/w1)(infinity) values of polymer-solute systems were calculated at different column temperatures. The solubility parameters (delta2) of the polymer were obtained by IGC technique. PMID:25255568

  20. 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.

  1. Hypercalcemia secondary to granulomatous disease caused by the injection of methacrylate: a case series

    PubMed Central

    Negri, Armando Luis; Rosa Diez, Guillermo; Del Valle, Elisa; Piulats, Elsa; Greloni, Gustavo; Quevedo, Alejandra; Varela, Federico; Diehl, Maria; Bevione, Pablo

    2014-01-01

    Summary Association of dysregulated calcium homeostasis and granulomatous disease is well established. There exist reports in the literature of granulomatous reactions produced by silicones associated with hypercalcemia. In this case series we report four young women that underwent methacrylate injections in gluteus, thighs and calves that developed granulomas with posterior appearance of hypercalcemia. This complication presented as subacute around 6 months after the procedure. The four patients have as common elements the presence of moderate to severe renal insufficiency, suppressed PTH and elevated calcitriol levels for the degree of renal function. In the image studies, two patients presented in the nuclear magnetic resonance of the gluteus hypodense nodular images compatible with granulomas. Two patients had a positron emission tomography performed showing increased metabolic activity in the muscles of the gluteal region compatible with granulomas. Two patients had a partial surgical resection of the gluteal lesions with the finding of methacrylate associated to foreign body granulomas. In these patients hypercalcemia was treated with oral or local injections of corticoids, intravenous bisphosphonates or ketoconazole with good response. Although the prevalence of this complication with methacrylate injection is not common, hypercalcemia secondary to granulomas should be considered in the differential diagnosis of patients with hypercalcemia when there is a history of this procedure, and especially if they have a reduction in their renal function. PMID:25002879

  2. Nano-Sized Sunflower Polycations As Effective Gene Transfer Vehicles.

    PubMed

    Cheng, Yilong; Wei, Hua; Tan, James-Kevin Y; Peeler, David J; Maris, Don O; Sellers, Drew L; Horner, Philip J; Pun, Suzie H

    2016-05-01

    The architecture of polycations plays an important role in both gene transfection efficiency and cytotoxicity. In this work, a new polymer, sunflower poly(2-dimethyl amino)ethyl methacrylate) (pDMAEMA), is prepared by atom transfer radical polymerization and employed as nucleic acid carriers compared to linear pDMAEMA homopolymer and comb pDMAEMA. The sunflower pDMAEMAs show higher IC50 , greater buffering capacity, and stronger binding capacity toward plasmid DNA than their linear and comb counterparts. In vitro transfection studies demonstrate that sunflower pDMAEMAs exhibit high transfection efficiency as well as relatively low cytotoxicity in complete growth medium. In vivo gene delivery by intraventricular injection to the brain shows that sunflower polymer delivers plasmid DNA more effectively than comb polymer. This study provides a new insight into the relationship between polymeric architecture and gene delivery capability, and as well as a useful means to design potent vectors for successful gene delivery. PMID:27061622

  3. Hot embossing and thermal bonding of poly(methyl methacrylate) microfluidic chips using positive temperature coefficient ceramic heater.

    PubMed

    Wang, Xia; Zhang, Luyan; Chen, Gang

    2011-11-01

    As a self-regulating heating device, positive temperature coefficient ceramic heater was employed for hot embossing and thermal bonding of poly(methyl methacrylate) microfluidic chip because it supplied constant-temperature heating without electrical control circuits. To emboss a channel plate, a piece of poly(methyl methacrylate) plate was sandwiched between a template and a microscopic glass slide on a positive temperature coefficient ceramic heater. All the assembled components were pressed between two elastic press heads of a spring-driven press while a voltage was applied to the heater for 10 min. Subsequently, the embossed poly(methyl methacrylate) plate bearing negative relief of channel networks was bonded with a piece of poly(methyl methacrylate) cover sheet to obtain a complete microchip using a positive temperature coefficient ceramic heater and a spring-driven press. High quality microfluidic chips fabricated by using the novel embossing/bonding device were successfully applied in the electrophoretic separation of three cations. Positive temperature coefficient ceramic heater indicates great promise for the low-cost production of poly(methyl methacrylate) microchips and should find wide applications in the fabrication of other thermoplastic polymer microfluidic devices.

  4. Effect of curing environment on mechanical properties and polymerizing behaviour of methyl-methacrylate autopolymerizing resin.

    PubMed

    Ogawa, T; Hasegawa, A

    2005-03-01

    Methyl-methacrylate autopolymerizing resin is used for multiple applications. Therefore, the mechanical properties of autopolymerizing resin should be assessed comprehensively including strength, stiffness and hardness. Any methods that effectively improve these mechanical properties are desirable. The objective of this study is to examine the effects of the curing environment: air or water with/without pressure, and air or water temperature during polymerization, on the strength, stiffness and hardness of autopolymerizing resin. In addition, we examined the polymerizing behaviour associated with the mechanical properties. Autopolymerizing methyl-methacrylate resin (Unifast II) was polymerized under the following conditions: in air and water with/without pressure at 10, 23, 30, 40, 60 and 80 degrees C. The resin specimens were subjected to a transverse test (three-point flexural test) and micro-Brinell surface hardness test. Fractured surfaces of the specimens after the transverse test were examined using a scanning electron microscope (SEM). The transverse strength and transverse modulus increased with increasing curing temperature in both wet and dry conditions. Pressured wet conditions increased transverse strength and transverse modulus over non-pressured wet and dry conditions. The resin polymerized in dry conditions showed higher surface hardness than the one polymerized in wet conditions at matching temperature. The SEM images of fractured surfaces cured at lower temperature exhibited porosity within the polymer base and cracks between the base and poly-methyl-methacrylate (PMMA) particulates. Surfaces of the resin polymerized in wet conditions were characterized with PMMA particulates having rougher surfaces suggestive of water incorporation. Raising temperature and pressuring during polymerization increase strength and stiffness of autopolymerizing resin. However, wet condition reduces surface hardness of resin compared with dry condition. These altered

  5. Flexural Strength Comparison of Silorane- and Methacrylate-Based Composites with Pre-impregnated Glass Fiber

    PubMed Central

    Doozandeh, Maryam; Alavi, Ali Asghar; Karimizadeh, Zahra

    2016-01-01

    Statement of the Problem Sufficient adhesion between silorane/methacrylate-based composites and methacrylate impregnated glass fiber increases the benefits of fibers and enhances the mechanical and clinical performance of both composites. Purpose The aim of this study was to evaluate the compatibility of silorane and methacrylate-based composites with pre-impregnated glass fiber by using flexural strength (FS) test. Materials and Method A total of 60 bar specimens were prepared in a split mold (25×2×2 mm) in 6 groups (n=10). In groups 1 and 4 (control), silorane-based (Filtek P90) and nanohybrid (Filtek Z350) composites were placed into the mold and photopolymerized with a high-intensity curing unit. In groups 2 and 5, pre-impregnated glass fiber was first placed into the mold and after two minutes of curing, the mold was filled with respective composites. Prior to filling the mold in groups 3 and 6, an intermediate adhesive layer was applied to the glass fiber. The specimens were stored in distilled water for 24 hours and then their flexural strength was measured by 3 point bending test, using universal testing machine at the crosshead speed of 1 mm/min. Two-way ANOVA and post-hoc test were used for analyzing the data (p< 0.05). Results A significant difference was observed between the groups (p< 0.05). The highest FS was registered for combination of Z350 composite, impregnated glass fiber, and application of intermediate adhesive layer .The lowest FS was obtained in Filtek P90 alone. Cohesive failure in composite was the predominant failure in all groups, except group 5 in which adhesive failure between the composite and fiber was exclusively observed. Conclusion Significant improvement in FS was achieved for both composites with glass fiber. Additional application of intermediate adhesive layer before composite build up seems to increase FS. Nanohybrid composite showed higher FS than silorane-based composite. PMID:27284555

  6. Utilization of Methacrylates and Polymer Matrices for the Synthesis of Ion Specific Resins

    SciTech Connect

    Czerwinski, Kenneth

    2013-10-29

    Disposal, storage, and/or transmutation of actinides such as americium (Am) will require the development of specific separation schemes. Existing efforts focus on solvent extraction systems for achieving suitable separation of actinide from lanthanides. However, previous work has shown the feasibility of ion-imprinting polymer-based resins for use in ion-exchange-type separations with metal ion recognition. Phenolic-based resins have been shown to function well for Am-Eu separations, but these resins exhibited slow kinetics and difficulties in the imprinting process. This project addresses the need for new and innovative methods for the selective separation of actinides through novel ion-imprinted resins. The project team will explore incorporation of metals into extended frameworks, including the possibility of 3D polymerized matrices that can serve as a solid-state template for specific resin preparation. For example, an anhydrous trivalent f-element chain can be formed directly from a metal carbonate, and methacrylic acid from water. From these simple coordination complexes, molecules of discrete size or shape can be formed via the utilization of coordinating ligands or by use of an anionic multi-ligand system incorporating methacrylate. Additionally, alkyl methyl methacrylates have been used successfully to create template nanospaces, which underscores their potential utility as 3D polymerized matrices. This evidence provides a unique route for the preparation of a specific metal ion template for the basis of ion-exchange separations. Such separations may prove to be excellent discriminators of metal ions, even between f-elements. Resins were prepared and evaluated for sorption behavior, column properties, and proton exchange capacity.

  7. Moleculary imprinted polymers with metalloporphyrin-based molecular recognition sites coassembled with methacrylic acid.

    PubMed

    Takeuchi, T; Mukawa, T; Matsui, J; Higashi, M; Shimizu, K D

    2001-08-15

    A diastereoselective molecularly imprinted polymer (MIP) for (-)-cinchonidine, PPM(CD), was prepared by the combined use of methacrylic acid and vinyl-substituted zinc(II) porphyrin as functional monomers. Compared to MIPs using only methacrylic acid or zinc porphyrin as a functional monomer, PM(CD) and PP(CD), respectively, PPM(CD) showed higher binding ability for (-)-cinchonidine in chromatographic tests using the MIP-packed columns. Scatchard analysis gave a higher association constant of PPM(CD) for (-)-cinchonidine (1.14 x 10(7) M(-1)) than those of PP(CD) (1.45 x 10(6) M(-1)) and PM(CD) (6.78 x 10(6) M(-1)). The affinity distribution of binding sites estimated by affinity spectrum analysis showed a higher percentage of high-affinity sites and a lower percentage of low-affinity sites in PPM(CD). The MIPs containing a zinc(II) porphyrin in the binding sites, PPM(CD) and PP(CD), showed fluorescence quenching according to the binding of (-)-cinchonidine, and the quenching was significant in the low-concentration range, suggesting that the high-affinity binding sites contain the porphyrin residue. The correlation of the relative fluorescence intensity against log of (-)-cinchonidine concentrations showed a linear relationship. These results revealed that the MIP having highly specific binding sites was assembled by the two functional monomers, vinyl-substituted zinc(II) porphyrin and methacrylic acid, and they cooperatively worked to yield the specific binding. In addition, the zinc(II) porphyrin-based MIPs appeared to act as fluorescence sensor selectively responded by binding events of the template molecule.

  8. Nano-engineered optical properties of iodine doped poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Mehta, Sheetal; Keller, Jag Mohan; Das, Kallol

    2016-05-01

    Poly (methyl methacrylate) (PMMA) and Iodine hybrid matrixes have been prepared and characterized. The optical properties of the prepared I-PMMA hybrid composites were characterized by linear absorption studies and these composites have been found to contain embedded Iodine nanoparticles. The size of the nanoparticles was found to be a function of the Iodine content of PMMA. Refractive index measurements were undertaken for different wavelengths. The results showed that the refractive index of the composite is dependent on thermal annealing and also varies nonlinearly with the doping concentration at low Iodine concentration or in the region of nanoparticles formation.

  9. Quantitative analysis of (styrene/acrylonitrile/methyl methacrylate) co-polymer systems by infrared resonance spectroscopy

    NASA Astrophysics Data System (ADS)

    Jalbout, Abraham F.; Jiang, Tao; Fengqi, Liu; Ding, C.; Darwish, Abdalla M.

    2002-02-01

    A detailed careful analysis of the infrared resonance (IR) spectra of polystyrene (PSt), polymethyl methacrylate (PMMA), polyacrylonitrile (PAN) and their co-mixtures were performed. Through this study the absorption peak area to weight ratios as well as working curves were obtained to test for their reliability as well as their suitability. Satisfactory results were achieved and these working curves were then used to measure the polymerized components of binary and ternary co-polymers. By investigating the acquired data we conclude that the monomer preferential polymeric sequence is St>MMA>AN. A quantitative method to measure P (St/AN/MMA) concentrations by IR spectroscopy is proposed in this work.

  10. Vibrational overtone enhancement of methyl methacrylate polymerization initiated by benzoyl peroxide decomposition

    NASA Astrophysics Data System (ADS)

    Grinevich, Oleg; Snavely, D. L.

    1997-03-01

    Vibrational overtone initiated polymerization has been demonstrated using intracavity photolysis of a benzoyl peroxide/methyl methacrylate mixture. Excitation of the 6 νCH overtone transition of the ground electronic state of benzoyl peroxide creates radicals which subsequently begin the polymerization process. Polymer yield was monitored by comparison of the 2 νCH overtone absorptions for the methyl, methylenic and olefinic CH stretches at 5946 and 6170 cm -1, respectively. Plots of polymer yield versus time demonstrate an autoacceleration of the polymerization rate commencing many hours after the photolysis period. The delay before autoacceleration depends on the duration of the photolysis.

  11. Microstructure-property relationships in alumina trihydrate filled poly (methyl methacrylate) composite materials

    NASA Astrophysics Data System (ADS)

    Zhang, Ruoyu

    2015-07-01

    The mechanical properties (Young's modulus and fracture toughness) of composite made from a poly (methyl methacrylate) (PMMA) matrix filled with alumina trihydrate(ATH) are reported. The experiments were performed using flexural tests and single edge notched bend (SENB) tests. The composites samples were tested at a range of filler volume fractions (34.7%, 39.4% and 44.4%) and mean filler diameters (8 pm, 15 pm and 25 pm). The data of Young's modulus agreed well with the results of Lielens model and finite element analysis (FEA) model.

  12. Properties of cellulase as template molecule on chitosan—methyl methacrylate membrane

    NASA Astrophysics Data System (ADS)

    Lian, Qi; Zheng, Xuefang; Wu, Haixia; Song, Shitao; Wang, Dongjun

    2015-12-01

    In this study, a novel molecular imprinting membrane made of chitosan and methyl methacrylate (MMA) was fabricated with cellulase as template molecule and the thermal response to cellulase was characterized. The film was characterized by infrared spectroscopy (IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and the permeation experiment. The results showed that the space structure of the film was as similar as the cellulase. Moreover, the membrane had advanced molecular imprinting capability to cellulase comparing to pepsin and pectinase at any temperature and the film had excellent ability to identify specific template molecule (cellulase) at the synthesis temperature compared to other temperatures.

  13. Fracture resistance of Kevlar-reinforced poly(methyl methacrylate) resin: a preliminary study.

    PubMed

    Berrong, J M; Weed, R M; Young, J M

    1990-01-01

    The reinforcing effect of Kevlar fibers incorporated in processed poly(methyl methacrylate) resin samples was studied using 0% (controls), 0.5%, 1%, and 2% by weight of the added fibers. The samples were subjected to impact testing to determine fracture resistance, and sample groups were statistically compared using an ANOVA. Each reinforced sample had significantly greater fracture resistance (P less than 0.05) than the control, and no difference was found either within or between control groups. The use of reinforcing Kevlar fibers appears to enhance the fracture resistance of acrylic resin denture base materials.

  14. In-situ photopolymerization of monodisperse and discoid oxidized methacrylated alginate microgels in a microfluidic channel

    DOE PAGES

    Wang, Shuo; Jeon, Oju; Shankles, Peter G.; Liu, Yuan; Alsberg, Eben; Retterer, Scott T.; Lee, Bruce P.; Choi, Chang Kyoung

    2016-02-03

    Here, we present a simple microfluidic technique to in-situ photopolymerize (by 365 nm ultraviolet) monodisperse oxidized methacrylated alginate (OMA) microgels using a photoinitiator (VA-086). By this technique, we generated monodisperse spherical OMA beads and discoid non-spherical beads with better shape consistency than ionic crosslinking methods do. We found that a high monomer concentration (8 w/v %), a high photoinitiator concentration (1.5 w/v %) and absence of oxygen are critical factors to cure OMA microgels. This photopolymerizing method is an alternative to current methods to form alginate microgels and is a simpler approach to generate non-spherical alginate microgels.

  15. Novel synthesis of cellulose-based diblock copolymer of poly(hydroxyethyl methacrylate) by mechanochemical reaction.

    PubMed

    Ohura, Takeshi; Tsutaki, Yusaku; Sakaguchi, Masato

    2014-01-01

    The mechanical fracture of polymer produces polymeric free radical chain-ends, by which liner block copolymers have been synthesized. A diblock copolymer of microcrystalline cellulose (MCC) and poly 2-hydroxyethyl methacrylate (pHEMA) was produced by the mechanochemical polymerization under vacuum and room temperature. The fraction of pHEMA in MCC-block-pHEMA produced by the mechanochemical polymerization increased up to 21 mol% with increasing fracture time (~6 h). Then, the tacticities of HEMA sequences in MCC-block-pHEMA varied according to the reaction time. In the process of mechanochemical polymerization, cellulose could play the role of a radical polymerization initiator capable of controlling stereoregularity.

  16. Positronium Formation Of Glyeisdyl Methacrylic Acid (GMA)/Styrene Grafted On PVDF Membrane For Fuel Cells

    SciTech Connect

    Abdel-Hady, E. E.; Abdel-Hamed, M. O.; Eltonny, M. M.

    2011-06-01

    Simultaneous gamma irradiation was used effectively for grafting of glycidyl methacrylic acid and styrene onto Poly vinyldine fluoride (PVDF). Membranes were characterized by thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). The properties of the obtained membranes were evaluated in terms of proton conductivity, methanol permeability and positron annihilation lifetime (PALS) parameters. The high probability of Positronium formation enables the application of PALS to the study of free volume. Good property values approved the applicability of the membrane from the cost benefit point of view.

  17. Effects of preheating on the properties of silorane- and methacrylate-based composites.

    PubMed

    Dickson, Peggy L; Vandewalle, Kraig S; Lien, Wen; Wajdowicz, Michael N; Santos, Maria

    2014-01-01

    This study evaluated how preheating affected the properties of a silorane-based composite restorative material and 4 methacrylate-based composites. Viscosity, compressive strength, depth of cure, and polymerization shrinkage were examined. Data were analyzed with a 2-way ANOVA per physical property and composite type. With the exception of the flowable composite, significant reductions in viscosity were found between all preheated and room temperature composites, with no significant difference in other properties. In general, preheating the restorative composites decreased viscosity, but did not affect compressive strength, depth of cure, or shrinkage per composite type.

  18. Thermal response of polystyrene/poly methyl methacrylate (PS/PMMA) polymeric blends

    NASA Astrophysics Data System (ADS)

    Mathur, Vishal; Sharma, Kananbala

    2016-02-01

    The present paper reports the investigationsto evaluate thermal behavior of polystyrene/poly methyl methacrylate (PS/PMMA) polymeric blends, prepared at different compositions through solution casting method. The glass transition temperatures have been obtained using dynamic mechanical analyzer. Simultaneous measurements of temperature dependentthermal transport properties (thermal conductivity and thermal diffusivity) have been made using Hot Disk Thermal Constants Analyzer based on transient plane source. The study reveals that blending of PS with PMMA leads to different phase morphologies corresponding to different composition range which further affects the thermal performance of respective blends.

  19. Structure/property relationships in methacrylate/dimethacrylate polymers for dental applications

    NASA Astrophysics Data System (ADS)

    Mehlem, Jeremy John

    Since its invention Bis-GMA or one of its analogs has been the main component of the polymer portion of composites for dental restorations. The need for dilution of Bis-GMA and its analogs to optimize its properties has long been recognized. Bis-GMA is a highly viscous monomer. This high viscosity leads to early vitrification, which limits conversion during cure. This viscosity also limits filler loading. Vitrification at low conversions leads to heterogeneous systems composed of low and high cross-link density phases. The low cross-link density phases behave as defects in the system; therefore, if the amount of low cross-link density phases in the system can be reduced and a more uniform network structure can be achieved, then the mechanical properties of the resin can be improved. Since the increase in viscosity during cure causes vitrification, it is logical that a system with a low initial viscosity will delay the onset of vitrification. Reactive diluents such as triethylene glycol dimethacrylate (TEGDMA) are effective at lower levels. However, large amounts negatively affect matrix properties by increasing polymerization shrinkage and water sorption. Shrinkage has been cited as one of the main deficiencies in dental composites. The goal of this project is to improve upon standard viscosity modifying comonomers such as triethylene glycol dimethacrylate. The comonomers that were explored were phenyloxyethyl methacrylate, cyclohexyl methacrylate, and tert-butylcylcohexyl methacrylate. Multicomponent systems based on analogs of ethylene glycol dimethacrylates with different length ethyl glycol chains were also examined. The substitution of monomethacrylates for TEGDMA as a comonomer resulted in enhanced or negligible affects on the mechanical properties of Bis-MEPP based polymer systems while reducing polymerization shrinkage. 129Xenon NMR and TappingMode(TM) AFM were used to characterize the heterogeneity of dimethacrylates systems during their cure cycle as well

  20. Amine functionalization of cellulose surface grafted with glycidyl methacrylate by γ-initiated RAFT polymerization

    NASA Astrophysics Data System (ADS)

    Barsbay, Murat; Güven, Olgun; Kodama, Yasko

    2016-07-01

    This study presents the functionalization of poly(glycidyl methacrylate) (PGMA) grafted cellulose filter paper by a model compound, ethylenediamine (EDA), through the epoxy groups of PGMA. Cellulose based copolymers were prepared via the radiation-induced and RAFT-mediated graft polymerization. The samples were characterized by ATR-FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS), elemental analysis, contact angle measurements and scanning electron microscopy (SEM). An efficient modification density of around 1 mmol EDA/mg copolymer was attained within ca. 8 h, indicating that chemical composition of well-defined copolymers may further be tuned by appropriately selecting the reactive agents for use in many emerging fields.

  1. Grafting of Methacrylonitrile and Ethyl Methacrylate onto Jute Fibre: Physico-chemical Characteristics of Grafted Jute

    NASA Astrophysics Data System (ADS)

    Mondal, Md. Ibrahim H.; Islam Farouqui, Faisul; Abu Hanif, Md.; Shafiur Rahman, G. M.; Asadul Hoque, Md.

    2005-10-01

    Modification of bleached jute fibre was done by graft co-polymerization with vinyl monomers e.g. methacrylonitrile and ethyl methacrylate, in aqueous medium using H2O2-Na2S2O3 as redox initiators. To make the process efficient, the optimized polymerization condition was established. The maximum percent grafting and grafting efficiency obtained at optimum grafting condition were 11.3 and 20.4% for MAN, respectively and that of 17.6 and 27.5% for EMA. Modification of bleached jute fibre with MAN and EMA reduced the loss in breaking strength and the yellowing on exposure to sunlight in air.

  2. Controlling of optical energy gap of Co-ferrite quantum dots in poly (methyl methacrylate) matrix

    NASA Astrophysics Data System (ADS)

    El-Sayed, H. M.; Agami, W. R.

    2015-07-01

    Different crystallite sizes of Co-ferrite nanoparticles were prepared and dispersed in the matrix of poly (methyl methacrylate) (PMMA) polymer. The effect of crystallite size on the structure and optical energy gap of Co-nanoferrite/PMMA composite has been studied. The optical energy gap of Co-ferrite was greatly affected by the crystallite size. This result was discussed in terms of the formation of electron-hole exciton using particle in a box model. The effective mass and the Bohr radius of the formed exciton have been calculated from the spectroscopic measurements.

  3. Far infrared-assisted encapsulation of filter paper strips in poly(methyl methacrylate) for proteolysis.

    PubMed

    Chen, Qiwen; Bao, Huimin; Zhang, Luyan; Chen, Gang

    2016-02-01

    Filter paper strips were enclosed between two poly(methyl methacrylate) plates to fabricate paper-packed channel microchips under pressure in the presence of far infrared irradiation. After the enclosed paper strip was oxidized by periodate, trypsin was covalently immobilized in them to fabricate microfluidic proteolysis bioreactor. The feasibility and performance of the unique bioreactor were demonstrated by digesting BSA and lysozyme. The results were comparable to those of conventional in-solution proteolysis while the digestion time was significantly reduced to ∼18 s. The suitability of the microfluidic paper-based bioreactors to complex proteins was demonstrated by digesting human serum.

  4. Generalized peripheral neuropathy in a dental technician exposed to methyl methacrylate monomer

    SciTech Connect

    Donaghy, M.; Rushworth, G.; Jacobs, J.M. )

    1991-07-01

    A 58-year-old dental prosthetic technician developed generalized sensorimotor peripheral neuropathy. Neurophysiologic studies showed a generalized sensorimotor neuropathy of axonal degeneration type. Examination of a sural nerve biopsy showed a moderately severe axonal neuropathy with loss of large myelinated fibers and unmyelinated axons. There was evidence of slow ongoing degeneration and considerable fiber regeneration. Electron microscopy showed increased numbers of filaments in a few fibers. These findings show resemblances to the nerve changes caused by another acrylic resin, acrylamide. They suggest that the neuropathy may have been caused by 30 years of occupational cutaneous and inhalational exposure to methyl methacrylate monomer since they excluded other recognized causes of neuropathy.

  5. Synthesis and swelling behavior of Protein-g-poly Methacrylic acid/kaolin superabsorbent hydrogel composites

    NASA Astrophysics Data System (ADS)

    Sadeghi, Mohammad

    2008-08-01

    A novel superabsorbent hydrogel composite based on Collagen have been prepared via graft copolymerization of Methacrylic acid (MAA) in the presence of kaolin powder using methylenebisacrylamide (MBA) as a crosslinking agent and ammonium persulfate (APS) as an initiator. The composite structure was confirmed using FTIR spectroscopy. A new absorption band at 1728 cm-1 in the composite spectrum confirmed kaolin-organic polymer linkage. The effect of kaolin amount and MBA concentration showed that with increasing of these parameters, the water absorbency of the superabsorbent composite was decreased. The swelling measurements of the hydrogels were conducted in aqueous salt solutions.

  6. Temperature dependence properties of holographic gratings in phenanthrenquinone doped poly(methyl methacrylate) photopolymers.

    PubMed

    Russo, Juan Manuel; Kostuk, Raymond K

    2007-10-20

    We examine the temperature dependence of edge-illuminated holographic filters formed in phenanthrenquinone doped poly(methyl methacrylate) (PQ/PMMA) operating at 1550 nm. It was found that the thermally induced change to the refractive index and volume can be used to select the wavelength filtered by the grating. The temperature can be varied over a range of 15 degrees C without introducing noticeable hysteresis effects. The wavelength can be tuned at a rate of 0.03 nm/degrees C over this temperature range. A model for the temperature tuning effect is presented and compared to experimental results.

  7. Supported nickel bromide catalyst for atom transfer radical polymerization (ATRP) of methyl methacrylate.

    PubMed

    Duquesne, E; Degée, Ph; Habimana, J; Dubois, Ph

    2004-03-21

    A new supported catalytic system, i.e. nickel bromide catalyst ligated by triphenylphosphine (TPP) ligands immobilized onto crosslinked polystyrene resins (PS-TPP) is reported. Per se, this catalyst does not allow any control over the polymerization of methyl methacrylate (MMA) initiated by ethyl 2-bromoisobutyrate but, in the presence of a given amount of purposely added free TPP, it promotes controlled ATRP of MMA. Indeed colorless PMMA chains of low polydispersity indices are readily recovered, the molecular weight of which linearly increases with monomer conversion and agrees with the expected values. Recycling of the supported catalyst is evidenced and does not prevent the polymerization from being controlled. PMID:15010758

  8. Viscoelastic properties of polycarbonate, poly(methyl methacrylate) and their nanocomposites via nanoindentation experiments

    NASA Astrophysics Data System (ADS)

    Noll, Kenneth; Wong, Maranda; Evke, Erin; Rende, Deniz; Ozisik, Rahmi

    2014-03-01

    Polycarbonate, PC, and poly(methyl methacrylate), PMMA, are economic alternatives to glass mainly die to their mecahnical and optical properties. The uses of PC and PMMA can be expanded if their impact response and scratch resistance are improved. Carbon nanotubes are known to increase the toughness of PMMA and improve its resistance impact forces. In the current study, the viscoelastic properties of PC, PMMA and their nanocomposites were investigated via nanoindentation experiments. Stress relaxation experiments were performed under various loading rates._ The material is partially based upon work supported by NSF under Grant Nos. 1200270 and 1003574.

  9. Aquatic toxicity of acrylates and methacrylates: quantitative structure-activity relationships based on Kow and LC50

    SciTech Connect

    Reinert, K.H.

    1987-12-01

    Recent EPA scrutiny of acrylate and methacrylate monomers has resulted in restrictive consent orders and Significant New Use Rules under the Toxic Substances Control Act, based on structure-activity relationships using mouse skin painting studies. The concern is centered on human health issues regarding worker and consumer exposure. Environmental issues, such as aquatic toxicity, are still of concern. Understanding the relationships and environmental risks to aquatic organisms may improve the understanding of the potential risks to human health. This study evaluates the quantitative structure-activity relationships from measured log Kow's and log LC50's for Pimephales promelas (fathead minnow) and Carassius auratus (goldfish). Scientific support of the current regulations is also addressed. Two monomer classes were designated: acrylates and methacrylates. Spearman rank correlation and linear regression were run. Based on this study, an ecotoxicological difference exists between acrylates and methacrylates. Regulatory activities and scientific study should reflect this difference.

  10. Chemically induced graft copolymerization of 2-hydroxyethyl methacrylate onto polyurethane surface for improving blood compatibility

    NASA Astrophysics Data System (ADS)

    He, Chunli; Wang, Miao; Cai, Xianmei; Huang, Xiaobo; Li, Li; Zhu, Haomiao; Shen, Jian; Yuan, Jiang

    2011-11-01

    To improve hydrophilicity and blood compatibility properties of polyurethane (PU) film, we chemically induced graft copolymerization of 2-hydroxyethyl methacrylate (HEMA) onto the surface of polyurethane film using benzoyl peroxide as an initiator. The effects of grafting temperature, grafting time, monomer and initiator concentrations on the grafting yields were studied. The maximum grafting yield value was obtained 0.0275 g/cm2 for HEMA. Characterization of the films was carried out by attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), water contact angle measurements. ATR-FTIR data showed that HEMA was successfully grafted onto the PU films surface. Water contact angle measurement demonstrated the grafted films possessed a relatively hydrophilic surface. The blood compatibility of the grafted films was preliminarily evaluated by a platelet-rich plasma adhesion test and hemolysis test. The results of platelet adhesion experiment showed that polyurethane grafted polymerization with monomer of 2-hydroxyethyl methacrylate had good blood compatibility featured by the low platelet adhesion. Hemolysis rate of the PU-g-PHEMA films was dramatically decreased than the ungrafted PU films. This kind of new biomaterials grafted with HEMA monomers might have a potential usage for biomedical applications.

  11. Modulation of barnacle (Balanus amphitrite Darwin) cyprid settlement behavior by sulfobetaine and carboxybetaine methacrylate polymer coatings.

    PubMed

    Aldred, Nick; Li, Guozhu; Gao, Ye; Clare, Anthony S; Jiang, Shaoyi

    2010-08-01

    Zwitterionic polymers such as poly(sulfobetaine methacrylate) (polySBMA) and poly(carboxybetaine methacrylate) (polyCBMA) have demonstrated impressive fouling-resistance against proteins and mammalian cells. In this paper, the effects of these surface chemistries on the settlement and behavior of an ubiquitous fouling organism, the cypris larva of the barnacle Balanus amphitrite (=Amphibalanus amphitrite), were studied in the laboratory. Conventional settlement assays and behavioral analysis of cyprids using Noldus Ethovision 3.1 demonstrated significant differences in settlement and behavior on different surfaces. Cyprids did not settle on the polySBMA or polyCBMA surfaces over the course of the assay, whereas settlement on glass occurred within expected limits. Individual components of cyprid behavior were shown to differ significantly between glass, polySBMA and polyCBMA. Cyprids also responded differently to the two zwitterionic surfaces. On polySBMA, cyprids were unwilling or unable to settle, whereas on polyCBMA cyprids did not attempt exploration and left the surface quickly. In neither case was toxicity observed. It is concluded that a zwitterionic approach to fouling-resistant surface development has considerable potential in marine applications. PMID:20658383

  12. Photoinitiated chemical vapor deposition of cytocompatible poly(2-hydroxyethyl methacrylate) films.

    PubMed

    McMahon, Brian J; Pfluger, Courtney A; Sun, Bing; Ziemer, Katherine S; Burkey, Daniel D; Carrier, Rebecca L

    2014-07-01

    Poly(2-hydroxyethyl methacrylate) (pHEMA) is a widely utilized biomaterial due to lack of toxicity and suitable mechanical properties; conformal thin pHEMA films produced via chemical vapor deposition (CVD) would thus have broad biomedical applications. Thin films of pHEMA were deposited using photoinitiated CVD (piCVD). Incorporation of ethylene glycol diacrylate (EGDA) into the pHEMA polymer film as a crosslinker, confirmed via Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy, resulted in varied swelling and degradation behavior. 2-Hydroxyethyl methacrylate-only films showed significant thickness loss (up to 40%), possibly due to extraction of low-molecular-weight species or erosion, after 24 h in aqueous solution, whereas films crosslinked with EGDA (9.25-12.4%) were stable for up to 21 days. These results differ significantly from those obtained with plasma-polymerized pHEMA, which degraded steadily over a 21-day period, even with crosslinking. This suggests that the piCVD films differ structurally from those fabricated via plasma polymerization (plasma-enhanced CVD). piCVD pHEMA coatings proved to be good cell culture materials, with Caco-2 cell attachment and viability comparable to results obtained on tissue-culture polystyrene. Thus, thin film CVD pHEMA offers the advantage of enabling conformal coating of a cell culture substrate with tunable properties depending on method of preparation and incorporation of crosslinking agents.

  13. Reaction of pectin and glycidyl methacrylate and ulterior formation of free films by reticulation.

    PubMed

    Maior, João Fhilype Andrade Souto; Reis, Adriano Valim; Muniz, Edvani C; Cavalcanti, Osvaldo Albuquerque

    2008-05-01

    In this work, low-methoxyl pectin was chemically modified by reaction with glycidyl methacrylate (GMA) to give a material with low hydrosolubility. After physio-chemical characterization by FT-IR, DSC, and TGA analyses, the methacrylated/modified pectin (Pect-GMA) was crosslinked after the addition of sodium persulfate (SP), that actuates as initiator, at 50 degrees C for 24 and 48h either in the presence or not of aqueous polymethacrylate dispersion (Eudragit RS 30 D) to obtain free films by Teflon plate "casting" process. Different Pect-GMA/Eudragit RS 30 D ratios and SP concentrations were used. The free films were characterized by the determination of water vapor transmission (WVT), the swelling index (Ieq%) in simulated gastric (SGF) and intestinal (SIF) fluids, and by scanning electron microscopy (SEM). The presence of ionized groups in Pect-GMA turned the films pH-dependent because Ieq% of swollen crosslinked Pect-GMA films was larger at pH 6.8 than at pH 1.2. This was confirmed by the large pore size observed in the micrographs of SIF-swollen lyophilized films. In this way, films containing Pect-GMA and Eudragit RS 30 D, a time-dependent polymer, may present a synergistic action that favors specific biodegradation of the film in distal end of the gastrointestinal tract (GIT) by enzymes produced by the colonic microflora, enabling the modification of the release kinetics of drugs.

  14. Effect of Nanoclay on Thermal Conductivity and Flexural Strength of Polymethyl Methacrylate Acrylic Resin

    PubMed Central

    Ghaffari, Tahereh; Barzegar, Ali; Hamedi Rad, Fahimeh; Moslehifard, Elnaz

    2016-01-01

    Statement of the Problem The mechanical and thermal properties of polymethyl methacrylate (PMMA) acrylic resin should be improved to counterweigh its structural deficiencies. Purpose The aim of this study was to compare the flexural strength and thermal conductivity of conventional acrylic resin and acrylic resin loaded with nanoclay. Materials and Method The methacrylate monomer containing the 0.5, 1 and 2 wt% of nanoclay was placed in an ultrasonic probe and mixed with the PMMA powder. Scanning electron microscopy was used to verify homogeneous distribution of particles. Twenty-four 20×20×200-mm cubic samples were prepared for flexural strength test; 18 samples containing nanoclay and 6 samples for the control group. Another 24 cylindrical samples of 38×25 mm were prepared for thermal conductivity test. One-way ANOVA was used for statistical analysis, followed by multiple-comparison test (Scheffé’s test). Statistical significance was set at p< 0.05. Results Increasing the concentration of nanoclay incorporated into the acrylic resin samples increased thermal conductivity but decreased flexural strength (p< 0.05). Conclusion Based on the results of this study, adding nanoclay particles to PMMA improved its thermal conductivity, while it had a negative effect on the flexural strength. PMID:27284557

  15. Cellulose nanocrystal-poly(oligo(ethylene glycol) methacrylate) brushes with tunable LCSTs.

    PubMed

    Grishkewich, Nathan; Akhlaghi, Seyedeh Parinaz; Zhaoling, Yao; Berry, Richard; Tam, Kam C

    2016-06-25

    This paper reports on the synthesis of poly(oligoethylene glycol) methyl ether acrylate (POEGMA) grafted cellulose nanocrystals (CNCs) via surface initiated atom transfer radical polymerization (ATRP). An ATRP initiator (α-Bromoisobutyryl bromide) was covalently bonded to the surface of CNCs, followed by copolymerizing di(ethylene glycol) methyl ether methacrylate (MEO2MA) and oligoethylene glycol methyl ether methacrylate (OEGMA300) monomers from the surface using Cu(I)Br/2,2-dipyridal. Multiple POEGMA-g-CNC systems with varying MEO2MA/OEGMA300 content were synthesized, and they displayed a range of lower critical solution temperatures (LCSTs) in aqueous medium. μDSC endotherms and microstructural analysis indicated the collapse of POEGMA chains, followed by the aggregation of nanoparticles above their LCSTs. Cloud point measurements demonstrated a hysteresis in the heating and cooling of the POEGMA-g-CNC systems. It was found that the LCST of the nanoparticles could be tuned to between 23.8 to 63.8°C by adjusting the OEGMA300 content of the POEGMA brushes. PMID:27083811

  16. Analyses of preservatives by capillary electrochromatography using methacrylate ester-based monolithic columns.

    PubMed

    Huang, Hsi-Ya; Chiu, Chen-Wen; Huang, I-Yun; Yeh, Jui-Ming

    2004-10-01

    Five common food preservatives were analyzed by capillary electrochromatography, utilizing a methacrylate ester-based monolithic capillary as separation column. In order to optimize the separation of these preservatives, the effects of the pore size of the polymeric stationary phase, the pH and composition of the mobile phase on separation were examined. For all analytes, it was found that an increase in pore size caused a reduction in retention time. However, separation performances were greatly improved in monolithic columns with smaller pore sizes. The pH of the mobile phase had little influence on separation resolution, but a dramatic effect on the amount of sample that was needed to be electrokinetically injected into the monolithic column. In addition, the retention behaviors of these analytes were strongly influenced by the level of acetonitrile in the mobile phase. An optimal separation of the five preservatives was obtained within 7.0 min with a pH 3.0 mobile phase composed of phosphate buffer and acetonitrile 35:65 v/v. Finally, preservatives in real commercial products, including cold syrup, lotion, wine, and soy sauces, were successfully determined by the methacrylate ester-based polymeric monolithic column under this optimized condition.

  17. Radiopacity of Methacrylate and Silorane Composite Resins Using a Digital Radiographic System

    PubMed Central

    Firoozmand, Leily Macedo; Cordeiro, Mariana Gonçalves; Da Silva, Marcos André dos Santos

    2016-01-01

    The aim of this study was to evaluate the radiopacity of silorane and methacrylate resin composites, comparing them to the enamel, dentin, and aluminum penetrometer using a digital image. From six resin composites (Filtek™ P90, Filtek Z350, Filtek Z350 XT flow, Tetric Ceram, TPH Spectrum, and SureFil SDR flow) cylindrical disks (5 × 1 mm) were made and radiographed by a digital method, together with a 15-step aluminum step-wedge and a 1 mm slice of human tooth. The degree of radiopacity of each image was quantified using digital image processing. The mean values of the shades of gray of the tested materials were measured and the equivalent width of aluminum was calculated for each resin. The results of our work yielded the following radiopacity values, given here in descending order: Tetric Ceram > TPH > SDR > Z350 > Z350 flow > P90 > enamel > dentin. The radiopacity of the materials was different both for the enamel and for the dentin, except for resin P90, which was no different than enamel. In conclusion, silorane-based resin exhibited a radiopacity higher than dentin and closest to the enamel; a large portion of the methacrylate-based flow and conventional resins demonstrated greater radiopacity in comparison to dentin and enamel. PMID:27722199

  18. Effect of Montmorillonite Modification on Ultra Violet Radiation Cured Nanocomposite Filled with Glycidyl Methacrylate Modified Kenaf

    NASA Astrophysics Data System (ADS)

    Rozyanty, A. R.; Rozman, H. D.; Zhafer, S. F.; Musa, L.; Zuliahani, A.

    2016-06-01

    In this study nanocomposite cured by ultra violet radiation, were produced using modified montmorillonite (MMT) as reinforcing agent, chemically modified kenaf bast fiber as filler and unsaturated polyester as the matrix. Kenaf bast fiber was chemically modified with glycidyl methacrylate (GMA) whilst MMT were modified with cetyl trimethyl ammonium bromide (CTAB) and glycidyl methacrylate (GMA). Fixed 12 percent of GMA modified kenaf bast fiber with different percentage (i.e., 1, 3 and 5) of unmodified and modified MMT loading was used to produce the composite. The performed of GMA reaction with hydroxyl group of cellulose in kenaf bast fiber was evaluated using Fourier Transform infrared (FTIR) spectroscopy. GMA-MMT filled composite showed higher mechanical properties than MMT and CTAB-MMT filled composite. However, the increase of MMT, CTAB-MMT and GMA- MMT loading resulted in the reduction of mechanical properties. Scanning electron microscopy (SEM) analysis showed the evidence of compatibility enhancement between MMT and kenaf bast fiber with unsaturated polyester matrix.

  19. Binding of leachable components of polymethyl methacrylate (PMMA) and peptide on modified SPR chip

    NASA Astrophysics Data System (ADS)

    Szaloki, M.; Vitalyos, G.; Harfalvi, J.; Hegedus, Cs

    2013-12-01

    Many types of polymers are often used in dentistry, which may cause allergic reaction, mainly methyl methacrylate allergy due to the leachable, degradable components of polymerized dental products. The aim of this study was to investigate the interaction between the leachable components of PMMA and peptides by Fourier-transform Surface Plasmon Resonance (FT SPR). In our previous work binding of oligopeptides (Ph.D.-7 and Ph.D.-12 Peptide Library Kit) was investigated to PMMA surface by phage display technique. It was found that oligopeptides bounded specifically to PMMA surface. The most common amino acids were leucine and proline inside the amino acids sequences of DNA of phages. The binding of haptens, as formaldehyde and methacrylic acid, to frequent amino acids was to investigate on the modified gold SPR chip. Self assembled monolayer (SAM) modified the surface of gold chip and ensured the specific binding between the haptens and amino acids. It was found that amino acids bounded to modified SPR gold and the haptens bounded to amino acids by creating multilayer on the chip surface. By the application of phage display and SPR modern bioanalytical methods the interaction between allergens and peptides can be investigated.

  20. Synthesis of methyl methacrylate from coal-derived syngas: Quarterly report,, October 1-December 31, 1997

    SciTech Connect

    1998-09-01

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas that consists of three steps of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Over the last quarter, Eastman developed two new processes which have resulted in two new invention reports. One process deals with carbonylation of benzyl ether which represents a model for coal liquefaction and the second focuses on the acceleration of carbonylation rates for propionic acid synthesis, via use of polar aprotic solvents. These two inventions are major improvements in the novel Mo-catalyzed homogeneous process for propionic acid synthesis technology, developed by Eastman. Over the last quarter, RTI completed three reaction cycles and two regeneration cycles as a part of long-term reaction regeneration cycle study on a 10% Nb{sub 2}O{sub 5}/Si0{sub 2} catalyst, for vapor phase condensation reaction of formaldehyde with propionic acid.

  1. Synthesis of acrylates and methacrylates from coal-derived syngas. Quarterly report, October--December 1996

    SciTech Connect

    1997-05-02

    Research Triangle Institute (RTI), Eastman Chemical Company, and Bechtel collectively are developing a novel process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas, under a contract from the US Department of Energy, Federal Energy Technology Center. This three-step process consists of synthesis of a propionate, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) with methanol to produce MMA. Eastman has focused on the propionate synthesis step. the resultant Mo catalysts work efficiently at much less severe conditions (170{degrees}C and 30 atm) than the conventional Ni catalysts (270{degrees}C and 180 atm). Bechtel has performed an extensive cost analysis which shows that Eastman`s propionate synthesis step is competitive with other technologies to produce the anhydride. In the second step, RTI and Eastman have developed active and stable V-Si-P ternary metal oxide catalysts Nb/SiO{sub 2} and Ta/SiO{sub 2} catalysts for the condensation of propionic anhydride and acid with formaldehyde. RTI has demonstrated a novel correlation among the catalyst acid-base properties, condensation reaction yield, and long-term catalyst activity. Current research focuses on enhancing the condensation reaction yields by better understanding of the acid-base property correlation, in situ condensation in a high-temperature, high- pressure (HTHP) slurry reactor, and alternate formaldehyde feedstocks. Based on Eastman and RTI laboratory data, a cost estimate is also being developed for the integrated process.

  2. Methacrylated gelatin and mature adipocytes are promising components for adipose tissue engineering.

    PubMed

    Huber, Birgit; Borchers, Kirsten; Tovar, Günter Em; Kluger, Petra J

    2016-01-01

    In vitro engineering of autologous fatty tissue constructs is still a major challenge for the treatment of congenital deformities, tumor resections or high-graded burns. In this study, we evaluated the suitability of photo-crosslinkable methacrylated gelatin (GM) and mature adipocytes as components for the composition of three-dimensional fatty tissue constructs. Cytocompatibility evaluations of the GM and the photoinitiator Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) showed no cytotoxicity in the relevant range of concentrations. Matrix stiffness of cell-laden hydrogels was adjusted to native fatty tissue by tuning the degree of crosslinking and was shown to be comparable to that of native fatty tissue. Mature adipocytes were then cultured for 14 days within the GM resulting in a fatty tissue construct loaded with viable cells expressing cell markers perilipin A and laminin. This work demonstrates that mature adipocytes are a highly valuable cell source for the composition of fatty tissue equivalents in vitro. Photo-crosslinkable methacrylated gelatin is an excellent tissue scaffold and a promising bioink for new printing techniques due to its biocompatibility and tunable properties.

  3. Syringyl Methacrylate, a Hardwood Lignin-Based Monomer for High-Tg Polymeric Materials

    PubMed Central

    2016-01-01

    As viable precursors to a diverse array of macromolecules, biomass-derived compounds must impart wide-ranging and precisely controllable properties to polymers. Herein, we report the synthesis and subsequent reversible addition–fragmentation chain-transfer polymerization of a new monomer, syringyl methacrylate (SM, 2,6-dimethoxyphenyl methacrylate), that can facilitate widespread property manipulations in macromolecules. Homopolymers and heteropolymers synthesized from SM and related monomers have broadly tunable and highly controllable glass transition temperatures ranging from 114 to 205 °C and zero-shear viscosities ranging from ∼0.2 kPa·s to ∼17,000 kPa·s at 220 °C, with consistent thermal stabilities. The tailorability of these properties is facilitated by the controlled polymerization kinetics of SM and the fact that one vs two o-methoxy groups negligibly affect monomer reactivity. Moreover, syringol, the precursor to SM, is an abundant component of depolymerized hardwood (e.g., oak) and graminaceous (e.g., switchgrass) lignins, making SM a potentially sustainable and low-cost candidate for tailoring macromolecular properties. PMID:27213117

  4. Radiation induced graft copolymerization of methyl methacrylate onto chrome-tanned pig skins

    NASA Astrophysics Data System (ADS)

    Pietrucha, K.; Pȩkala, W.; Kroh, J.

    Graft copolymerization of methyl methacrylate (MMA) onto chrome-tanned pig skins was carried out by the irradiation with 60Co ?-rays. The grafted polymethyl methacrylate (PMMA) chains were isolated by acid hydrolysis of the collagen backbone in order to characterize the graft copolymers. Proof of grafting was obtained through the detection of amino acid endgroups in the isolated grafts by reaction with ninhydrin. The grafting yield of MMA in aqueous emulsion was found to be higher than that for pure MMA and MMA in acetone. The degree of grafting increases with increasing monomer concentration in emulsion and reaches maximum at radiation dose ca 15 kGy. The yield of grafting is very high - ca 90% of monomer converts into copolymer and only 10% is converted into homopolymer. The present paper reports the physical properties of chrome-tanned pig skins after graft polymerization with MMA in emulsion. Modified leathers are more resistant against water absorption and abrasion in comparison with unmodified ones. They have more uniform structure over the whole surface, greater thickness and stiffness. The results reported seem to indicate that MMA may be used in the production of shoe upper and sole leathers. The mechanism of some of the processes occuring during radiation grafting of MMA in water emulsion on tanned leathers has been also suggested and discussed.

  5. Exposure assessment of acrylates/methacrylates in radiation-cured applications

    SciTech Connect

    Not Available

    1987-09-25

    Occupational exposures to radiation-cured acrylates/methacrylates during their processing and use in coatings, inks, and adhesives were evaluated in 12 walk-through surveys at formulator and applicator sites. Inhalation and dermal-exposure routes were studied. According to the authors, the basic process used to formulate coatings, inks, and adhesives consists of blending raw materials in closed mixing vessels using local exhaust ventilation in the form of elephant trunks at vessel charging and packaging locations. Application methods surveyed included reverse-roll coaters, direct roll coaters, curtain/rain coaters, laminators, pneumatic injection, spray guns, and manual application. At the sites surveyed, the number of workers potentially exposed at each site ranged from two to 142. Process operators at applicator sites had the greatest potential for dermal exposure. Generally, the potential for inhalation exposure was low due to low volatility of the multifunctional acrylates/methacrylates used in the formulations. No reliable air-monitoring data were available at any site. Respirator use was limited and sporadic.

  6. Engineered Contractile Skeletal Muscle Tissue on a Microgrooved Methacrylated Gelatin Substrate

    PubMed Central

    Hosseini, Vahid; Ahadian, Samad; Ostrovidov, Serge; Camci-Unal, Gulden; Chen, Song; Kaji, Hirokazu; Ramalingam, Murugan

    2012-01-01

    To engineer tissue-like structures, cells must organize themselves into three-dimensional (3D) networks that mimic the native tissue microarchitecture. Microfabricated hydrogel substrates provide a potentially useful platform for directing cells into biomimetic tissue architecture in vitro. Here, we present microgrooved methacrylated gelatin hydrogels as a suitable platform to build muscle-like fibrous structures in a facile and highly reproducible fashion. Microgrooved hydrogel substrates with two different ridge sizes (50 and 100 μm) were fabricated to assess the effect of the distance between engineered myofibers on the orientation of the bridging C2C12 myoblasts and the formation of the resulting multinucleated myotubes. It was shown that although the ridge size did not significantly affect the C2C12 myoblast alignment, the wider-ridged micropatterned hydrogels generated more myotubes that were not aligned to the groove direction as compared to those on the smaller-ridge micropatterns. We also demonstrated that electrical stimulation improved the myoblast alignment and increased the diameter of the resulting myotubes. By using the microstructured methacrylated gelatin substrates, we built free-standing 3D muscle sheets, which contracted when electrically stimulated. Given their robust contractility and biomimetic microarchitecture, engineered tissues may find use in tissue engineering, biological studies, high-throughput drug screening, and biorobotics. PMID:22963391

  7. Transdermal regulation of vascular network bioengineering using a photopolymerizable methacrylated gelatin hydrogel.

    PubMed

    Lin, Ruei-Zeng; Chen, Ying-Chieh; Moreno-Luna, Rafael; Khademhosseini, Ali; Melero-Martin, Juan M

    2013-09-01

    The search for hydrogel materials compatible with vascular morphogenesis is an active area of investigation in tissue engineering. One candidate material is methacrylated gelatin (GelMA), a UV-photocrosslinkable hydrogel that is synthesized by adding methacrylate groups to the amine-containing side-groups of gelatin. GelMA hydrogels containing human endothelial colony-forming cells (ECFCs) and mesenchymal stem cells (MSCs) can be photopolymerized ex vivo and then surgically transplanted in vivo as a means to generate vascular networks. However, the full clinical potential of GelMA will be best captured by enabling minimally invasive implantation and in situ polymerization. In this study, we demonstrated the feasibility of bioengineering human vascular networks inside GelMA constructs that were first subcutaneously injected into immunodeficient mice while in liquid form, and then rapidly crosslinked via transdermal exposure to UV light. These bioengineered vascular networks developed within 7 days, formed functional anastomoses with the host vasculature, and were uniformly distributed throughout the constructs. Most notably, we demonstrated that the vascularization process can be directly modulated by adjusting the initial exposure time to UV light (15-45 s range), with constructs displaying progressively less vascular density and smaller average lumen size as the degree of GelMA crosslinking was increased. Our studies support the use of GelMA in its injectable form, followed by in situ transdermal photopolymerization, as a preferable means to deliver cells in applications that require the formation of vascular networks in vivo.

  8. Transdermal regulation of vascular network bioengineering using a photopolymerizable methacrylated gelatin hydrogel

    PubMed Central

    Lin, Ruei-Zeng; Chen, Ying-Chieh; Moreno-Luna, Rafael; Khademhosseini, Ali; Melero-Martin, Juan M.

    2013-01-01

    The search for hydrogel materials compatible with vascular morphogenesis is an active area of investigation in tissue engineering. One candidate material is methacrylated gelatin (GelMA), a UV-photocrosslinkable hydrogel that is synthesized by adding methacrylate groups to the amine-containing side-groups of gelatin. GelMA hydrogels containing human endothelial colony-forming cells (ECFCs) and mesenchymal stem cells (MSCs) can be photopolymerized ex vivo and then surgically transplanted in vivo as a means to generate vascular networks. However, the full clinical potential of GelMA will be best captured by enabling minimally invasive implantation and in situ polymerization. In this study, we demonstrated the feasibility of bioengineering human vascular networks inside GelMA constructs that were first subcutaneously injected into immunodeficient mice while in liquid form, and then rapidly crosslinked via transdermal exposure to UV light. These bioengineered vascular networks developed within 7 days, formed functional anastomoses with the host vasculature, and were uniformly distributed throughout the constructs. Most notably, we demonstrated that the vascularization process can be directly modulated by adjusting the initial exposure time to UV light (15–45 s range), with constructs displaying progressively less vascular density and smaller average lumen size as the degree of GelMA crosslinking was increased. Our studies support the use of GelMA in its injectable form, followed by in situ transdermal photopolymerization, as a preferable means to deliver cells in applications that require the formation of vascular networks in vivo. PMID:23773819

  9. Effects of Dental Methacrylates on Oxygen Consumption and Redox Status of Human Pulp Cells

    PubMed Central

    Nocca, Giuseppina; Callà, Cinzia; Martorana, Giuseppe Ettore; Cicillini, Loredana; Lupi, Alessandro; Cordaro, Massimo; Luisa Gozzo, Maria

    2014-01-01

    Several studies have already demonstrated that the incomplete polymerization of resin-based dental materials causes the release of monomers which might affect cell metabolism. The aim of this study was to investigate the effects of triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, urethane dimethacrylate, and 2-hydroxyethyl methacrylate on (1) cellular energy metabolism, evaluating oxygen consumption rate, glucose consumption, glucose 6-phosphate dehydrogenase activity, and lactate production, and (2) cellular redox status, through the evaluation of glutathione concentration and of the activities of enzymes regulating glutathione metabolism. Methods. Human pulp cells were used and oxygen consumption was measured by means of a Clark electrode. Moreover, reactive oxygen species production was quantified. Enzymatic activity and glucose and lactate concentrations were determined through a specific kit. Results. Triethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, and 2-hydroxyethyl methacrylate induced a decrease in oxygen consumption rate, an enhancement of glucose consumption, and lactate production, whilst glucose 6-phosphate dehydrogenase and glutathione reductase activity were not significantly modified. Moreover, the monomers induced an increase of reactive oxygen species production with a consequent increase of superoxide dismutase and catalase enzymatic activities. A depletion of both reduced and total glutathione was also observed. Conclusion. The obtained results indicate that dental monomers might alter energy metabolism and glutathione redox balance in human pulp cells. PMID:24693541

  10. Visible Light Crosslinking of Methacrylated Hyaluronan Hydrogels for Injectable Tissue Repair

    PubMed Central

    Fenn, Spencer L.; Oldinski, Rachael A.

    2015-01-01

    Tissue engineering hydrogels are primarily cured in situ using ultraviolet (UV) radiation which limits the use of hydrogels as drug or cell carriers. Visible green light activated crosslinking systems are presented as a safe alternative to UV photocrosslinked hydrogels, without compromising material properties such as viscosity and stiffness. The objective of this study was to fabricate and characterize photocrosslinked hydrogels with well-regulated gelation kinetics and mechanical properties for the repair or replacement of soft tissue. An anhydrous methacrylation of hyaluronan (HA) was performed to control the degree of modification (DOM) of HA, verified by 1H-NMR spectroscopy. UV activated crosslinking was compared to visible green light activated crosslinking. While the different photocrosslinking techniques resulted in varied crosslinking times, comparable mechanical properties of UV and green light activated crosslinked hydrogels were achieved using each photocrosslinking method by adjusting time of light exposure. Methacrylated HA (HA-MA) hydrogels of varying molecular weight, DOM and concentration exhibited compressive moduli ranging from 1 kPa to 116 kPa, for UV crosslinking, and 3 kPa to 146 kPa, for green light crosslinking. HA-MA molecular weight and concentration were found to significantly influence moduli values. HA-MA hydrogels did not exhibit any significant cytotoxic affects towards human mesenchymal stem cells. Green light activated crosslinking systems are presented as a viable method to form natural-based hydrogels in situ. PMID:26097172

  11. Styrene-butadiene rubber/halloysite nanotubes nanocomposites modified by methacrylic acid

    NASA Astrophysics Data System (ADS)

    Guo, Baochun; Lei, Yanda; Chen, Feng; Liu, Xiaoliang; Du, Mingliang; Jia, Demin

    2008-12-01

    Methacrylic acid (MAA) was used to improve the performance of styrene-butadiene rubber (SBR)/halloysite nanotubes (HNTs) nanocomposites by direct blending. The detailed interaction mechanisms of MAA and the in situ formed zinc methacrylate (ZDMA) were revealed by X-ray diffraction (XRD), surface area and porosity analysis, X-ray photoelectron spectroscopy (XPS) together with crosslink density determination. The strong interfacial bonding between HNTs and rubber matrix is resulted through ZDMA and MAA intermediated linkages. ZDMA connects SBR and HNTs via grafting/complexation mechanism. MAA bonds SBR and HNTs through grafting/hydrogen bonding mechanism. Significantly improved dispersion of HNTs in virtue of the interactions between HNTs and MAA or ZDMA was achieved. Effects of MAA content on the vulcanization behavior, morphology and mechanical properties of the nanocomposites were investigated. Promising mechanical properties of MAA modified SBR/HNTs nanocomposites were obtained. The changes in vulcanization behavior, mechanical properties and morphology were correlated with the interactions between HNTs and MAA or ZDMA and the largely improved dispersion of HNTs.

  12. Methacrylated gelatin and mature adipocytes are promising components for adipose tissue engineering.

    PubMed

    Huber, Birgit; Borchers, Kirsten; Tovar, Günter Em; Kluger, Petra J

    2016-01-01

    In vitro engineering of autologous fatty tissue constructs is still a major challenge for the treatment of congenital deformities, tumor resections or high-graded burns. In this study, we evaluated the suitability of photo-crosslinkable methacrylated gelatin (GM) and mature adipocytes as components for the composition of three-dimensional fatty tissue constructs. Cytocompatibility evaluations of the GM and the photoinitiator Lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP) showed no cytotoxicity in the relevant range of concentrations. Matrix stiffness of cell-laden hydrogels was adjusted to native fatty tissue by tuning the degree of crosslinking and was shown to be comparable to that of native fatty tissue. Mature adipocytes were then cultured for 14 days within the GM resulting in a fatty tissue construct loaded with viable cells expressing cell markers perilipin A and laminin. This work demonstrates that mature adipocytes are a highly valuable cell source for the composition of fatty tissue equivalents in vitro. Photo-crosslinkable methacrylated gelatin is an excellent tissue scaffold and a promising bioink for new printing techniques due to its biocompatibility and tunable properties. PMID:26017717

  13. Poly(ethylene glycol) methacrylate hydrolyzable microspheres for transient vascular embolization.

    PubMed

    Louguet, Stéphanie; Verret, Valentin; Bédouet, Laurent; Servais, Emeline; Pascale, Florentina; Wassef, Michel; Labarre, Denis; Laurent, Alexandre; Moine, Laurence

    2014-03-01

    Poly(ethylene glycol) methacrylate (PEGMA) hydrolyzable microspheres intended for biomedical applications were readily prepared from poly(lactide-co-glycolide) (PLGA)-poly(ethylene glycol) (PEG)-PLGA crosslinker and PEGMA as a monomer using a suspension polymerization process. Additional co-monomers, methacrylic acid and 2-methylene-1,3-dioxepane (MDO), were incorporated into the initial formulation to improve the properties of the microspheres. All synthesized microspheres were spherical in shape, calibrated in the 300-500 μm range, swelled in phosphate-buffered saline (PBS) and easily injectable through a microcatheter. Hydrolytic degradation experiments performed in PBS at 37 °C showed that all of the formulations tested were totally degraded in less than 2 days. The resulting degradation products were a mixture of low-molecular-weight compounds (PEG, lactic and glycolic acids) and water-soluble polymethacrylate chains having molecular weights below the threshold for renal filtration of 50 kg mol(-1) for the microspheres containing MDO. Both the microspheres and the degradation products were determined to exhibit minimal cytotoxicity against L929 fibroblasts. Additionally, in vivo implantation in a subcutaneous rabbit model supported the in vitro results of a rapid degradation rate of microspheres and provided only a mild and transient inflammatory reaction comparable to that of the control group. PMID:24321348

  14. Morphological characterization of silica obtained by calcination of methacrylic and epoxy - silica hybrid systems

    NASA Astrophysics Data System (ADS)

    Tescione, F.; Lionetto, F.; Corcione, C. Esposito; Buonocore, G. G.; Striani, R.; Lavorgna, M.; Frigione, M.

    2016-05-01

    The work is addressed to investigating the potentiality of calcination of organic-inorganic (O-I) hybrids as a feasible approach to produce silica particles, at mild temperature conditions and with tailored morphology. Two different innovative hybrid systems were obtained through sol-gel process with a siloxane content ranging from 6 to 26wt%. The two O-I hybrids differed for i) the organic matrix (methacrylic or epoxy), ii) its crosslinking mechanism (photopolymerization for methacrylic systems or thermal cold-cure for epoxy systems) and iii) the rate ratio between sol-gel and crosslinking reactions. Different characterization techniques were used to understand the effect of composition and curing method on the morphology of the silica obtained from O-I hybrids after calcination in air. The results confirm the morphology and properties of silica particles in terms of surface and porosity may be tailored over a wide range by varying the composition and nature of organic and inorganic precursors of hybrids.

  15. Determination of methacrylic acid in food simulants by pyrolytic butylation-gas chromatography.

    PubMed

    Huang, Zhongping; Qiu, Ruofeng; Liu, Tingfei; Huang, Yilei; Zhu, Zuoyi; Wang, Lili

    2016-07-01

    An on-line pyrolytic butylation approach was proposed to determine methacrylic acid (MA) in food simulants by gas chromatography (GC) without an expensive pyrolyzer. MA in food simulants was converted into butyl methacrylate in the presence of tetrabutylammonium hydroxide (TBAH) without any pretreatment at 330°C in the injection-port, contributing to high GC signal response. The derivatizing conditions for the proposed method were optimized, namely the injection-port temperature, type and amount of the organic alkaline used for derivatization. A series of standard solutions of MA in the range of 1.0-50mg/kg were analyzed with correlation coefficient r≥0.9975. The limits of detection (LODs) were less than 0.15mg/kg for MA in four matrix simulants (distilled water, 3%w/v acetic acid, 10%v/v ethanol, and isooctane). Relative standard deviations (RSDs) for retention time, peak height and peak area were all less than 3.88%. The technique was successfully applied to the analysis of MA migrating from plastic cup samples, with recoveries of added MA in the range of 96.5-123.0%. Direct injection of the simulants into the GC system after migration tests, without any pretreatment step, makes the developed method of great value for rapid screening analysis of samples in bulks. PMID:27262371

  16. Low-cost fabrication of poly(methyl methacrylate) microchips using disposable gelatin gel templates.

    PubMed

    Chen, Zhi; Yu, Zhengyin; Chen, Gang

    2010-06-15

    A simple method based on disposable gelatin gel templates has been developed for the low-cost fabrication of poly(methyl methacrylate) (PMMA) microfluidic chips. Gelatin was dissolved in glycerol aqueous solution under heat to prepare a thermally reversible impression material. The molten gel was then sandwiched between a glass plate and a SU-8 template bearing negative relief of microstructure. After cooling, the negative SU-8 template could be easily separated from the solidified gelatin gel and a layer of gelatin template bearing positive relief of the microstructure was left on the glass plate. Subsequently, prepolymerized methyl methacrylate molding solution containing a UV-initiator was sandwiched between the gel template and a PMMA plate and was allowed to polymerize under UV light to fabricate PMMA channel plate at room temperature. Complete microchips could be obtained by bonding the channel plates with covers using plasticizer-assisted thermal bonding at 90 degrees C. Gelatin gel template can be mass-produced and will find application in the mass production of PMMA microchips at low cost. The prepared microfluidic microchips have been successfully employed in the capillary electrophoresis analysis of several ions in connection with contactless conductivity detection.

  17. Effects of star-shape poly(alkyl methacrylate) arm uniformity on lubricant properties

    DOE PAGES

    Robinson, Joshua W.; Qu, Jun; Erck, Robert; Cosimbescu, Lelia; Zhou, Yan

    2016-03-29

    Star-shaped poly(alkyl methacrylate)s (PAMAs) were prepared and blended into an additive-free engine oil to assess the structure property relationship between macromolecular structure and lubricant performance. These additives were designed with a comparable number of repeating units per arm and the number of arms was varied between 3 and 6. Well-defined star-shaped PAMAs were synthesized by atom transfer radical polymerization (ATRP) via a core-first strategy from multi-functional headgroups. Observations of the polymer-oil blends suggest that stars with less than four arms are favorable as a viscosity index improver (VII), and molecular weight dominates viscosity-related effects over other structural features. Star-shaped PAMAs,more » as oil additives, effectively reduce the friction coefficient in both mixed and boundary lubrication regime. Several analogs outperformed commercial VIIs in both viscosity and friction performance. Furthermore, increased wear rates were observed for these star-shaped PAMAs in the boundary lubrication regime suggesting pressure-sensitive conformations may exist.« less

  18. Bond Strengths of Silorane- and Methacrylate-Based Composites to Various Underlying Materials

    PubMed Central

    Ozer, Sezin; Sen Tunc, Emine; Gonulol, Nihan

    2014-01-01

    Objective. To evaluate shear bond strength (SBS) values of a methacrylate (FZ 250) and a silorane-based (FS) resin composite to various underlying materials. Materials and Methods. A total of 80 samples were prepared with four different underlying materials; a flowable (FLC) and a bulk-fill flowable composite (BFC), and a conventional (CGIC) and resin modified glass-ionomer cement (RMGIC). These underlying materials were laminated plus to methacrylate or silorane-based resin composites (n = 10). To evaluate the specimens SBS values were evaluated with a universal testing machine (cross-head speed; 1.0 mm/min). Statistical comparisons were carried out using two-way ANOVA and Tukey's post hoc test with a significance level of P < 0.05. Results. SBS values for FZ250 were significantly higher than for FS for all of the underlying materials tested (P < 0.05). SBS values of FZ250 to BFC were significantly higher than to all other materials (P < 0.05), whereas SBS values of FS did not vary significantly according to underlying material (P > 0.05). Conclusion. The use of FS in conjunction with any of the tested materials showed lower SBS than the FZ 250. Also, new low elastic modulus liner BFC presented slightly good interfacial adhesion so, the usage of BFC as an underlying material may be preferable for FZ 250. PMID:24895608

  19. Semi-micro reversed-phase liquid chromatography for the separation of alkyl benzenes and proteins exploiting methacrylate- and polystyrene-based monolithic columns.

    PubMed

    Masini, Jorge Cesar

    2016-05-01

    Monolithic columns were synthesized inside 1.02 mm internal diameter fused-silica lined stainless-steel tubing. Styrene and butyl, hexyl, lauryl, and glycidyl methacrylates were the functional monomers. Ethylene glycol dimethacrylate and divinylbenzene were the crosslinkers. The glycidyl methacrylate polymer was modified with gold nanoparticles and dodecanethiol (C12 ). The separation of alkylbenzenes was investigated by isocratic elution in 60:40 v/v acetonitrile/water. The columns based on polystyrene-co-divinylbenzene and poly(glycidyl methacrylate)-co-ethylene glycol dimethacrylate modified with dodecanethiol did not provide any separation of alkyl benzenes. The poly(hexyl methacrylate)-co-ethylene glycol dimethacrylate and poly(lauryl methacrylate)-co-ethylene glycol dimethacrylate columns separated the alkyl benzenes with plate heights between 30 and 60 μm (50 μL min(-1) and 60°C). Similar efficiency was achieved in the poly(butyl methacrylate)-co-ethylene glycol dimethacrylate column, but only at 10 μL min(-1) (0.22 mm s(-1) ). Backpressures varied from 0.38 MPa in the hexyl methacrylate to 13.4 MPa in lauryl methacrylate columns (50 μL min(-1) and 60°C). Separation of proteins was achieved in all columns with different efficiencies. At 100 μL min(-1) and 60°C, the lauryl methacrylate columns provided the best separation, but their low permeability prevented high flow rates. Flow rates up to 500 μL min(-1) were possible in the styrene, butyl and hexyl methacrylate columns.

  20. Effects of temperature and alkyl groups of poly(alkyl methacrylate)s on inter- and intramolecular interactions of excited singlet states of pyrenyl guest molecules.

    PubMed

    Abraham, Shibu; Atvars, Teresa D Z; Weiss, Richard G

    2010-09-30

    Temperature-induced changes in the static and dynamic characteristics of the fluorescence from pyrene and N,N-dimethyl-3-(pyren-1-yl)propan-1-amine (PyC3NMe2) have been used to determine the locations and mobilities of these probes in the anisotropic environments provided by films of 5 poly(alkyl methacrylate) (PAMA) polymers in which alkyl is ethyl, butyl, isobutyl, cyclohexyl, and hexadecyl. Whereas emission from pyrene reports on the polarity of the guest sites and the ability of molecules to diffuse translationally between sites, emission from PyC3NMe2 yields information about the fluidity and the shape of the guest sites. Data have been obtained from 20 to >400 K, a range that spans the onsets of several relaxation processes in the hosts. Those data indicate that the pyrenyl groups reside near to ester functionalities in most of the PAMAs, although the distance from them (and the main chains) depends upon the bulkiness of the alkyl groups. Among the most important conclusions derived from this research is that the rates of segmental relaxation phenomena near the probe molecules--and not free volume, as was concluded previously from fluorescence measurements in polyethylene films--are the dominant contributors to the fluorescence changes. Of practical importance, changes in those rates have permitted the onset temperatures of many of the relaxation phenomena occurring in the vicinity of the probes to be located.

  1. Study of two cohorts of workers exposed to methyl methacrylate in acrylic sheet production

    PubMed Central

    Tomenson, J; Bonner, S; Edwards, J; Pemberton, M; Cummings, T; Paddle, G

    2000-01-01

    OBJECTIVES—To study mortality among 4324 workers at two United Kingdom factories, Darwen, Lancashire and Wilton, Cleveland, producing polymethyl methacrylate (PMMA) sheet. The Darwen factory is still active, but the Wilton one was closed in 1970. Also, to investigate patterns of mortality after exposure to methyl methacrylate; in particular, mortality from colon and rectal cancer.
METHODS—All male employees at the Darwen factory with a record of employment in 1949-88 and all men ever employed at the Wilton factory (1949-70) were investigated. The vital status of both cohorts was ascertained on 31 December 1995. The exposure of 1526 subjects at the Darwen plant who were engaged from 1949 onwards could be characterised. The mean duration of exposure was 7.6 years at 13.2 ppm (8 hour time weighted average), although exposures in some work groups were as high as 100 ppm. It was not possible to calculate the cumulative exposure of workers first employed at the Darwen plant before 1949 or workers at the Wilton factory.
RESULTS—In the Darwen cohort, 622 deaths were identified and a further 700 deaths in the Wilton cohort. Mortalities for the cohort were compared with national and local rates and expressed as standardised mortality ratios (SMRs). In the subcohort of Darwen workers with more than minimal exposure to MMA, reduced mortalities compared with national and local rates, were found for all causes (SMR 94), and colorectal cancer (SMR 92), but mortality from all cancers was slightly increased (SMR 104). No relations were found with cumulative exposure to MMA. In the subcohort of Wilton workers, mortality from all causes of death was significantly reduced (SMR 89), but mortality from all cancers (SMR 103) and colorectal cancer (SMR 124) were increased. The excess of colorectal cancer was confined to employees with less than 1 year of employment.
CONCLUSION—The study provided no clear evidence that employment at the factories or exposure to

  2. On the degelation of networks - Case of the radiochemical degradation of methyl methacrylate - ethylene glycol dimethacrylate copolymers

    NASA Astrophysics Data System (ADS)

    Richaud, Emmanuel; Gilormini, Pierre; Verdu, Jacques

    2016-05-01

    Methyl methacrylate networks were synthetized and submitted to radiochemical degradation. Ageing was monitored by means of sol-gel analysis and glass transition temperature measurements. Networks were shown to undergo exclusively chain scission process leading to the degelation of network. The critical conversion degree corresponding to degelation (loss of all elastically active chains) is discussed regarding a statistical theory.

  3. Study of the sequential conversion of citric to itaconic to methacrylic acid in near-critical and supercritical water

    SciTech Connect

    Carlsson, M.; Habenicht, C.; Kam, L.C.; Antal, M.J. Jr. ); Bian, N.; Cunningham, R.J.; Jones, M. Jr. . Dept. of Chemistry)

    1994-08-01

    Between 200 and 400 million lb of citric acid are produced annually in the USA by fermentation of molasses and other sugars using the microorganism Aspergillus niger. A lesser quantity of itaconic acid is manufactured by a similar technology using Aspergillus terreus. The recovery of citric acid from its fermentation broth via calcium salt precipitation is a costly, highly complex, sophisticated operation. USDOE estimates the cost of dry citric acid produced from a new plant to be about $0.59/lb, whereas the estimated cost of wet citric acid (in its fermentation broth) from a new plant is about $0.19/lb and from an old plant is about $0.15/lb. Citric acid rapidly reacts in hot (250 C), compressed (34.5 MPa) liquid water to form itaconic and citraconic acids with a combined selectivity that exceeds 90%. At higher temperatures (360 C), in the absence and presence of NaOH, itaconic acid decarboxylates to form methacrylic acid. The yield of methacrylic acid depends on the temperature, pH, and buffer strength of the medium, reaching a maximum of about 70% (by mole) of the itaconic acid feed. Conditions which favor the production of methacrylic acid also lead to the formation of its hydration product: hydroxyisobutyric acid. Under optimum conditions the combined yield of methacrylic acid and hydroxyisobutyric acid from itaconic acid exceeds 80%. Results are consistent with well-established dehydration and decarboxylation mechanisms.

  4. Poly(glycidyl methacrylate)-grafted hydrophobic charge-induction agarose resins with 5-aminobenzimidazole as a functional ligand.

    PubMed

    Liu, Tao; Lin, Dong-Qiang; Wang, Cun-Xiang; Yao, Shan-Jing

    2016-08-01

    Hydrophobic charge-induction chromatography is a new technology for antibody purification. To improve antibody adsorption capacity of hydrophobic charge-induction resins, new poly(glycidyl methacrylate)-grafted hydrophobic charge-induction resins with 5-aminobenzimidazole as a functional ligand were prepared. Adsorption isotherms, kinetics, and dynamic binding behaviors of the poly(glycidyl methacrylate)-grafted resins prepared were investigated using human immunoglobulin G as a model protein, and the effects of ligand density were discussed. At the moderate ligand density of 330 μmol/g, the saturated adsorption capacity and equilibrium constant reached the maximum of 140 mg/g and 25 mL/mg, respectively, which were both much higher than that of non-grafted resin with same ligand. In addition, effective pore diffusivity and dynamic binding capacity of human immunoglobulin G onto the poly(glycidyl methacrylate)-grafted resins also reached the maximum at the moderate ligand density of 330 μmol/g. Dynamic binding capacity at 10% breakthrough was as high as 76.3 mg/g when the linear velocity was 300 cm/h. The results indicated that the suitable polymer grafting combined with the control of ligand density would be a powerful tool to improve protein adsorption of resins, and new poly(glycidyl methacrylate)-grafted hydrophobic charge-induction resins have a promising potential for antibody purification applications. PMID:27465269

  5. New Functionalities of PA6,6 Fabric Modified by Atmospheric Pressure Plasma and Grafted Glycidyl Methacrylate Derivatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxidative atmospheric pressure plasma was utilized to activate surface of PA 6,6 fabrics followed by graft copolymerization of glycidyl methacrylate (GMA) and further reacted with triethylene tetramine (TETA), quaternary ammonium chitosan (HTCC) or cyclodextrin (CD). The inner CD cavity was complexe...

  6. Light-curing time and aging effects on the nanomechanical properties of methacrylate- and silorane-based restorations.

    PubMed

    Catelan, A; Pollard, T; Bedran-Russo, Ak; Santos, Ph Dos; Ambrosano, Gmb; Aguiar, Fhb

    2014-01-01

    SUMMARY The aim of this study was to assess the influence of light-curing time on the nanohardness (H) and reduced elastic modulus (Er) of components (underlying dentin, hybrid layer, adhesive, and composite) of methacrylate- and silorane-based restorations after 24 hours and six months of storage. Class II slot preparations were carried out in human molars (n=3) and restored with methacrylate (Clearfil SE Bond [Kuraray] + Filtek Z250 [3M ESPE]) or silorane (LS restorative system [3M ESPE]) restorative systems and light-cured using light-emitting diode at 1390 mW/cm(2) for the recommended manufacturers' time or double time. Restorations were sectioned, and bonded dentin-resin interfaces were embedded in epoxy resin and polished for evaluation with a Berkovich fluid cell tip (TI 700 Ubi-1 nanoindenter, Hysitron). Data were statistically analyzed by analysis of variance and Tukey's test (alpha=0.05). Overall, the H and Er values were higher for methacrylate-based restorations than for silorane materials (p≤0.05), an increase in curing time did not improve the H and Er of the bonded interface components of either material (p>0.05), and aging significantly decreased the mechanical properties of interface components of both resin-based restorative systems (p≤0.05). In general, nanomechanical properties decreased after six months of storage, the methacrylate restorative system exhibited higher H and Er than silorane, and light-curing time did not influence the properties tested.

  7. Enhancing the sensitivity of poly(methyl methacrylate) based optical fiber Bragg grating temperature sensors.

    PubMed

    Zhang, Wei; Webb, David J; Peng, Gang-Ding

    2015-09-01

    In poly(methyl methacrylate) (PMMA)-based optical fiber gratings (POFBGs), the temperature response is determined by thermal expansion and the thermo-optic effect of the fiber. Because thermal expansion introduces a positive change and the thermo-optic effect introduces a negative change in the Bragg wavelength of the POFBG, they cancel out each other to some extent, leading to reduced and varying temperature sensitivity. By pre-straining a POFBG, the contribution of thermal expansion can be removed, and, consequently, the temperature sensitivity of POFBG can be greatly enhanced. Theoretical analysis also indicates a reduced thermo-optic coefficient of POFBG due to restrained linear expansion that matches experimental results. PMID:26368708

  8. Tensile behaviour of blends of poly(vinylidene fluoride) with poly(methyl methacrylate)

    NASA Technical Reports Server (NTRS)

    Cebe, Peggy; Chung, Shirley Y.

    1990-01-01

    Blends of poly(vinylidene fluoride) (PVF2) and poly(methyl methacrylate) (PMMA) were prepared over a wide concentration range and tested in tension at the same relative temperature below the glass transition. In nearly all blends, under conditions favoring disentanglement, (decrease in strain rate, or increase in test temperature), the yield stress and drawing stress decreased while the breaking strain increased. For materials with about the same degree of crystallinity, those with a higher proportion of amorphous PVF2 exhibited brittle-like behavior as a result of interlamellar tie molecules. In the semicrystalline blends, yield stress remains high as the test temperature approaches Tg, whereas in the amorphous blends the yield stress falls to zero near Tg. Results of physical aging support the role of interlamellar ties which cause semicrystalline blends to exhibit aging at temperatures above Tg.

  9. Fabrication of carbohydrate microarrays on a poly(2-hydroxyethyl methacrylate)-based photoactive substrate.

    PubMed

    Sundhoro, Madanodaya; Wang, Hui; Boiko, Scott T; Chen, Xuan; Jayawardena, H Surangi N; Park, JaeHyeung; Yan, Mingdi

    2016-01-21

    We report the fabrication of carbohydrate microarrays on a photoactive polymer, poly(HEMA-co-HEMA-PFPA), synthesized by RAFT copolymerization of 2-hydroxyethyl methacrylate (HEMA) and perfluorophenyl azide (PFPA)-derivatized HEMA (HEMA-PFPA). PFPA allows the covalent immobilization of carbohydrates whereas the HEMA polymer provides an antifouling surface, thus the microarrays can be used directly without pretreating the array with a blocking agent. The microarrays were prepared by spin-coating the polymer followed by printing the carbohydrates. Subsequent irradiation simultaneously immobilized the carbohydrates and crosslinked the polymer matrix. The obtained 3D carbohydrate microarrays showed enhanced fluorescence signals upon treating with a fluorescent lectin in comparison with a 2D microarray. The signals were acquired at a lower lectin concentration and a shorter incubation time. When treated with E. coli bacteria, the carbohydrate microarray showed results that were consistent with their binding patterns. PMID:26646384

  10. Acoustic and ultrasonic characterization constraints of self-healing (ethylene-co-methacrylic acid) copolymers

    NASA Astrophysics Data System (ADS)

    Pestka, Kenneth, II; Buckley, Jonathan; Kalista, Stephen; Bowers, Nicholas

    Recent experiments indicate that small sample poly (ethylene-co-methacrylic acid) copolymers (EMAA copolymers) exhibit time dependent variation in their acoustic and ultrasonic resonant spectra after exposure to a damage event. However, due to the relatively soft nature of these thermoplastic materials, several experimental constraints affect efficacy of resonant spectral analysis. In this work we will the address the effect of several characterization constraints on a self-healing EMAA ionomer (commercially known as Dupont Surlyn 8920) including the effects of transducer loading, continuous rapid resonant excitation and temporally separated long-term resonant excitation. In some circumstances, these experimental constraints can influence the time dependence of sample resonant frequency evolution, quality factor, and variation in spectral waveform. By quantifying these effects, robust characterization of post-damage self-healing EMAA samples is possible and will be presented.

  11. Self-Diffusion of Poly(isobutyl methacrylate) in Thin Films

    NASA Astrophysics Data System (ADS)

    Katzenstein, Joshua; Janes, Dustin; Hocker, Haley; Chandler, Justin; Ellison, Christopher

    2013-03-01

    While relevant to a variety of applications, such as nanocomposite intercalation and molecular transfer printing, the diffusion of polymers parallel to their confining interfaces has received limited experimental attention to date. A refinement of fluorescence recovery after patterned photobleaching (FRAPP) has been developed by our group as a versatile platform for understanding nanoconfined diffusion. Poly(isobutyl methacrylate) (PiBMA) is an ideal candidate for these studies because (in quartz or silicon wafer supported thin films) it exhibits a film thickness independent glass transition temperature (Tg). This is important because, according to the Rouse model, the diffusion coefficient does not depend simply on the absolute temperature, but on the distance from Tg. Therefore, in our systems the origin of the diffusion coefficient is possibly decoupled from Tg changes that are present in other polymer systems. In this talk, the effect of a variety of parameters, such as film thickness, diffusion temperature, and confining interfaces, will be discussed.

  12. Development of an anthropomorphic head phantom using dolomite and polymethyl methacrylate for dosimetry in computed tomography

    NASA Astrophysics Data System (ADS)

    Ximenes, R. E.; Silva, A.; Balbino, D.; Poletti, M. E.; Maia, A. F.

    2015-12-01

    A real human skull was selected to be a mold for the construction of an anthropomorphic head phantom with a mixture of dolomite and polymethyl methacrylate (PMMA). Using linear attenuation coefficients, we show that it is possible to use dolomite as a bone simulator as long as the proportion of the mixture is 1:1. Acrylic tubes were placed in the phantom constructed to enable the insertion of the ionization chamber to estimate the effective dose. Values for a typical head computed tomography examination found in the literature vary from 0.9 to 4.0 mSv. Dosimetric studies showed that the effective dose for the anthropomorphic phantom was (2.70±0.03) mSv and for the geometric PMMA phantom (3.67±0.04) mSv, values which are in agreement with the intervals reported in the literature. The investment to produce the phantom was approximately US160.00.

  13. Network formation of nanofibrillated cellulose in solution blended poly(methyl methacrylate) composites.

    PubMed

    Littunen, Kuisma; Hippi, Ulla; Saarinen, Tapio; Seppälä, Jukka

    2013-01-01

    Composites of poly(methyl methacrylate) (PMMA) and nanofibrillated cellulose (NFC) were prepared by solution blending and further processed by injection and compression molding. To improve adhesion at the PMMA/NFC interface, the nanofibrils were covalently grafted with PMMA. Formation of a percolating nanofibril network was observed between 1 and 5 wt.% of NFC by dynamic rotational rheometry in molten state. This observation was further supported by the behavior of glass transition temperature which decreased at low NFC concentrations but recovered above the percolation threshold, indicating a decreased mobility of the matrix polymer. This effect was more pronounced with ungrafted NFC, possibly due to a stronger network. The unmodified NFC induced a minor degradation of the molar mass of PMMA. As thin plates, the composites were transparent at low NFC concentrations but became partially aggregated at the highest NFC concentrations. Despite the continuous NFC network, tensile testing showed no improvement of the mechanical properties.

  14. Synthesis, characterization and molecular dynamic simulation on dendronized poly(diphtalimidoalky phenyl) methacrylates

    NASA Astrophysics Data System (ADS)

    Radić, D.; Alegría, L.; Sandoval, C.; Gargallo, L.

    2012-07-01

    Dendronized methacrylates containing 3,5-diphtalimido alkylphenyl moieties with ethyl (M-EthylG1), propyl (M-PropylG1) and butyl (M-ButylG1) spacer groups were synthesized. Monomers of the first generation were polymerized by radical polymerization using AIBN as initiator. The corresponding polymers (P-EthylG1), (P-PropylG1) and (P-ButylG1) were obtained. Monomers and polymers were characterized by 1H-NMR, 13C-NMR, FTIR spectroscopic measurements. Molecular weight was estimated by following the nitrogen content in the obtained polymers. Molecular Dynamic Simulation (MDS) was performed in order to evaluate the radius of gyration (Rg) and the end-to-end distance (ree) to estimate the stiffness of the backbone and of the dendrimers. According to the conformational analysis it is possible to observe different spacial arrangements depending on the length of the spacer group.

  15. Direct measurements of the mechanical strength of carbon nanotube-poly(methyl methacrylate) interfaces.

    PubMed

    Chen, Xiaoming; Zheng, Meng; Park, Cheol; Ke, Changhong

    2013-10-11

    Understanding the interfacial stress transfer between carbon nanotubes (CNTs) and polymer matrices is of great importance to the development of CNT-reinforced polymer nanocomposites. In this paper, an experimental study is presented of the interfacial strength between individual double-walled CNTs and poly(methyl methacrylate) (PMMA) using an in situ nanomechanical single-tube pull-out testing scheme inside a high-resolution electron microscope. By pulling out individual tubes with different embedded lengths, this work reveals the shear lag effect on the nanotube-polymer interface and demonstrates that the effective interfacial load transfer occurs only within a certain embedded length. These results show that the CNT-PMMA interface possesses an interfacial fracture energy within 0.054-0.80 J/m(2) and a maximum interfacial strength within 85-372 MPa. This work is useful to better understand the local stress transfer on nanotube-polymer interfaces. PMID:23606544

  16. Phase Behavior of Star-shaped polystyrene-block-poly(methyl methacrylate) Copolymers

    NASA Astrophysics Data System (ADS)

    Jang, Sangshin; Moon, Hongchul; Lee, Youngmin; Kim, Jin Kon

    2012-02-01

    Star-shaped polystyrene-block-poly(methyl methacrylate) copolymer (PS-b-PMMA) was synthesized by utilizing α-cyclodextrin (α-CD) as a junction point of the star-shaped block copolymer. Eighteen hydroxyl groups on α-CD were substituted with bromine by the reaction with α-bromoisobutyryl bromide for atom transfer radical polymerization. We found that the number of bromine substituted arms per one α-CD was higher than 16 measured by nuclear magnetic resonance and Matrix-assisted laser desorption/ionization. We could control molecular weight of this unusual kind of block copolymer depending on polymerization times. Those polymers were characterized by gel permeation chromatography and nuclear magnetic resonance. Phase behavior of these star-shaped block copolymers were investigated.

  17. Phase behavior of multi-arm star-shaped polystyrene-block-poly(methyl methacrylate) copolymer

    NASA Astrophysics Data System (ADS)

    Jang, Sangshin; Moon, Hong Chul; Bae, Dusik; Kwak, Jonghen; Kim, Jin Kon

    2013-03-01

    We synthesized star-shaped polystyrene-block-poly(methyl methacrylate) copolymer (PS- b-PMMA) by utilizing α-cyclodextrin (α-CD) as a core of the star-shaped block copolymer. Eighteen hydroxyl groups on α-CD were transformed to bromine by the reaction with α-bromoisobutyryl bromide. We found that the number of bromine substituted arms per one α-CD was higher than 16, which was determined by nuclear magnetic resonance and Matrix-assisted laser desorption/ionization. We could control molecular weight of block copolymers by changing polymerization times. The block copolymers were characterized by gel permeation chromatography and nuclear magnetic resonance. Phase behaviors of these star-shaped block copolymers were investigated by small angle X-ray scattering and transmission electron microscopy.

  18. Evaluation of Bone Regeneration on Polyhydroxyethyl-polymethyl Methacrylate Membrane in a Rabbit Calvarial Defect Model.

    PubMed

    Kim, Somin; Hwang, Yawon; Kashif, Muhammad; Jeong, Dosun; Kim, Gonhyung

    This study was conducted to evaluate the capacity of guiding bone regeneration of polyhydroxyethyl-polymethyl methacrylate (PHEMA-PMMA) membrane as a guided tissue regeneration membrane for bone defects. Two 8-mm diameter transosseous round defects were made at the parietal bone of 18 New Zealand White rabbits. Defects were covered with or without PHEMA-PMMA membrane. Radiological and histological evaluation revealed that the bone tissue over the defect was more regenerated with time in both groups. However, there was significantly more bone regeneration at 8 weeks in the experimental group than the control group (p<0.05). There was no sign of membrane degradation or tissue inflammation and no invasion of muscle and fibrous tissue into defects. PHEMA-PMMA is a potential material for guided tissue regeneration membrane as it induces no adverse tissue reaction and effectively supports selective bone regeneration.

  19. Development and characterisation of molecularly imprinted polymers based on methacrylic acid for selective recognition of drugs.

    PubMed

    Shi, Xizhi; Wu, Aibo; Qu, Guorun; Li, Rongxiu; Zhang, Dabing

    2007-09-01

    Specific molecularly imprinted polymers (MIPs) for the drug reserpine (RES) using methacrylic acid (MAA) as the functional monomer were developed and characterised for the first time in this study. Evaluation of the various polymers by binding assays indicated that the optimum ratio of functional monomer to template was 4:1. Furthermore, the imprinting effect of the MIPs was assessed by the chromatographic method, which demonstrated that the MIPs had better chromatographic behavior and selectivity than those of the corresponding NIPs. A combination of BET, NMR, UV spectroscopy, and MISPE analyses for investigation of the imprinting and recognition properties revealed that strong specific interactions between the functional monomer and RES in the prepolymerization solutions and the aqueous solutions were probably responsible for RES recognition. The preparation of RES MIPs and elucidation of imprinting and recognition mechanisms may serve as useful references for other drug MIPs.

  20. Crosslinked polymer gel electrolytes based on polyethylene glycol methacrylate and ionic liquid for lithium battery applications

    SciTech Connect

    Liao, Chen; Sun, Xiao-Guang; Dai, Sheng

    2013-01-01

    Gel polymer electrolytes were synthesized by copolymerization polyethylene glycol methyl ether methacrylate with polyethylene glycol dimethacrylate in the presence of a room temperature ionic liquid, methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPPY TFSI). The physical properties of gel polymer electrolytes were characterized by thermal analysis, impedance spectroscopy, and electrochemical tests. The ionic conductivities of the gel polymer electrolytes increased linearly with the amount of MPPY TFSI and were mainly attributed to the increased ion mobility as evidenced by the decreased glass transition temperatures. Li||LiFePO4 cells were assembled using the gel polymer electrolytes containing 80 wt% MPPY TFSI via an in situ polymerization method. A reversible cell capacity of 90 mAh g 1 was maintained under the current density of C/10 at room temperature, which was increased to 130 mAh g 1 by using a thinner membrane and cycling at 50 C.

  1. Non-viscoelastic Alloy by Reactive Blending of Nylon with Poly(ethylene-co-glycidyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Sato, Daisuke; Kadowaki, Yuji; Ishibashi, Junya; Kobayashi, Sadayuki; Inoue, Takashi

    Polyamide (PA) was blended with a reactive polyolefin, poly(ethylene-co-glycidyl methacrylate), using an extremely long (L/D=100, L: screw length, D: screw diameter) twin-screw extruder. The reactive blending yielded a unique morphology of the sub-μm polyolefin particles in which 20 nm PA micelles were occluded. It implies that the in situ-formed graft copolymer was pulled in the dispersed particles. The blend showed ultra-high toughness (non-break at Izod impact test) and non-viscoelastic tensile property: the higher deformation rate led to the lower modulus and the larger elongation at break. In the tensile stress-strain curve, the sharp yielding point characteristic to crystalline polymer was hardly seen and the necking stress was maintained almost constant without strain hardening. It suggests a potential application for the energy absorbing car parts, to be friendly for pedestrian and driver.

  2. The role and impact of rubber in poly(methyl methacrylate)/lithium triflate electrolyte

    NASA Astrophysics Data System (ADS)

    Latif, Famiza; Aziz, Madzlan; Katun, Nasir; Ali, Ab Malik Marwan; Yahya, Muhd Zuazhan

    In this research, new thin freestanding films of poly(methyl methacrylate) (PMMA)/50% epoxidised natural rubber (ENR 50) were doped with lithium triflate, LiCF 3SO 3 salt was prepared by a solvent casting method. The incorporation of ENR 50 is found to increase the conductivity of PMMA/LiCF 3SO 3 by two orders of magnitude at room temperature. The highest conductivity achieved was 5.09 × 10 -5 S cm -1 at room temperature when 60% of LiCF 3SO 3 salt was introduced into the PMMA blend containing 10% ENR 50. The formation of excessive hydrogen bonds and interchain crosslinking limit the performance of the blend at higher concentrations of ENR 50. The ionic conduction mechanisms in PMMA/ENR 50/LiCF 3SO 3 electrolytes obey the Arrhenius rule in which the ion transport in these materials is thermally assisted.

  3. Synthesis, characterization and fluorescence studies of novel bi-phenyl based acrylate and methacrylate

    NASA Astrophysics Data System (ADS)

    Baskar, R.; Subramanian, K.

    2011-09-01

    4-[(1 E)-3-(biphenyl-4-yl)buta-1,3-dien-1-yl]phenyl prop-2-enoate ( ACH) and 4-[(1 E)-3-(biphenyl-4-yl)buta-1,3-dien-1-yl]phenyl 2-methylprop-2-enoate ( MCH) was synthesized from biphenyl in three steps and their structures were confirmed by elemental analysis, IR, NMR ( 1H, 13C, DEPT135, 1H- 1H COSY, 1H- 13C HSQC and 1H- 13C HMBC) spectroscopic techniques. In this present study, various physicochemical characteristics we demonstrate solubility, color, absorbance and fluorescence property of novel biphenyl based acrylate and methacrylate measured in different solvents like benzene, dichloromethane, tetrahydrofuran, acetonitrile, dimethylsulfoxide and ethanol.

  4. Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations

    NASA Astrophysics Data System (ADS)

    Liu, Chaozong; Cui, Nai-Yi; Osbeck, Susan; Liang, He

    2012-10-01

    This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15 min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

  5. Tuning of cross-linking and mechanical properties of laser-deposited poly (methyl methacrylate) films

    NASA Astrophysics Data System (ADS)

    Süske, Erik; Scharf, Thorsten; Krebs, Hans-Ulrich; Panchenko, Elena; Junkers, Thomas; Egorov, Mark; Buback, Michael; Kijewski, Harald

    2005-03-01

    The chemical composition, amount of cross-linking and its influence on the mechanical properties of poly(methyl methacrylate) (PMMA) thin films produced by pulsed laser deposition (PLD) at a wavelength of 248nm under ultrahigh vacuum were investigated by infrared spectroscopy, scanning electron microscopy, size-exclusion chromatography, thermogravimetric analysis, and nanoindentation experiments. The films consist of two components, one fraction with a molecular weight well below that of the target material and a second fraction, which is cross-linked. Compared to bulk material, the Young's modulus of the film is increased. The amount of cross-linking in the film can be tuned by the applied laser fluence leading to changes of the mechanical properties.

  6. Radiation grafting of oligo(ethylene glycol) ethyl ether methacrylate on polypropylene

    NASA Astrophysics Data System (ADS)

    Komasa, Justyna; Miłek, Andrzej; Ulański, Piotr; Rosiak, Janusz M.

    2014-01-01

    Oligo(ethylene glycol) ethyl ether methacrylate (OEGMA) can be grafted onto polypropylene (PP) films by post-irradiation grafting, forming a thermosensitive polymer layer, as indicated by FT-IR and contact angle measurements. In the first step, PP foils are irradiated by electron beam (5.5 kGy/min, up to 300 kGy) in the presence of air. Subsequently, the irradiated foils react with the monomer in oxygen-free solutions in isopropanol (up to 2 M of monomer) at 70 °C. Degree of grafting of OEGMA can be controlled by proper selection of absorbed dose, monomer concentration and reaction time. This work is a part of a broader project on thermosensitive materials facilitating cell growth and detachment for optimizing cell layer engineering techniques in the treatment of burn wounds.

  7. Hydrophobic modification of cellulose isolated from Agave angustifolia fibre by graft copolymerisation using methyl methacrylate.

    PubMed

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan; Mohamed, Faizal

    2015-07-10

    Graft copolymerisation of methyl methacrylate (MMA) onto Agave angustifolia was conducted with ceric ammonium nitrate (CAN) as the redox initiator. The maximum grafting efficiency was observed at CAN and MMA concentrations of 0.91 × 10(-3) and 5.63 × 10(-2)M, respectively, at 45°C for 3h reaction time. Four characteristic peaks at 2995, 1738, 1440, and 845 cm(-1), attributed to PMMA, were found in the IR spectrum of grafted cellulose. The crystallinity index dropped from 0.74 to 0.46, while the thermal stability improved upon grafting. The water contact angle increased with grafting yield, indicating increased hydrophobicity of cellulose. SEM images showed the grafted cellulose to be enlarged and rougher. The changes in the physical nature of PMMA-grafted cellulose can be attributed to the PMMA grafting in the amorphous regions of cellulose, causing it to expand at the expense of the crystalline component. PMID:25857961

  8. Dissolution And Swelling Studies Of Poly(Methyl Methacrylate) Resist Films

    NASA Astrophysics Data System (ADS)

    Papanu, J. S.; Manjkow, J.; Hess, D. W.; Soong, D. S.; Bell, A. T.

    1987-08-01

    The swelling and dissolution of thin film poly(methyl methacrylate), PMMA, in methyl isobutyl ketone (MIBK), and in solvent/nonsolvent mixtures of MIBK/methanol and methyl ethyl ketone/isopropanol have been investigated. Films were monitored using in situ ellipsometry. Parametric studies of the effects of molecular weight, molecular weight distribution, softbaking quench rate, solvent size, and temperature were performed with MIBK. These parameters were shown to have a significant effect on dissolution. The effects of solvent composition and temperature on swelling and dissolution were investigated with the binary solvents. Ternary diagrams based on Flory-Huggins interaction parameters were used to interpret the thermodynamics of swelling and dissolution. A narrow transition region (NTR) where the developer changed from a swelling to dissolving agent with a small change in composition or temperature was observed.

  9. Direct measurements of the mechanical strength of carbon nanotube-poly(methyl methacrylate) interfaces.

    PubMed

    Chen, Xiaoming; Zheng, Meng; Park, Cheol; Ke, Changhong

    2013-10-11

    Understanding the interfacial stress transfer between carbon nanotubes (CNTs) and polymer matrices is of great importance to the development of CNT-reinforced polymer nanocomposites. In this paper, an experimental study is presented of the interfacial strength between individual double-walled CNTs and poly(methyl methacrylate) (PMMA) using an in situ nanomechanical single-tube pull-out testing scheme inside a high-resolution electron microscope. By pulling out individual tubes with different embedded lengths, this work reveals the shear lag effect on the nanotube-polymer interface and demonstrates that the effective interfacial load transfer occurs only within a certain embedded length. These results show that the CNT-PMMA interface possesses an interfacial fracture energy within 0.054-0.80 J/m(2) and a maximum interfacial strength within 85-372 MPa. This work is useful to better understand the local stress transfer on nanotube-polymer interfaces.

  10. Raman spectra of bilayer graphene covered with Poly(methyl methacrylate) thin film

    SciTech Connect

    Xia Minggang; Su Zhidan; Zhang Shengli

    2012-09-15

    The Raman spectra of bilayer graphene covered with poly(methyl methacrylate) (PMMA) were investigated. Both the G and 2D peaks of PMMA-coated graphene were stiff and broad compared with those of uncovered graphene. This could be attributed to the residual strain induced by high-temperature baking during fabrication of the nanodevice. Furthermore, the two 2D peaks stiffened and broadened with increasing laser power, which is just the reverse to uncovered graphene. The stiffness is likely caused by graphene compression induced by the circular bubble of the thin PMMA film generated by laser irradiation. Our findings may contribute to the application of PMMA in the strain engineering of graphene nanodevices.

  11. Surface-initiated atom transfer radical polymerization of methyl methacrylate from magnetite nanoparticles at ambient temperature.

    PubMed

    Raghuraman, G K; Dhamodharan, R

    2006-07-01

    The synthesis of methyl methacrylate (MMA) brush from the surface of magnetite nanoparticles (core-shell structure), from initiator moieties anchored covalently to the nanoparticles, via room temperature atom transfer radical polymerization (ATRP) is described. The surface-initiated polymerization was carried out from a surface-confined initiator containing a 2-bromoisobutyrate moiety with Cu(I)Br/PMDETA catalytic system. The initiator moiety was covalently anchored to the nanoparticles via a two step modification reaction scheme. Controlled polymerization was observed if ethyl-2-bromoisobutyrate (2-EiBrB) was added as a free/sacrificial initiator. A linear increase of molecular weight and a narrow molecular weight distribution of the PMMA formed in solution, provide evidence for a controlled surface-initiated polymerization, leading to surface-attached polymer brushes under mild conditions. The grafted PMMA provides good stability and dispersibility for the nanoparticles in organic solvents.

  12. Evaluation of Bone Regeneration on Polyhydroxyethyl-polymethyl Methacrylate Membrane in a Rabbit Calvarial Defect Model.

    PubMed

    Kim, Somin; Hwang, Yawon; Kashif, Muhammad; Jeong, Dosun; Kim, Gonhyung

    This study was conducted to evaluate the capacity of guiding bone regeneration of polyhydroxyethyl-polymethyl methacrylate (PHEMA-PMMA) membrane as a guided tissue regeneration membrane for bone defects. Two 8-mm diameter transosseous round defects were made at the parietal bone of 18 New Zealand White rabbits. Defects were covered with or without PHEMA-PMMA membrane. Radiological and histological evaluation revealed that the bone tissue over the defect was more regenerated with time in both groups. However, there was significantly more bone regeneration at 8 weeks in the experimental group than the control group (p<0.05). There was no sign of membrane degradation or tissue inflammation and no invasion of muscle and fibrous tissue into defects. PHEMA-PMMA is a potential material for guided tissue regeneration membrane as it induces no adverse tissue reaction and effectively supports selective bone regeneration. PMID:27566076

  13. A new rapid silver impregnation for neuronal bodies on methacrylate sections.

    PubMed

    Tolivia, D; Tolivia, J

    1991-02-01

    A simple and rapid method for the impregnation of neuronal bodies applicable to methacrylate embedded sections is described in the present paper. Sections of 10-12 microns in thickness were attached to slides, placed in mordant for 1 min, rinsed in distilled water and impregnated in ammoniacal silver solution for 1 min. They were then rinsed in absolute ethanol for 30 s and developed in 50% formalin. Sections were toned in 0.25% gold chloride, reduced in 10% oxalic acid and fixed in 5% sodium thiosulfate. After washing, the sections were dehydrated through 90% and absolute ethanol, cleared in eucalyptol, and mounted in the usual way. When this method is used most of the neuronal somata and proximal dendritic trees are impregnated. Frequently some glial cell are also weakly impregnated but their density does not obscure the neurons.

  14. Preparation And Lithographic Properties Of Poly(Trimethylsilylmethyl Methacrylate-Co-Chloromethyl Styrene)

    NASA Astrophysics Data System (ADS)

    Novembre, Anthony E.; Reichmanis, Elsa; Davis, Myrtle

    1986-07-01

    The random copolymer comprised of trimethylsilylmethyl methacrylate (SI) and chloromethyl styrene (CMS) is shown to function as a negative acting e-beam and deep UV resist. The resist is prepared using free radical solution polymerization techniques. Reactivity ratios were calculated using the least squares treatment of Fineman-Ross, and were determined to be 0.49 and 0.54 for SI and CMS, respectively. This material exhibits etching resistance in an 02 reactive ion etching discharge, and is applicable to bileveli pthographic processes. The resist system exhibits an e-beam and deep UV sensitivity (pg. ) equal to 1.95 11C/cm2 and 18mJ/cm2, respectively. The ratio of etching rates of the planarizing layer HPR-206 to this material is 12 to 1 in 02. Preliminary results indicate this system to have submicron resolution capability.

  15. Facile One-step Micropatterning Using Photodegradable Methacrylated Gelatin Hydrogels for Improved Cardiomyocyte Organization and Alignment

    PubMed Central

    Tsang, Kelly M.C.; Annabi, Nasim; Ercole, Francesca; Zhou, Kun; Karst, Daniel; Li, Fanyi; Haynes, John M.; Evans, Richard A.; Thissen, Helmut

    2015-01-01

    Hydrogels are often employed as temporary platforms for cell proliferation and tissue organization in vitro. Researchers have incorporated photodegradable moieties into synthetic polymeric hydrogels as a means of achieving spatiotemporal control over material properties. In this study protein-based photodegradable hydrogels composed of methacrylated gelatin (GelMA) and a crosslinker containing o-nitrobenzyl ester groups have been developed. The hydrogels are able to degrade rapidly and specifically in response to UV light and can be photopatterned to a variety of shapes and dimensions in a one-step process. Micropatterned photodegradable hydrogels are shown to improve cell distribution, alignment and beating regularity of cultured neonatal rat cardiomyocytes. Overall this work introduces a new class of photodegradable hydrogel based on natural and biofunctional polymers as cell culture substrates for improving cellular organization and function. PMID:26327819

  16. Synthesis, characterization, and antimicrobial activity of poly(acrylonitrile-co-methyl methacrylate) with silver nanoparticles.

    PubMed

    El-Aassar, M R; Hafez, Elsayed E; Fouda, Moustafa M G; Al-Deyab, Salem S

    2013-10-01

    Nanotechnology is expected to open some new aspects to fight and prevent diseases using atomic-scale tailoring of materials. The main aim of this study is to biosynthesize silver nanoparticles (AgNPs) using Trichoderma viride (HQ438699); the metabolite of this fungus will help either in reduction of the silver nitrate-adding active materials which will be loaded on the surface of the produced AgNPs. Poly(acrylonitrile-co-methyl methacrylate) copolymer (poly (AN-co-MMA)) was grafted with the prepared AgNPs. The poly(AN-co-MMA)/AgNPs were examined against ten different pathogenic bacterial strains, and the result was compared with another four different generic antibiotics. The produced poly(AN-co-MMA)/AgNPs showed high antibacterial activity compared with the four standard antibiotics. Moreover, the grafting of these AgNPs into the copolymer has potential application in the biomedical field. PMID:23873643

  17. Preparation of medical magnetic nanobeads with ferrite particles encapsulated in a polyglycidyl methacrylate (GMA) for bioscreening

    SciTech Connect

    Nishibiraki, H.; Kuroda, C.S.; Maeda, M.; Matsushita, N.; Abe, M.; Handa, H.

    2005-05-15

    Ferrite nanoparticles (an intermediate between Fe{sub 3}O{sub 4} and {gamma}-Fe{sub 2}O{sub 3}), {approx}7 nm in diameter, were embedded in beads of a mixed polymer of styrene (St) and glycidyl methacrylate (GMA) by emulsifier-free emulsion polymerization method. The beads were coated with GMA by a seeded polymerization method in order to suppress nonspecific protein binding on the surfaces; GMA exhibits very low nonspecific protein binding, which is required for carriers used for bioscreening. The beads have diameters of 180{+-}50 nm and saturation magnetizations of 28 emu/g, exceeding commercially available polymer-coated beads of micron size having a weaker saturation magnetization ({approx}12 emu/g)

  18. Interaction between physical aging, deformation, and segmental mobility in poly(methyl methacrylate) glasses

    NASA Astrophysics Data System (ADS)

    Lee, Hau-Nan; Ediger, M. D.

    2010-07-01

    Optical photobleaching experiments were used to investigate the interaction between physical aging, segmental mobility, and mechanical properties in polymer glasses. Mechanical creep experiments were performed on lightly cross-linked poly(methyl methacrylate) glasses with systematically varying aging histories. By directly measuring the molecular mobility of polymer glasses under deformation, we observe that stresses in the preflow regime and flow regime have qualitatively different influences on the aging process. In the preflow regime, the effects of aging and stress on mobility act as two independent processes; stress causes an increase in segmental mobility but does not erase the influence of previous aging. In contrast, as a sample enters the flow regime, plastic deformation takes the glass into a high mobility state that is independent of any predeformation aging history.

  19. Cellulose functionalization via high-energy irradiation-initiated grafting of glycidyl methacrylate and cyclodextrin immobilization

    NASA Astrophysics Data System (ADS)

    Desmet, Gilles; Takács, Erzsébet; Wojnárovits, László; Borsa, Judit

    2011-12-01

    Cotton-cellulose was functionalized using gamma-irradiation-induced grafting of glycidyl methacrylate (GMA) to obtain a hydrophobic cellulose derivative with epoxy groups suitable for further chemical modification. Two grafting techniques were applied. In pre-irradiation grafting (PIG) cellulose was irradiated in air and then immersed in a GMA monomer solution, whereas in simultaneous grafting (SG) cellulose was irradiated in an inert atmosphere in the presence of the monomer. PIG led to a more homogeneous fiber surface, while SG resulted in higher grafting yield but showed clear indications of some GMA-homopolymerization. Effects of the reaction parameters (grafting method, absorbed dose, monomer concentration, solvent composition) were evaluated by SEM, gravimetry (grafting yield) and FTIR spectroscopy. Water uptake of the cellulose decreased while adsorption of a pesticide molecule increased upon grafting. The adsorption was further enhanced by β-cyclodextrin immobilization during SG. This method can be applied to produce adsorbents from cellulose based agricultural wastes.

  20. Thermoelastic temperature changes in poly(methyl methacrylate) at high hydrostatic pressure: Experimental

    NASA Astrophysics Data System (ADS)

    Rodriquez, E. L.; Filisko, F. E.

    1982-10-01

    Temperature changes as a result of large rapid hydrostatic pressure changes were measured for poly(methyl methacrylate) at various temperatures from ambient to 95 °C and for various pressure increments from 14 to 207 MN/m2. We observe complete reversibility of the measurements over the pressure range studied. The value of the incremental ratio ΔT/ΔP was a function of both temperature and pressure, ranging from 0.04 to 0.09 K/MNm-2 from 298 to 368 K at low pressures, and 0.03-0.05 at 200 MN/m2 over the same temperature range. The largest variation of ΔT/ΔP with pressure was at low pressures, the ratio becoming nearly constant above about 200 MN/M2.

  1. Novel (meth)acrylate monomers for ultrarapid polymerization and enhanced polymer properties

    SciTech Connect

    Beckel, E. R.; Berchtold, K. A.; Nie, J.; Lu, H.; Stansbury, J. W.; Bowman, C. N.

    2002-01-01

    Ultraviolet light is known to be one of the most efficient methods to initiatc polymeric reactions in the presence of a photonitiator. Photopolymerizations are advantageous because the chemistry of the materials can be tailored to design liquid monomers for ultrarapid polymerization into a solid polymer material. One way to achieve rapid photopolymerizations is to utilize multifunctional (meth)acrylate monomers. which form highly crosslinked polymers; however, these monomers typically do not achieve complete functional group conversion. Recently, Decker et al. developed novel monovinyl acrylate monomers that display polyriicrization kinetics that rival those of multifunctional acrylate monomers. These novel acrylate monomers incorporate secondary functionalities and end groups such as carbonates, carbamates, cyclic carbonates and oxazolidone which promote the increased polymerization kinetics of these monomers. In addition to thc polynierization kinetics, these novel monovinyl monomers form crosslinked polymers, which are characterized by having high strength and high flexibility. Unfortunately, the exact mechanism or mechanisms responsible for the polymerization kinetics and crosslinking are not well understood.

  2. Near-field mapping of plasmonic antennas by multiphoton absorption in poly(methyl methacrylate).

    PubMed

    Volpe, Giorgio; Noack, Monika; Aćimović, Srdjan S; Reinhardt, Carsten; Quidant, Romain

    2012-09-12

    Mapping the optical near-field response around nanoantennas is a challenging yet indispensable task to engineer light-matter interaction at the nanometer scale. Recently, photosensitive molecular probes, which undergo morphological or chemical changes induced by the local optical response of the nanostructures, have been proposed as a handy alternative to more cumbersome optical and electron-based techniques. Here, we report four-photon absorption in poly(methyl methacrylate) (PMMA) as a very promising tool for nanoimaging the optical near-field around nanostructures over a broad range of near-infrared optical wavelengths. The high performance of our approach is demonstrated on single-rod antennas and coupled gap antennas by comparing experimental maps with 3D numerical simulations of the electric near-field intensity.

  3. Poly(methacrylic acid)-mediated morphosynthesis of PbWO4 micro-crystals

    NASA Astrophysics Data System (ADS)

    Yu, J. G.; Zhao, X. F.; Liu, S. W.; Li, M.; Mann, S.; Ng, D. H. L.

    2007-04-01

    PbWO4 crystals with various morphologies were fabricated via a facile poly(methacrylic acid)-mediated hydrothermal route. Novel microsized PbWO4 single crystals with a needle-like shape as well as other morphologies, such as a fishbone, dendrite, sphere, spindle, ellipsoid, rod, and dumbbell with two dandelion-like heads, could be produced. The presence of PMAA, [Pb2+]/[WO4 2-] molar ratio (R), and aging temperature played key roles in the formation of the PbWO4 needle-like structures. Between temperatures of 60 to 150 °C, the length and photoluminescence intensities of the PbWO4 micro needles significantly increased with aging temperature, while the diameter did not change remarkably. Time-dependent experiments revealed that the formation of PbWO4 microneedles involved an unusual growth process, involving nucleation, oriented assembly and controlled mesoscale restructuring of nanoparticle building blocks.

  4. Poly(N-vinylcaprolactam-co-methacrylic acid) hydrogel microparticles for oral insulin delivery.

    PubMed

    Mundargi, Raghavendra C; Rangaswamy, Vidhya; Aminabhavi, Tejraj M

    2011-01-01

    pH-sensitive copolymeric hydrogels prepared from N-vinylcaprolactam and methacrylic acid monomers by free radical polymerization offered 52% encapsulation efficiency and evaluated for oral delivery of human insulin. The in vitro experiments performed on insulin-loaded microparticles in pH 1.2 media (stomach condition) demonstrated no release of insulin in the first 2 h, but almost 100% insulin was released in pH 7.4 media (intestinal condition) in 6 h. The carrier was characterized by Fourier transform infrared, differential scanning calorimeter, thermogravimetry and nuclear magnetic resonance techniques to confirm the formation of copolymer, while scanning electron microscopy was used to assess the morphology of hydrogel microparticles. The in vivo experiments on alloxan-induced diabetic rats showed the biological inhibition up to 50% and glucose tolerance tests exhibited 44% inhibition. The formulations of this study are the promising carriers for oral delivery of insulin.

  5. Fabrication of Poly (methyl methacrylate) and Poly(vinyl alcohol) Thin Film Capacitors on Flexible Substrates

    NASA Astrophysics Data System (ADS)

    Salim, Bindu; Meenaa Pria KNJ, Jaisree; Alagappan, M.; Kandaswamy, A.

    2015-11-01

    Flexible electronics is becoming more popular with introduction of more and more organic conducting materials and processes for making thin films. The use of polymers as gate dielectric has over ruled the usage of conventional inorganic oxides in Organic Thin Film Transistors (OTFTs) on account of its solution process ability and ease of making highly insulating thin film. In this work Capacitance is fabricated with polymeric dielectrics namely poly (methyl methacrylate) - PMMA and poly (vinyl alcohol) - PVA. The electrodes used for these capacitors are Indium Tin Oxide (ITO) and Aluminium. Capacitance value of 9.5nF/cm2 and 33.12nF/cm2 is achieved for thickness of 510 nm of PMMA and 80 nm of PVA respectively. This study on capacitance can be used for assessing the suitability of these polymers as gate insulators in OTFTs.

  6. Mechanical properties of methacrylate-based model dentin adhesives: effect of loading rate and moisture exposure.

    PubMed

    Singh, Viraj; Misra, Anil; Parthasarathy, Ranganathan; Ye, Qiang; Park, Jonggu; Spencer, Paulette

    2013-11-01

    The aim of this study is to investigate the mechanical behavior of model methacrylate-based dentin adhesives under conditions that simulate the wet oral environment. A series of monotonic and creep experiments were performed on rectangular beam samples of dentin adhesive in three-point bending configuration under different moisture conditions. The monotonic test results show a significant effect of loading rate on the failure strength and the linear limit (yield point) of the stress-strain response. In addition, these tests show that the failure strength is low, and the failure occurs at a smaller deformation when the test is performed under continuously changing moisture conditions. The creep test results show that under constant moisture conditions, the model dentin adhesives can have a viscoelastic response under certain low loading levels. However, when the moisture conditions vary under the same low loading levels, the dentin adhesives have an anomalous creep response accompanied by large secondary creep and high strain accumulation. PMID:23744598

  7. Miniemulsion fabricated Fe3O4/poly(methyl methacrylate) composite particles and their magnetorheological characteristics

    NASA Astrophysics Data System (ADS)

    Park, B. O.; Song, K. H.; Park, B. J.; Choi, H. J.

    2010-05-01

    In order to improve drawbacks such as sedimentation of magnetic particles and abrasion of the magnetorheological (MR) fluid, we have fabricated Fe3O4/poly(methyl methacrylate) (PMMA) composite particles via a double miniemulsion method and studied their MR properties. Morphology and chemical composition of the synthesized Fe3O4/PMMA composite particles were investigated by transmission electron microscopy and Fourier transform infrared, respectively. The density of the Fe3O4/PMMA composite particles was measured to be lower than that of the as-synthesized Fe3O4 particles, indicative of an improvement of the composite particles to stay dispersed. Rheological characteristics of the Fe3O4/PMMA based MR fluid dispersed in a nonmagnetic carrier fluid were measured by both static and dynamic tests using a rotational rheometer under an external magnetic field. Shear stress, yield stress, and storage modulus from the rheological measurements were obtained to be increased with applied magnetic field strengths.

  8. Hydrophobic modification of cellulose isolated from Agave angustifolia fibre by graft copolymerisation using methyl methacrylate.

    PubMed

    Rosli, Noor Afizah; Ahmad, Ishak; Abdullah, Ibrahim; Anuar, Farah Hannan; Mohamed, Faizal

    2015-07-10

    Graft copolymerisation of methyl methacrylate (MMA) onto Agave angustifolia was conducted with ceric ammonium nitrate (CAN) as the redox initiator. The maximum grafting efficiency was observed at CAN and MMA concentrations of 0.91 × 10(-3) and 5.63 × 10(-2)M, respectively, at 45°C for 3h reaction time. Four characteristic peaks at 2995, 1738, 1440, and 845 cm(-1), attributed to PMMA, were found in the IR spectrum of grafted cellulose. The crystallinity index dropped from 0.74 to 0.46, while the thermal stability improved upon grafting. The water contact angle increased with grafting yield, indicating increased hydrophobicity of cellulose. SEM images showed the grafted cellulose to be enlarged and rougher. The changes in the physical nature of PMMA-grafted cellulose can be attributed to the PMMA grafting in the amorphous regions of cellulose, causing it to expand at the expense of the crystalline component.

  9. Enhancement of impact strength of poly (methyl methacrylate) with surface fine-tuned nano-silica

    NASA Astrophysics Data System (ADS)

    Wen, Bin; Dong, Yixiao; Wu, Lili; Long, Chao; Zhang, Chaocan

    2015-07-01

    Highly dispersible nanoparticles in organic solvent always receive wide interests due to their compatibility with polymer materials. This paper reported a kind of isopropanol alcohol silica dispersion which obtained using a method of azeotropic distillation. The isopropanol alcohol dispersed silica (IPADS) were treated with coupling agents to fine-tune their surface properties. Polymethyl methacrylate (PMMA) was then used as a research object to test the compatibility between IPADS and polymer. UV-vis spectra indicate that IPADS would reach its high compatibility with PMMA if coupling with trimethoxypropylsilane (PTMS). Followed experiments on PMMA proved that the high compatibility can prominently enhance the impact strength about 30%. The results may provide reference both for nano-silica modification and better understanding of nano-enhanced materials.

  10. Dye-attached magnetic poly(hydroxyethyl methacrylate) nanospheres for albumin depletion from human plasma.

    PubMed

    Gökay, Öznur; Karakoç, Veyis; Andaç, Müge; Türkmen, Deniz; Denizli, Adil

    2015-02-01

    The selective binding of albumin on dye-affinity nanospheres was combined with magnetic properties as an alternative approach for albumin depletion from human plasma. Magnetic poly(hydroxyethyl methacrylate) (mPHEMA) nanospheres were synthesized using mini-emulsion polymerization method in the presence of magnetite powder. The specific surface area of the mPHEMA nanospheres was found to be 1302 m(2)/g. Subsequent to Cibacron Blue F3GA (CB) immobilization onto mPHEMA nanospheres, a serial characterization processing was implemented. The quantity of immobilized CB was calculated as 800 μmol/g. Ultimately, albumin adsorption performance of the CB-attached mPHEMA nanospheres from both aqueous dissolving medium and human plasma were explored.

  11. Phosphate sensor based on immobilized aluminium-morin in poly (glycidyl methacrylate) microspheres

    NASA Astrophysics Data System (ADS)

    Ahmad, Amalina; Hanifah, Sharina Abu; Hasbullah, Siti Aishah; Suhud, Khairi; Zaini, Norhadisah Mohd; Heng, Lee Yook

    2014-09-01

    This paper reports the development of dihydrogen phosphate ion (H2PO4-) sensor in free solution and immobilized aluminium-morin (Al-Mo) complex on poly(glycidyl methacrylate) (pGMA) microspheres. The immobilization was carried out by suspension photopolymerization technique. Based on Al-Mo solution work, phosphate can be detected from 0.1 - 15.0 ppm of dihydrogen phosphate at pH 5. Phosphate detection only takes about 5 minutes. Morphology analyses showed that the immobilization of Aluminium-Morin complex maintained the size of the microspheres and proved that entrapment involves in the formation of the microspheres. This result is further explained by Attenuated Total Reflectance (ATR) spectrum which does not show any formation of new bands. The microspheres were then used for further applications.

  12. Electron capture of dopants in two-photonic ionization in a poly(methyl methacrylate) solid

    SciTech Connect

    Tsuchida, Akira; Sakai, Wataru; Nakano, Mitsuru; Yamamoto, Masahide

    1992-10-29

    Behavior of the electron produced by two-photonic excitation of an aromatic donor in a poly(methyl methacrylate) solid was studied by the addition of the electron scavengers to the system. According to the Perrin type analysis for the two-photonically ejected electron, the capture radii (R{sub c}) of the scavengers examined were estimated to be from 8 to 40 {Angstrom}. For the two-photonically ejected electrons, R{sub c} is a capture radius for thermalized electrons. In this case the parent electron donor is not necessarily within this radius. On the other hand, for the fluorescence quenching, the distance between the donor and acceptor is within the static quenching radius (R{sub q}) of the donor. 13 refs., 4 figs., 2 tabs.

  13. Thermal-induced conversion of maleic and fumaric acid anion radicals in poly(methyl methacrylate)

    SciTech Connect

    Torikai, A.; Fukumoto, M.

    1980-04-01

    Thermal-induced conversion of maleic and fumaric acid anion radicals produced by ..gamma.. irradiation at 77/sup 0/K in poly(methyl methacrylate) (PMMA) was studied by electron spin resonance (ESR) and optical absorption spectroscopic measurements. The ESR spectra of these acid anion radicals change into two-line spectra with a line separation of ca. 10 G by thermal annealing. This spectrum is assigned to a protonated radical of each acid anion radical. Anion radicals of the solutes are relatively stable below the ..gamma.. transition point of PMMA and the conversion reaction takes place near this point. This means that the molecular motion of matrix molecule affects the radical conversion reaction.

  14. Facile Soap-Free Miniemulsion Polymerization of Methyl Methacrylate via Reverse Atom Transfer Radical Polymerization.

    PubMed

    Zhu, Gaohua; Zhang, Lifen; Pan, Xiangqiang; Zhang, Wei; Cheng, Zhenping; Zhu, Xiulin

    2012-12-21

    A facile soap-free miniemulsion polymerization of methyl methacrylate (MMA) was successfully carried out via a reverse ATRP technique, using a water-soluble potassium persulfate (KPS) or 2,2'-azobis(2-methylpropionamidine) dihydrochloride (V-50) both as the initiator and the stabilizer, and using an oil-soluble N,N-n-butyldithiocarbamate copper (Cu(S2CN(C4H9)2)2) as the catalyst without adding any additional ligand. Polymerization results demonstrated the "living"/controlled characteristics of ATRP and the resultant latexes showed good colloidal stability with average particle size around 300-700 nm in diameter. The monomer droplet nucleation mechanism was proposed. NMR spectroscopy and chain-extension experiments under UV light irradiation confirmed the attachment and livingness of UV light sensitive -S-C(=S)-N(C4H9)2 group in the chain end. PMID:23019131

  15. Methyl methacrylate as a healing agent for self-healing cementitious materials

    NASA Astrophysics Data System (ADS)

    Van Tittelboom, K.; Adesanya, K.; Dubruel, P.; Van Puyvelde, P.; De Belie, N.

    2011-12-01

    Different types of healing agents have already been tested on their efficiency for use in self-healing cementitious materials. Generally, commercial healing agents are used while their properties are adjusted for manual crack repair and not for autonomous crack healing. Consequently, the amount of regain in properties due to self-healing of cracks is limited. In this research, a methyl methacrylate (MMA)-based healing agent was developed specifically for use in self-healing cementitious materials. Various parameters were optimized including the viscosity, curing time, strength, etc. After the desired properties were obtained, the healing agent was encapsulated and screened for its self-healing efficiency. The decrease in water permeability due to autonomous crack healing using MMA as a healing agent was similar to the results obtained for manually healed cracks. First results seem promising: however, further research needs to be undertaken in order to obtain an optimal healing agent ready for use in practice.

  16. Multidisciplinary approach for reconstruction of cranial defect with polymethyl methacrylate resin reinforced with titanium mesh.

    PubMed

    Sane, Vikrant Dilip; Kadam, Pankaj; Jadhav, Aniket; Saddiwal, Rashmi; Merchant, Yash

    2016-01-01

    Cranial defects occur most commonly as a sequelae to trauma, the incidence being as high as 70%. The successful management of a case of trauma in an emergency situation requires quick evacuation of the hematoma, repair of the dura, and the scalp but not necessarily the integrity of the calvarial segment as an immediate measure. So the reconstruction of the calvarial defect in these cases is mostly carried out as a secondary procedure. Various materials are used for reconstruction of cranial defects, polymethyl methacrylate (PMMA) resin being one of them. In this article, we report a case which was successfully treated by PMMA resin in combination with a titanium mesh for reconstruction of the cranial defect as a secondary procedure. PMID:27621551

  17. Thermosensitive poly(N-isopropylacrylamide-co-glycidyl methacrylate) microgels for controlled drug release.

    PubMed

    Li, Penghui; Xu, Ruizhen; Wang, Wenhao; Li, Xiaolong; Xu, Zushun; Yeung, Kelvin W K; Chu, Paul K

    2013-01-01

    A new type of thermosensitive microgels with epoxy functional groups is designed and synthesized for drug delivery. The thermosensitive poly(N-isopropylacrylamide-co-glycidyl methacrylate) (designated as P(NIPAM-co-GMA)) microgels are prepared by an emulsifier-free emulsion polymerization method and the chemical composition of the copolymer is determined by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance ((1)H NMR). The lower critical solution temperature (LCST) of the microgels is 32°C based on the transmittance changes at 500 nm monitored by UV/visible spectrophotometry. The hydrodynamic diameter and morphology of the microgel particles are examined by dynamic light scattering (DLS) and scanning electron microscopy (SEM), respectively. The drug release properties determined using 5-FU as the drug model in vitro reveal temperature dependence and low cytotoxicity. The thermosensitive microgels have large potential as targeted anti-cancer drug carriers. PMID:23010027

  18. Bonding efficacy and side effects of the high purity glyceryl mono-methacrylate.

    PubMed

    Takahashi, Y; Itoh, K; Manabe, A; Tani, C; Hisamitsu, H

    2004-12-01

    The purpose of this study was to examine the efficacy of experimentally developed high purity glyceryl mono-methacrylate (GM) as a dentine primer and to evaluate the possibility of allergic reaction. The efficacy of experimental dentine primers was evaluated by measuring the polymerization contraction gap width and the tensile bond strength. Allergic reaction was evaluated by the guinea-pig maximization test. The skin reaction was evaluated according to the criteria of the International Contact Dermatitis Research Group. Contraction gap formation was completely prevented and the tensile bond strength was not significantly affected by priming with GM on high-purity GM. The allergic response decreased when high-purity GM was employed as the challenger. It was concluded that the clinical use of the high-purity GM is beneficial as the delayed allergic reaction could be avoided with no detrimental effect on the dentine bonding. PMID:15544652

  19. Glycol methacrylate embedding for light microscopy. I. enzyme histochemistry on semithin sections of undecalcified marrow cores.

    PubMed

    Islam, A; Henderson, E S

    1987-10-01

    A simple, routine procedure for water miscible glycol methacrylate (GMA) embedding of undecalcified bone marrow cores, which preserves the activity of enzymes useful in diagnosing various haematopoietic disorders, is described. The GMA used in this study has a low acid content that eliminates background staining, and the modified May-Grünwald-Giemsa stain provides good definition and excellent colour differentiation of various haematopoietic cells in the bone marrow, thereby providing optimal conditions for the study of the morphology and enzyme activity of bone marrow cells in the same preparation. The method is simple, reproducible, requires no expensive equipment, and is suitable for routine processing of small bone marrow cores in any histopathology or haematology laboratory.

  20. New Poly(amino acid methacrylate) Brush Supports the Formation of Well-Defined Lipid Membranes

    PubMed Central

    2015-01-01

    A novel poly(amino acid methacrylate) brush comprising zwitterionic cysteine groups (PCysMA) was utilized as a support for lipid bilayers. The polymer brush provides a 12-nm-thick cushion between the underlying hard support and the aqueous phase. At neutral pH, the zeta potential of the PCysMA brush was ∼−10 mV. Cationic vesicles containing >25% DOTAP were found to form a homogeneous lipid bilayer, as determined by a combination of surface analytical techniques. The lipid mobility as measured by FRAP (fluorescence recovery after photobleaching) gave diffusion coefficients of ∼1.5 μm2 s–1, which are comparable to those observed for lipid bilayers on glass substrates. PMID:25746444

  1. Glycol Methacrylate Embedding for the Histochemical Study of the Gastrointestinal Tract of Dogs Naturally Infected with Leishmania Infantum

    PubMed Central

    Pinto, A.J.W.; de Amorim, I.F.G.; Pinheiro, L.J.; Madeira, I.M.V.M.; Souza, C.C.; Chiarini-Garcia, H.; Caliari, M.V.

    2015-01-01

    In canine visceral leishmaniasis a diffuse chronic inflammatory exudate and an intense parasite load throughout the gastrointestinal tract (GIT) has been previously reported. However, these studies did not allow a properly description of canine cellular morphology details. The aim of our study was to better characterize these cells in carrying out a qualitative and quantitative histological study in the gastrointestinal tract of dogs naturally infected with Leishmania infantum by examining gut tissues embedded in glycol methacrylate. Twelve infected adult dogs were classified in asymptomatic and symptomatic. Five uninfected dogs were used as controls. After necropsy, three samples of each gut segment, including oesophagus, stomach, duodenum, jejunum, ileum, cecum, colon, and rectum were collected and fixed in Carnoy’s solution for glycol methacrylate protocols. Sections were stained with hematoxylin-eosin, toluidine blue borate, and periodic acid-Schiff stain. Leishmania amastigotes were detected by immunohistochemistry employed in both glycol methacrylate and paraffin embedded tissues. The quantitative histological analysis showed higher numbers of plasma cells, lymphocytes and macrophages in lamina propria of all segments of GIT of infected dogs compared with controls. The parasite load was more intense and cecum and colon, independently of the clinical status of these dogs. Importantly, glycol methacrylate embedded tissue stained with toluidine blue borate clearly revealed mast cell morphology, even after mast cell degranulation. Infected dogs showed lower numbers of mast cells in all gut segments than controls. Despite the glycol methacrylate (GMA) protocol requires more attention and care than the conventional paraffin processing, this embedding procedure proved to be especially suitable for the present histological study, where it allowed to preserve and observe cell morphology in fine detail. PMID:26708180

  2. Supramolecular Cross-Links in Poly(alkyl methacrylate) Copolymers and Their Impact on the Mechanical and Reversible Adhesive Properties.

    PubMed

    Heinzmann, Christian; Salz, Ulrich; Moszner, Norbert; Fiore, Gina L; Weder, Christoph

    2015-06-24

    Hydrogen-bonded, side-chain-functionalized supramolecular poly(alkyl methacrylate)s were investigated as light- and temperature-responsive reversible adhesives that are useful for bonding and debonding on demand applications. Here, 2-hydroxyethyl methacrylate (HEMA) was functionalized with 2-ureido-4[1H]pyrimidinone (UPy) via a hexamethylenediisocyanate (HMDI) linker, to create a monomer (UPy-HMDI-HEMA) that serves to form supramolecular cross-links by way of forming quadruple hydrogen bonded dimers. UPy-HMDI-HEMA was copolymerized with either hexyl methacrylate or butyl methacrylate to create copolymers comprising 2.5, 5, or 10 mol % of the cross-linker. The mechanical properties of all (co)polymers were investigated with stress-strain experiments and dynamic mechanical analysis. Furthermore, the adhesive properties were studied at temperatures between 20 and 60 °C by testing single lap joints formed with stainless steel substrates. It was found that increasing the concentration of the UPy-HMDI-HEMA cross-linker leads to improved mechanical and adhesive properties at elevated temperatures. Concurrently, the reversibility of the bond formation remained unaffected, where rebonded samples displayed the same adhesive strength as regularly bonded samples. Debonding on demand abilities were also tested exemplarily for one copolymer, which for light-induced debonding experiments was blended with a UV-absorber that served as light-heat converter. Single lap joints were subjected to a constant force and heated or irradiated with UV light until debonding occurred. The necessary debonding temperature was comparable for direct heating and UV irradiation and varied between 28 and 82 °C, depending on the applied force. The latter also influenced the debonding time, which under the chosen conditions ranged from 30 s to 12 min. PMID:26043809

  3. Protective effect of chitosan oligosaccharide lactate against DNA double-strand breaks induced by a model methacrylate dental adhesive

    PubMed Central

    Szczepanska, Joanna; Pawlowska, Elzbieta; Synowiec, Ewelina; Czarny, Piotr; Rekas, Marek; Blasiak, Janusz; Szaflik, Jacek Pawel

    2011-01-01

    Summary Background Monomers of methacrylates used in restorative dentistry have been recently reported to induce DNA double-strand breaks (DSBs) in human gingival fibroblasts (HGFs) in vitro. Because such monomers may penetrate the pulp and oral cavity due to the incompleteness of polymerization and polymer degradation, they may induce a similar effect in vivo. DSBs are the most serious type of DNA damage and if misrepaired or not repaired may lead to mutation, cancer transformation and cell death. Therefore, the protection against DSBs induced by methacrylate monomers released from dental restorations is imperative. Material/Methods We examined the protective action of chitosan oligosaccharide lactate (ChOL) against cytotoxic and genotoxic effects induced by monomers of the model adhesive consisting of 55% bisphenol A-diglycidyl dimethacrylate (Bis-GMA) and 45% 2-hydroxyethyl methacrylate (HEMA). We evaluated the extent of DSBs by the neutral comet assay and the phosphorylation of the H2AX histone test. Results ChOL increased the viability of HGFs exposed to Bis-GMA/HEMA as assessed by flow cytometry. ChOL decreased the extent of DSBs induced by Bis-GMA/HEMA as evaluated by neutral comet assay and phosphorylation of the H2AX histone. ChOL did not change mechanical properties of the model adhesive, as checked by the shear bond test. Scanning electron microscopy revealed a better sealing of the dentinal microtubules in the presence of ChOL, which may protect pulp cells against the harmful action of the monomers. Conclusions ChOL can be considered as an additive to methacrylate-based dental materials to prevent DSBs induction, but further studies are needed on its formulation with the methacrylates. PMID:21804456

  4. Novel Nanocomposites of Poly(lauryl methacrylate)-Grafted Al2O3 Nanoparticles in LDPE.

    PubMed

    Cobo Sánchez, Carmen; Wåhlander, Martin; Taylor, Nathaniel; Fogelström, Linda; Malmström, Eva

    2015-11-25

    Aluminum oxide nanoparticles (NPs) were surface-modified by poly(lauryl methacrylate) (PLMA) using surface-initiated atom-transfer radical polymerization (SI-ATRP) of lauryl methacrylate. Nanocomposites were obtained by mixing the grafted NPs in a low-density polyethylene (LDPE) matrix in different ratios. First, the NPs were silanized with different aminosilanes, (3-aminopropyl)triethoxysilane, and 3-aminopropyl(diethoxy)methylsilane (APDMS). Subsequently, α-BiB, an initiator for SI-ATRP, was attached to the amino groups, showing higher immobilization ratios for APDMS and confirming that fewer self-condensation reactions between silanes took place. In a third step SI-ATRP of LMA at different times was performed to render PLMA-grafted NPs (NP-PLMAs), showing good control of the polymerization. Reactions were conducted for 20 to 60 min, obtaining a range of molecular weights between 23 000 and 83 000 g/mol, as confirmed by size-exclusion chromoatography of the cleaved grafts. Nanocomposites of NP-PLMAs at low loadings in LDPE were prepared by extrusion. At low loadings, 0.5 wt % of inorganic content, the second yield point, storage, and loss moduli increased significantly, suggesting an improved interphase as an effect of the PLMA grafts. These observations were also confirmed by an increase in transparency of the nanocomposite films. At higher loadings, 1 wt % of inorganics, the increasing amount of PLMA gave rise to the formation of small aggregates, which may explain the loss of mechanical properties. Finally, dielectric measurements were performed, showing a decrease in tan δ values for LDPE-NP-PLMAs, as compared to the nanocomposites containing unmodified NP, thus indicating an improved interphase between the NPs and LDPE.

  5. Characterization of glycidyl methacrylate – Crosslinked hyaluronan hydrogel scaffolds incorporating elastogenic hyaluronan oligomers

    PubMed Central

    Ibrahim, S.; Kothapalli, C.R.; Kang, Q.K.; Ramamurthi, A.

    2013-01-01

    Prior studies on two-dimensional cell cultures suggest that hyaluronic acid (HA) stimulates cell-mediated regeneration of extracellular matrix structures, specifically those containing elastin, though such biologic effects are dependent on HA fragment size. Towards being able to regenerate three-dimensional (3-D) elastic tissue constructs, the present paper studies photo-crosslinked hydrogels containing glycidyl methacrylate (GM)-derivatized bio-inert high molecular weight(HMW)HA (1 × 106 Da) and a bioactive HA oligomer mixture (HA-o: MW ~0.75 kDa). The mechanical (rheology, degradation) and physical (apparent crosslinking density, swelling ratio) properties of the gels varied as a function of incorporated HA oligomer content; however, overall, the mechanics of these hydrogels were too weak for vascular applications as stand-alone materials. Upon in vivo subcutaneous implantation, only a few inflammatory cells were evident around GM–HA gels, however their number increased as HA-o content within the gels increased, and the collagen I distribution was uniform. Smooth muscle cells (SMC) were encapsulated into GM hydrogels, and calcein acetoxymethyl detection revealed that the cells were able to endure twofold the level of UV exposure used to crosslink the gels. After 21 days of culture, SMC elastin production, measured by immunofluorescence quantification, showed HA-o to increase cellular deposition of elastic matrix twofold relative to HA-o-free GM–HAgels. These results demonstrate that cell response to HA/HA-o is not altered by their methacrylation and photo-crosslinking into a hydrogel, and that HA-o incorporation into cell-encapsulating hydrogel scaffolds can be useful for enhancing their production of elastic matrix structures in a 3-D space, important for regenerating elastic tissues. PMID:20709199

  6. Evaluation of three-dimensional biofilms on antibacterial bonding agents containing novel quaternary ammonium methacrylates

    PubMed Central

    Zhou, Han; Weir, Michael D; Antonucci, Joseph M; Schumacher, Gary E; Zhou, Xue-Dong; Xu, Hockin HK

    2014-01-01

    Antibacterial adhesives are promising to inhibit biofilms and secondary caries. The objectives of this study were to synthesize and incorporate quaternary ammonium methacrylates into adhesives, and investigate the alkyl chain length effects on three-dimensional biofilms adherent on adhesives for the first time. Six quaternary ammonium methacrylates with chain lengths of 3, 6, 9, 12, 16 and 18 were synthesized and incorporated into Scotchbond Multi-Purpose. Streptococcus mutans bacteria were cultured on resin to form biofilms. Confocal laser scanning microscopy was used to measure biofilm thickness, live/dead volumes and live-bacteria percentage vs. distance from resin surface. Biofilm thickness was the greatest for Scotchbond control; it decreased with increasing chain length, reaching a minimum at chain length 16. Live-biofilm volume had a similar trend. Dead-biofilm volume increased with increasing chain length. The adhesive with chain length 9 had 37% live bacteria near resin surface, but close to 100% live bacteria in the biofilm top section. For chain length 16, there were nearly 0% live bacteria throughout the three-dimensional biofilm. In conclusion, strong antibacterial activity was achieved by adding quaternary ammonium into adhesive, with biofilm thickness and live-biofilm volume decreasing as chain length was increased from 3 to 16. Antibacterial adhesives typically only inhibited bacteria close to its surface; however, adhesive with chain length 16 had mostly dead bacteria in the entire three-dimensional biofilm. Antibacterial adhesive with chain length 16 is promising to inhibit biofilms at the margins and combat secondary caries. PMID:24722581

  7. Methyl methacrylate levels in orthopedic surgery: comparison of two conventional vacuum mixing systems.

    PubMed

    Jelecevic, Jasmin; Maidanjuk, Stanislaw; Leithner, Andreas; Loewe, Kai; Kuehn, Klaus-Dieter

    2014-05-01

    Poly-methyl methacrylate bone cements contain methyl methacrylate (MMA), which is known for its sensitizing and toxic properties. Therefore, in most European countries and in the USA, guidelines or regulations exist for occupational exposures. The use of vacuum mixing systems can significantly reduce airborne MMA concentrations during bone setting. Our goal was to test two commonly used vacuum mixing systems (Palamix(®) and Optivac(®)) using Palacos(®) R bone cement for their effectiveness at preventing MMA vapor release in a series of standardized trials in a laboratory as well as in an operating theatre. MMA was quantified every second over a period of 3 min using a photoionization detector (MiniRAE(®) 3000) device positioned in the breathing area of the user. Significant differences in MMA mean vapor concentrations over 180 s were observed in the two experimental spaces, with the highest mean concentrations (7.61 and 7.98 ppm for Palamix(®) and Optivac(®), respectively) observed in a laboratory with nine air changes per hour and the lowest average concentrations (1.06 and 1.12 ppm for Palamix(®) and Optivac(®), respectively) in an operating theatre with laminar flow ventilation and 22 air changes per hour. No significant differences in overall MMA concentrations were found between the two vacuum mixing systems in either location. Though, differences were found between both systems during single mixing phases. Thus, typical handling of MMA in orthopedic procedures must be seen as not harmful as concentrations do not reach the short-term exposure limit of 100 ppm. Additionally, laminar airflow seems to have an influence on lowering MMA concentrations in operation theatres.

  8. Biomimetically-mineralized composite coatings on titanium functionalized with gelatin methacrylate hydrogels

    NASA Astrophysics Data System (ADS)

    Tan, Guoxin; Zhou, Lei; Ning, Chengyun; Tan, Ying; Ni, Guoxin; Liao, Jingwen; Yu, Peng; Chen, Xiaofeng

    2013-08-01

    Immobilizing organic-inorganic hybrid composites onto the implant surface is a promising strategy to improve host acceptance of the implant. The objective of this present study was to obtain a unique macroporous titanium-surface with the organic-mineral composite coatings consisting of gelatin methacrylate hydrogel (GelMA) and hydroxyapatite (HA). A 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) layer was first coated onto the titanium surface, and surface was then covalently functionalized with GelMA using a photochemical method. Mineralization of the GelMA coating on the titanium surface was subsequently carried out by a biomimetic method. After 3-day mineralization, a large number of mineral phases comprising spherical amorphous nanoparticles were found randomly deposited inside GelMA matrix. The resulting mineralized hydrogel composites exhibited a unique rough surface of macroporous structure. The structure of the prepared GelMA/HA composite coating was studied by field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectra (EDS), attenuated total refraction Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Water contact angle measurement revealed the hydrophilicity properties of composite coatings. GelMA/HA on titanium after the TMSPMA treatment is very stable when tested in vitro with a PBS solution at 37 °C, due to the role of TMSPMA as a molecular bridge. It was expected that the macroporous GelMA/HA composite coatings might potentially promote and accelerate titanium (Ti)-based implants osseointegration for bone repair and regeneration.

  9. Reinforcement of Dental Methacrylate with Glass Fiber after Heated Silane Application

    PubMed Central

    Fonseca, Rodrigo Borges; de Paula, Marcella Silva; Favarão, Isabella Negro; Kasuya, Amanda Vessoni Barbosa; de Almeida, Letícia Nunes; Mendes, Gustavo Adolfo Martins; Carlo, Hugo Lemes

    2014-01-01

    This study evaluated the influence of silane heat treatment and glass fiber fabrication type, industrially treated (I) or pure (P), on flexural and compressive strength of methacrylate resin bars (BISGMA/TEGDMA, 50/50%). Six groups (n = 10) were created: I-sil: I/silanated; P-sil: P-silanated; I-sil/heat: I/silanated heated to 100°; P-sil/heat: P/silanated heated to 100°; (I: I/not silanated; and P: P/not silanated. Specimens were prepared for flexural strength (10 × 2 × 1 mm) and for compressive strength 9.5 × 5.5 × 3 mm) and tested at 0.5 mm/min. Statistical analysis demonstrated the following for flexural strength (P < 0.05): I-sil: 155.89 ± 45.27BC; P-sil: 155.89 ± 45.27BC; I-sil/heat: 130.20 ± 22.11C; P-sil/heat: 169.86 ± 50.29AB; I: 131.87 ± 15.86C. For compressive strength, the following are demonstrated: I-sil: 1367.25 ± 188.77ab; P-sil: 867.61 ± 102.76d; I-sil/heat: 1162.98 ± 222.07c; P-sil/heat: 1499.35 ± 339.06a; and I: 1245.78 ± 211.16bc. Due to the impossibility of incorporating the stipulated amount of fiber, P group was excluded. Glass fiber treatment with heated silane enhanced flexural and compressive strength of a reinforced dental methacrylate. PMID:24967361

  10. [Analysis of the character of film decomposition of methyl methacrylate (MMA) coated urea by infrared spectrum].

    PubMed

    Li, Dong-po; Wu, Zhi-jie; Liang, Cheng-hua; Chen, Li-jun; Zhang, Yu-lan; Nie, Yan-xi

    2012-03-01

    The degradability characteristics of film with 4 kinds of methyl methacrylate coated urea amended with inhibitors were analyzed by FITR, which was purposed to supply theoretical basis for applying the FITR analysis method to film decomposition and methyl methacrylate coated urea fertilizers on farming. The result showed that the chemical component, molecule structure and material form of the membrane were not changed because of adding different inhibitors to urea. the main peaks of expressing film degradation process were brought by the -C-H of CH3 & CH2, -OH, C-O, C-C, C-O-C, C=O, C=C flexing vibrancy in asymmetry and symmetry in 3 479-3 195, 2 993--2 873, 1 741-1 564, 1 461-925 and 850-650 cm(-1). The peak value changed from smooth to tip, and from width to narrow caused by chemical structural transform of film The infrared spectrum of 4 kinds of fertilizers was not different remarkably before 60 days, and the film was slowly degraded. But degradation of the film was expedited after 60 days, it was most quickened at 120 day, and the decomposition rate of film was decreased at 310 day. The substantiality change of film in main molecule structure of 4 kinds of fertilizers didn't happen in 310 days. The main component of film materials was degraded most slowly in brown soil. The speed of film degradation wasn't heavily impacted by different inhibitors. The characteristic of film degradation may be monitored entirely by infrared spectrum. The degradation dynamic, chemical structure change, degradation speed difference of the film could be represented through infrared spectrum. PMID:22582622

  11. Robust naphthyl methacrylate monolithic column for high performance liquid chromatography of a wide range of solutes.

    PubMed

    Jonnada, Murthy; El Rassi, Ziad

    2015-08-28

    An organic monolithic column based on the co-polymerization of 2-naphthyl methacrylate (NAPM) as the functional monomer and trimethylolpropane trimethacrylate (TRIM) as the crosslinker was introduced for high performance reversed-phase liquid chromatography (RPC). The co-polymerization was performed in situ in a stainless steel column of 4.6mm i.d. in the presence of a ternary porogen consisting of 1-dodecanol and cyclohexanol. This monolithic column (referred to as naphthyl methacrylate monolithic column or NMM column) showed high mechanical stability at relatively high mobile phase flow velocity indicating that the column has excellent hydrodynamic characteristics. To characterize the NMM column, different probe molecules including alkyl benzenes, and aniline, benzene, toluene and phenol derivatives were chromatographed on the column and the results in terms of k, selectivity and plate counts were compared to those obtained on an octadecyl silica (ODS) column in order to assess the presence of π-π and hydrophobic interactions on the NMM column under otherwise the same elution conditions. The NMM column offered additional π-π interactions with aromatic molecules in addition to hydrophobic interactions under RPC elution conditions. Run-to-run and column-to-column reproducibility of solute k values were evaluated, and percent relative standard deviation of <1% and ∼2-3.5%, respectively, were obtained. Six standard proteins were readily separated on the NMM column using shallow (30min at 1.0mL/min), steep (10min at 1.0mL/min) and ultra steep (1min at 3.0mL/min) linear gradient elution at increasing ACN concentration in the mobile phase using a 10cm×4.6mm i.d. column in case of shallow and steep linear gradients and a 3cm×4.6mm i.d. column for ultra steep linear gradient.

  12. [Analysis of the character of film decomposition of methyl methacrylate (MMA) coated urea by infrared spectrum].

    PubMed

    Li, Dong-po; Wu, Zhi-jie; Liang, Cheng-hua; Chen, Li-jun; Zhang, Yu-lan; Nie, Yan-xi

    2012-03-01

    The degradability characteristics of film with 4 kinds of methyl methacrylate coated urea amended with inhibitors were analyzed by FITR, which was purposed to supply theoretical basis for applying the FITR analysis method to film decomposition and methyl methacrylate coated urea fertilizers on farming. The result showed that the chemical component, molecule structure and material form of the membrane were not changed because of adding different inhibitors to urea. the main peaks of expressing film degradation process were brought by the -C-H of CH3 & CH2, -OH, C-O, C-C, C-O-C, C=O, C=C flexing vibrancy in asymmetry and symmetry in 3 479-3 195, 2 993--2 873, 1 741-1 564, 1 461-925 and 850-650 cm(-1). The peak value changed from smooth to tip, and from width to narrow caused by chemical structural transform of film The infrared spectrum of 4 kinds of fertilizers was not different remarkably before 60 days, and the film was slowly degraded. But degradation of the film was expedited after 60 days, it was most quickened at 120 day, and the decomposition rate of film was decreased at 310 day. The substantiality change of film in main molecule structure of 4 kinds of fertilizers didn't happen in 310 days. The main component of film materials was degraded most slowly in brown soil. The speed of film degradation wasn't heavily impacted by different inhibitors. The characteristic of film degradation may be monitored entirely by infrared spectrum. The degradation dynamic, chemical structure change, degradation speed difference of the film could be represented through infrared spectrum.

  13. Comparison of human mesenchymal stem cells proliferation and differentiation on poly(methyl methacrylate) bone cements with and without mineralized collagen incorporation.

    PubMed

    Wu, Jingjing; Xu, Suju; Qiu, Zhiye; Liu, Peng; Liu, Huiying; Yu, Xiang; Cui, Fu-Zhai; Chunhua, Zhao Robert

    2016-01-01

    Poly(methyl methacrylate) bone cement is widely used in vertebroplasty, joint replacement surgery, and other orthopaedic surgeries, while it also exposed many problems on mechanical property and biocompatibility. Better performance in mechanical match and bone integration is highly desirable. Recently, there reported that incorporation of mineralized collagen into poly(methyl methacrylate) showed positive results in mechanical property and osteointegration ability in vivo. In the present study, we focused on the comparison of osteogenic behavior between mineralized collagen incorporated in poly(methyl methacrylate) and poly(methyl methacrylate). Human marrow mesenchymal stem cells are used in this experiment. Adhesion and proliferation were used to characterize biocompatibility. Activity of alkaline phosphatase was used to assess the differentiation of human marrow mesenchymal stem cells into osteoblasts. Real-time PCR was performed to detect the expression of osteoblast-related markers at messenger RNA level. The results show that osteogenic differentiation on mineralized collagen incorporated in poly(methyl methacrylate) bone cement is more than two times higher than that of poly(methyl methacrylate) after culturing for 21 days. Thus, important mechanism on mineralized collagen incorporation increasing the osteogenetic ability of poly(methyl methacrylate) bone cement may be understood in this concern.

  14. Specialty polymeric membranes. 8: Separation of benzene from benzene/cyclohexane mixtures with nylon 6-graft-poly(butyl methacrylate) membranes

    SciTech Connect

    Yoshikawa, Masakazu; Tsubouchi, Keisuke; Kitao, Toshio

    1999-02-01

    A novel pervaporation membrane was prepared by radical graft polymerization of butyl methacrylate onto nylon 6. The permselectivity toward benzene was increased by the introduction of poly(butyl methacrylate) onto a nylon 6 membrane. From pervaporation and sorption experiments, it was shown that the introduction of poly(butyl methacrylate) onto a nylon 6 membrane leads to the enhancement of permselectivity toward benzene. The solubility data for benzene were described by a combination of simple sorption and specific sorption, while cyclohexane solubility was described by simple sorption.

  15. Synthesis of comb-like copolymers from renewable resources: Itaconic anhydride, stearyl methacrylate and lactic acid

    NASA Astrophysics Data System (ADS)

    Shang, Shurui

    The synthesis and properties of comb-like copolymers and ionomers derived from renewable resources: itaconic anhydride (ITA), stearyl methacrylate (SM) and lactic acid (LA) are described. The copolymers based on ITA and SM (ITA-SM) were nearly random with a slight alternating tendency. The copolymers exhibited a nanophase-separated morphology, with the stearate side-chains forming a bilayer, semi-crystalline structure. The crystalline side-chains suppressed molecular motion of the main-chain, so that a glass transition temperature (Tg) was not resolved unless the ITA concentration was sufficiently high so that Tg > the melting point (Tm). The softening point and modulus of the copolymers increased with the increasing ITA concentration, but the thermal stability decreased. The ITA moiety along the main chain of the copolymers was neutralized with metal acetates to produce Na-, Ca- and Zn- random ionomers with comb-like architectures. In general, the incorporation of the ionic groups increased the Tg and suppressed the crystallinity of the side-chain packing. Ionomers with high SM side-chain density had two competing driving forces for self-assembled nano-phase separation: ionic aggregation and side-chain crystalline packing. Upon neutralization, a morphological transition from semi-crystalline lamella to spherical ionic aggregation was observed by small angle X-ray scattering (SAXS) analysis and transmission electron microscopy (TEM). Thermomechanical analysis revealed an increasing resistance to penetration deformation with an increasing degree of neutralization and an apparent rubbery plateau was observed above Tg. A controlled transesterification of PLA in glassware was an effective way to prepare a methacrylate functionalized PLA macromonomer with controlled molecular weight, which was used to synthesize a variety of copolymers. The copolymerization of this functionalized PLA macromonomer with ITA totally suppressed the side-chain crystallinity for the PLA chain

  16. Polymer electrolyte based on crosslinked poly(glycidyl methacrylate) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide

    SciTech Connect

    Fei, Beatrice Wong Chui; Hanifah, Sharina Abu; Ahmad, Azizan; Hassan, Nur Hasyareeda

    2015-09-25

    Polymer electrolytes based on crosslinked poly(glycidyl methacrylate) as polymer host and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimTFSI) as incorporated salt were prepared by in-situ photopolymerization technique. The complexes with different mass ratio of glycidyl methacrylate (GMA) monomer to BmimTFSI were investigated. The ionic conductivity of the polymer electrolyte was increased and reach the highest value of 7.50 × 10{sup −4} S cm{sup −1} at the ratio of 3:7 (GMA: BmimTFSI). The interaction between the polymer host and ionic liquid was proved by Attenuated Total Reflectance-Fourier Transformation Infra-Red Spectroscopy (ATR-FTIR). Meanwhile, the X-ray diffraction analysis shows the amorphousity of the polymer electrolyte film increase with the ionic liquid ratio.

  17. Synthesis and properties of poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid)/PbS hybrid composite

    SciTech Connect

    Preda, N.; Rusen, E.; Musuc, A.; Enculescu, M.; Matei, E.; Marculescu, B.; Fruth, V.; Enculescu, I.

    2010-08-15

    The synthesis of a new hybrid composite based on PbS nanoparticles and poly(methyl methacrylate-2-acrylamido-2-methylpropane sulfonic acid) [P(MMA-AMPSA)] copolymer is reported. The chemical synthesis consists in two steps: (i) a surfactant-free emulsion copolymerization between methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid and (ii) the generation of PbS particles in the presence of the P(MMA-AMPSA) latex, from the reaction between lead nitrate and thiourea. The composite was studied by scanning electron microscopy (SEM), X-ray diffraction, FTIR spectroscopy, thermogravimetric analysis and differential scanning calorimetry. The microstructure observed using SEM proves that the PbS nanoparticles are well dispersed in the copolymer matrix. The X-ray diffraction measurements demonstrate that the PbS nanoparticles have a cubic rock salt structure. It was also found that the inorganic semiconductor nanoparticles improve the thermal stability of the copolymer matrix.

  18. Triblock copolyampholytes from 5-(N,N-dimethyl amino)isoprene styrene, and methacrylic acid: Synthesis and solution properties

    NASA Astrophysics Data System (ADS)

    Bieringer, R.; Abetz, V.; Müller, A. H. E.

    ABC triblock copolymers of the type poly[5-(N,N-dimethyl amino)isoprene]-block-polystyrene-block-poly(tert-butyl methacrylate) (AiST) were synthesized and hydrolyzed to yield poly[5-(N,N-dimethyl amino)isoprene]-block-polystyrene-block-poly(methacrylic acid) (AiSA) triblock copolyampholytes. Due to a complex solubility behavior the solution properties of these materials had to be investigated in THF/water solvent mixtures. Potentiometric titrations of AiSA triblock copolyampholytes showed two inflection points with the A block being deprotonated prior to the Ai hydrochloride block thus forming a polyzwitterion at the isoelectric point (iep). The aggregation behavior was studied by dynamic light scattering (DLS) and freeze-fracture/transmission electron microscopy (TEM). Large vesicular structures with almost pH-independent radii were observed.

  19. Multifunctional copolymer coating of polyethylene glycol, glycidyl methacrylate, and REDV to enhance the selectivity of endothelial cells.

    PubMed

    Wei, Yu; Zhang, Jingxun; Li, Haolie; Zhang, Li; Bi, Hong

    2015-01-01

    Multifunctional polymer coatings have potential applications in biomaterials. These coatings possess reactive functional groups for the immobilization of specific biological factors that can influence cellular behavior. These coatings also display low nonspecific protein adsorption. In this study, we prepared a multifunctional polymer coating through the deposition of random copolymers of poly(ethylene glycol) methacrylate (PEGMA) and glycidyl methacrylate (GMA) to prevent nonspecific attachment and enable the covalence of Arg-Glu-Asp-Val (REDV) peptide with endothelial cells (ECs) selectivity. Coatings were characterized by X-ray photoelectron spectroscopy (XPS). The adhesion and proliferation of ECs and smooth muscle cells (SMCs) onto the REDV-modified surface were investigated to understand the synergistic action of antifouling PEG and EC selective REDV peptide conjugated GMA. The copolymers containing GMA and PEG groups are very useful as a multifunctional coating material with anti-fouling and ECs specific adhesion for implant materials surface modification. PMID:26381476

  20. Methacrylated monosaccharides as the modifiers for carbochain polymers: Synthesis, mechanical/thermal properties and biodegradability of hybrids

    NASA Astrophysics Data System (ADS)

    Yakushev, P.; Bershtein, V.; Bukowska-Śluz, I.; Sobiesiak, M.; Gawdzik, B.

    2016-05-01

    Methacrylated derivatives of glucose (MGLU) and galactose (MGAL) were synthesized by the procedure described by Vogel, and their copolymers with methyl methacrylate (MMA) and MMA/N-vinyl pyrrolidone (MMA/NVP) (1:1) mixture were obtained with the aim to modify some properties of carbochain polymers, in particular to generate their biodegradability. These hybrids of synthetic and natural products, with 10, 20 or 30 wt. % modifiers, were characterized by DMA and TGA methods and in the biodegradation tests. Increasing Tg values by 20-30°C was registered in all cases whereas thermal stability was improved only for PMMA due to modification. On the contrary, only for hybrids based on hygroscopic MMA/NVP copolymer the essential biodegradability could be generated.

  1. Nanomechanical properties of solvent cast polystyrene and poly(methyl methacrylate) polymer blends and self-assembled block copolymers

    NASA Astrophysics Data System (ADS)

    Lorenzoni, Matteo; Evangelio, Laura; Nicolet, Célia; Navarro, Christophe; San Paulo, Alvaro; Rius, Gemma; Pérez-Murano, Francesc

    2015-07-01

    The nanomechanical properties of solvent-cast polymer thin films have been investigated using PeakForce™ Quantitative Nanomechanical Mapping. The samples consisted of films of polystyrene (PS) and poly(methyl methacrylate) (PMMA) obtained after the dewetting of toluene solution on a polymeric brush layer. Additionally, we have probed the mechanical properties of poly(styrene-b-methyl methacrylate) block copolymers (BCP) as randomly oriented thin films. The probed films have a critical thickness <50 nm and present features to be resolved <42 nm. The Young's modulus values obtained through several nanoindentation experiments present a good agreement with previous literature, suggesting that the PeakForce™ technique could be crucial for BCP investigations, e.g., as a predictor of the mechanical stability of the different phases.

  2. A simple sonochemical method for fabricating poly(methyl methacrylate)/stearic acid phase change energy storage nanocapsules.

    PubMed

    Wang, Guxia; Xu, Weibing; Hou, Qian; Guo, Shengwei

    2015-11-01

    In this study, stearic acid suitable for thermal energy storage applications was nanoencapsulated in a poly(methyl methacrylate) shell. The nanocapsules were prepared using a simple ultrasonically initiated in situ polymerization method. The morphology and particle size of the poly(methyl methacrylate)/stearic acid phase change energy storage nanocapsules (PMS-PCESNs) were analyzed using transmission electron microscopy, scanning electron microscopy, atomic force microscopy and dynamic light scattering. The latent heat storage capacities of stearic acid and the PMS-PCESNs were determined using differential scanning calorimetry. The chemical composition of the nanocapsules was characterized using Fourier transform infrared spectroscopy. All of the results show that the PMS-PCESNs were synthesized successfully and that the latent heat storage capacity and encapsulation efficiency were 155.6 J/g and 83.0%, respectively, and the diameter of each nanocapsule was 80-90 nm.

  3. ESR study of the radiolysis of cellobiose, cellulose-containing materials, and their mixtures with methyl methacrylate

    SciTech Connect

    Kozlova, E.Y.; Shostenko, A.G.; Ermolaev, S.V.

    1995-01-01

    The ESR spectra of {gamma}-irradiated cellobiose, paper waste, and cellulose extracted from paper waste and waste pulp sludge were analyzed. The kinetics of formation and decay of cellobiose radicals were investigated, and the radiation-chemical yields of the radicals formed in cellulose-containing materials were calculated. The ESR spectra of cellobiose irradiated in the presence of methyl methacrylate (MMA) were obtained. A probable mechanism of MMA grafting onto cellulose-containing matrices is considered.

  4. A poly(alkyl methacrylate-divinylbenzene-vinylbenzyl trimethylammonium chloride) monolithic column for solid-phase microextraction.

    PubMed

    Liu, Wan-Ling; Lirio, Stephen; Yang, Yicong; Wu, Lin-Tai; Hsiao, Shu-Ying; Huang, Hsi-Ya

    2015-05-22

    In this study, an organic polymer monolithic columns, which were prepared via in situ polymerization of alkyl methacrylate-ester (AMA), divinylbenzene (DVB) and vinylbenzyl trimethylammonium chloride (VBTA, charged monomer), were developed as adsorbent for solid-phase microextraction (SPME). Different parameters affecting the extraction efficiency for nine (9) non-steroidal anti-inflammatory drugs (NSAIDs) such as the ratio of the stearyl methacrylate (SMA) to DVB monomer, column length, sample pH, extraction flow rate and desorption solvent were investigated to obtain the optimal SPME condition. Also, the permeability for each poly(AMA-DVB-VBTA) monolithic column was investigated by adding porogenic solvent (poly(ethylene glycol), PEG). Using the optimized condition, a series of AMA-based poly(AMA-DVB-VBTA) monolith columns were developed to determine the effect the extraction efficiency of NSAIDs by varying the alkyl chain length of the methacrylate ester (methyl-, butyl-, octyl-, or lauryl-methacrylate; (MMA, BMA, OMA, LMA)). Results showed that decreasing the AMA chain length increases the extraction efficiency of some NSAIDs (i.e. sulindac (sul), naproxen (nap), ketoprofen (ket) and indomethacin (idm)). Among the poly(AMA-DVB-VBTA) monolithic columns, poly(BMA-DVB-VBTA) showed a highly repeatable extraction efficiency for NSAIDs with recoveries ranging from 85.0 to 100.2% with relative standard deviation (RSD) less than 6.8% (n=3). The poly(BMA-DVB-VBTA) can also be reused for at least 50 times without any significant effect in extraction efficiency for NSAIDs. Finally, using the established conditions, the poly(BMA-DVB-VBTA) was used to extract trace-level NSAIDs (100μgL(-1)) in river water with good recoveries ranging from 75.8 to 90.8% (RSD<14.9%).

  5. Evaluation of Microleakage of Silorane and Methacrylate Based Composite Materials in Class I Restorations by Using Two Different Bonding Techniques

    PubMed Central

    Alshetili, Mohsen S; Aldeyab, Sultan S

    2015-01-01

    Background: To evaluate the microleakage of silorane-based composite material (Filtek P90) with that of two homologous methacrylate-based composites materials (Filtek Z250 and Filtek Z250 XT), by using two different bonding techniques. Materials and Methods: Sixty extracted human maxillary first premolars prepared for standardized Class I cavities (4 mm × 2 mm × 2 mm) were randomly divided into three groups. Group A (n = 20) was filled with Filtek Z250 (Methacrylate) using single bond universal total etching technique, Group B (n = 20) was filled with Filtek Z250 XT (Methacrylate) using single bond universal self-etching technique and Group C (n = 20) restored with Filtek P90 (Silorane) with dedicated two-step self-etching prime and bond adhesive system (P90 system adhesive). Teeth were subjected to thermocycling regime (500×, 5-55°C), and dye penetration by immersing in 2% methylene blue for 24 h. Tooth sectioning was performed, and extent of the dye penetration was scored based on dye penetration scale to evaluate the microleakage. Statistical analysis included descriptive statistics and inferential statistics of Kruskal–Wallis test to compare the mean ranks between groups. Results: There was no significant difference observed for microleakage among the three composite materials tested in the present study. However, the cavities restored with silorane (Filtek P90) based composite displayed higher microleakage than the Filtek Z250, Z250 XT. Conclusion: All the restorative systems tested in this study exhibited microleakage, but the silorane technology showed more microleakage when compared to the methacrylate-based composite systems. PMID:26668473

  6. Bioinspired Hydroxyapatite/Poly(methyl methacrylate) Composite with a Nacre-Mimetic Architecture by a Bidirectional Freezing Method.

    PubMed

    Bai, Hao; Walsh, Flynn; Gludovatz, Bernd; Delattre, Benjamin; Huang, Caili; Chen, Yuan; Tomsia, Antoni P; Ritchie, Robert O

    2016-01-01

    Using a bidirectional freezing technique, combined with uniaxial pressing and in situ polymerization, "nacre-mimetic" hydroxyapatite/poly(methyl methacrylate) (PMMA) composites are developed by processing large-scale aligned lamellar ceramic scaffolds. Structural and mechanical characterization shows "brick-and-mortar" structures, akin to nacre, with interesting combinations of strength, stiffness, and work of fracture, which provide a pathway to making strong and tough lightweight materials.

  7. Degree of conversion and leached monomers of urethane dimethacrylate-hydroxypropyl methacrylate-based dental resin systems.

    PubMed

    Zhang, Meng; Puska, Mervi A; Botelho, Michael G; Säilynoja, Eija S; Matinlinna, Jukka P

    2016-01-01

    The degree of conversion (DC) and monomer leaching of three experimental urethane dimethacrylate (UEDMA)-hydroxypropyl methacrylate (HPMA)-based resin systems were studied. Three experimental resins (E1: 70.6 wt% UEDMA + 27.4 wt% HPMA, E2: 80.6 wt% UEDMA + 17.4 wt% HPMA, E3: 90.6 wt% UEDMA + 7.4 wt% HPMA) and one control resin [C: 70.6 wt% bis-phenol A glycidyl methacrylate (bis-GMA) + 27.4 wt% methyl methacrylate (MMA)] were prepared. For the DC test, cylindrical specimens [1.5 mm (h) × 6 mm (d)] were scanned with an ATR-FTIR instrument before and after light-curing (n = 5). For the monomer leaching test, block-shaped specimens [5.67 mm (l) × 2.00 mm (w) × 2.00 mm (h)] were light-cured (n = 6), stored in a 75% ethanol:water solution for 3 days, and then analyzed with HPLC. The UEDMA-HPMA-based experimental groups showed higher DC (62-78%) than the bis-GMA-MMA-based control group (58-66%), and the DC decreased as the UEDMA content increased (P < 0.05). Amongst the four groups, E3 exhibited the lowest leaching of both mono methacrylate (0.1% HPMA) and dimethacrylate (<0.043% UEDMA) monomers after 30 or 40 s of curing. The UEDMA-HPMA-based resins, therefore, exhibited higher DC and less monomer leaching compared to the bis-GMA-MMA-based resin. (J Oral Sci 58, 15-22, 2016). PMID:27021535

  8. Bioinspired Hydroxyapatite/Poly(methyl methacrylate) Composite with a Nacre-Mimetic Architecture by a Bidirectional Freezing Method.

    PubMed

    Bai, Hao; Walsh, Flynn; Gludovatz, Bernd; Delattre, Benjamin; Huang, Caili; Chen, Yuan; Tomsia, Antoni P; Ritchie, Robert O

    2016-01-01

    Using a bidirectional freezing technique, combined with uniaxial pressing and in situ polymerization, "nacre-mimetic" hydroxyapatite/poly(methyl methacrylate) (PMMA) composites are developed by processing large-scale aligned lamellar ceramic scaffolds. Structural and mechanical characterization shows "brick-and-mortar" structures, akin to nacre, with interesting combinations of strength, stiffness, and work of fracture, which provide a pathway to making strong and tough lightweight materials. PMID:26554760

  9. Degree of conversion and leached monomers of urethane dimethacrylate-hydroxypropyl methacrylate-based dental resin systems.

    PubMed

    Zhang, Meng; Puska, Mervi A; Botelho, Michael G; Säilynoja, Eija S; Matinlinna, Jukka P

    2016-01-01

    The degree of conversion (DC) and monomer leaching of three experimental urethane dimethacrylate (UEDMA)-hydroxypropyl methacrylate (HPMA)-based resin systems were studied. Three experimental resins (E1: 70.6 wt% UEDMA + 27.4 wt% HPMA, E2: 80.6 wt% UEDMA + 17.4 wt% HPMA, E3: 90.6 wt% UEDMA + 7.4 wt% HPMA) and one control resin [C: 70.6 wt% bis-phenol A glycidyl methacrylate (bis-GMA) + 27.4 wt% methyl methacrylate (MMA)] were prepared. For the DC test, cylindrical specimens [1.5 mm (h) × 6 mm (d)] were scanned with an ATR-FTIR instrument before and after light-curing (n = 5). For the monomer leaching test, block-shaped specimens [5.67 mm (l) × 2.00 mm (w) × 2.00 mm (h)] were light-cured (n = 6), stored in a 75% ethanol:water solution for 3 days, and then analyzed with HPLC. The UEDMA-HPMA-based experimental groups showed higher DC (62-78%) than the bis-GMA-MMA-based control group (58-66%), and the DC decreased as the UEDMA content increased (P < 0.05). Amongst the four groups, E3 exhibited the lowest leaching of both mono methacrylate (0.1% HPMA) and dimethacrylate (<0.043% UEDMA) monomers after 30 or 40 s of curing. The UEDMA-HPMA-based resins, therefore, exhibited higher DC and less monomer leaching compared to the bis-GMA-MMA-based resin. (J Oral Sci 58, 15-22, 2016).

  10. Hydrogel-elastomer composite biomaterials: 2. Effects of aging methacrylated gelatin solutions on the preparation and physical properties of interpenetrating polymer networks.

    PubMed

    Peng, Henry T; Mok, Michelle; Martineau, Lucie; Shek, Pang N

    2007-06-01

    This study was conducted to understand the effects of aging methacrylated gelatin solutions on the properties of gelatin-HydroThane Interpenetrating Polymer Network (IPN) films. The latter were prepared from methacrylated gelatin solutions that were either freshly made or stored at different concentrations and temperatures for various periods. The morphology, swelling stability and mechanical properties of the IPNs were then accordingly characterized. The IPNs prepared with aged solutions showed a reduced phase separation; changed from a network-like structure to a continuous phase structure; and demonstrated higher swelling stabilities and higher elasticity under optimal aging conditions, compared to the IPN prepared with a fresh methacrylated gelatin solution. An increase in viscosity and a change in phase transition of aged methacrylated gelatin solutions were also observed, presumably due to the physical structuring of methacrylated gelatin chains (e.g., by the formation of a helix structure), thus altering the resulting IPN characteristics. A better understanding of the effects of aging methacrylated gelatin solution on the formation and properties of gelatin-HydroThane IPNs should enable us to further develop our composite biomaterials for different dressing applications.

  11. Variation in the chromatographic, material, and chemical characteristics of methacrylate-based polymer monoliths during photoinitiated low-temperature polymerization.

    PubMed

    Kobayashi, Ayumi; Nakaza, Takuya; Hirano, Tomohiko; Kitagawa, Shinya; Ohtani, Hajime

    2016-07-01

    Both the separation behavior and the structure of a polymer monolith column depends on both the reaction solution composition and the polymerization conditions. In photoinitiated low-temperature polymerization, polymerization temperature, irradiation intensity, and polymerization time were key factors to control the monolith characteristics. In this study, the effect of polymerization time on the chromatographic, material, and chemical characteristics of poly(butyl methacrylate-co-ethylene dimethacrylate) monoliths was studied using pyrolysis-gas chromatography, Raman spectroscopy, inverse size exclusion chromatography, scanning electron microscopy, and chromatographic methods. Both butyl methacrylate and ethylene dimethacrylate monomers were incorporated into the monolith as the polymerization time increased, and it resulted in increases in both the flow resistance (decrease in both permeability and total/through pore porosities) and retention factors. The longer polymerization time led to lower relative amounts of free methacrylate functional groups in the monolith, i.e. cross-linking was enhanced. The increase of the polymerization time from 8 to 12 min significantly reduced the separation efficiency for the retained analyte, whereas an increase in the fraction of the mesoporosity was observed. PMID:27129896

  12. Effect of methacrylic acid beads on the sonic hedgehog signaling pathway and macrophage polarization in a subcutaneous injection mouse model.

    PubMed

    Lisovsky, Alexandra; Zhang, David K Y; Sefton, Michael V

    2016-08-01

    Poly(methacrylic acid-co-methyl methacrylate) (MAA) beads promote a vascular regenerative response when used in diabetic wound healing. Previous studies reported that MAA beads modulated the expression of sonic hedgehog (Shh) and inflammation related genes in diabetic wounds. The aim of this work was to follow up on these observations in a subcutaneous injection model to study the host response in the absence of the confounding factors of diabetic wound healing. In this model, MAA beads improved vascularization in healthy mice of both sexes compared to control poly(methyl methacrylate) (MM) beads, with a stronger effect seen in males than females. MAA-induced vessels were perfusable, as evidenced from the CLARITY-processed images. In Shh-Cre-eGFP/Ptch1-LacZ non-diabetic transgenic mice, the increased vessel formation was accompanied by a higher density of cells expressing GFP (Shh) and β-Gal (patched 1, Ptch1) suggesting MAA enhanced the activation of the Shh pathway. Ptch1 is the Shh receptor and a target of the pathway. MAA beads also modulated the inflammatory cell infiltrate in CD1 mice: more neutrophils and more macrophages were noted with MAA relative to MM beads at days 1 and 7, respectively. In addition, MAA beads biased macrophages towards a MHCII-CD206+ ("M2") polarization state. This study suggests that the Shh pathway and an altered inflammatory response are two elements of the complex mechanism whereby MAA-based biomaterials effect vascular regeneration. PMID:27264502

  13. Crosslinkable fumed silica-based nanocomposite electrolytes: role of methacrylate monomer in formation of crosslinked silica network

    NASA Astrophysics Data System (ADS)

    Yerian, Jeffrey A.; Khan, Saad A.; Fedkiw, Peter S.

    The electrochemical and rheological properties of composite polymer electrolytes (CPEs) based on fumed silica with tethered crosslinkable groups are reported. These silica nanoparticles are dispersed in electrolytes consisting of poly(ethylene glycol) dimethyl ether (PEGdm)+lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) to which various methacrylate monomers, such as methyl (MMA), ethyl (EMA), butyl (BMA), n-hexyl (HMA), and n-dodecyl (DMA) methacrylate, are added. The methacrylate monomer facilitates creation of chemical crosslinks between fumed silica particles and formation of a crosslinked network. In this study, the effects of concentration and alkyl chain length of the monomers on conductivity, dynamic rheology, open-circuit interfacial stability, and cell voltage in lithium-lithium cell cycling are examined. Increasing the length of the monomer alkyl chain enhances both conductivity and elastic modulus of the crosslinked CPE. In contrast, increasing monomer concentration results in higher elastic modulus, but reduced conductivity. Lithium-lithium cell cycling and open-circuit interfacial stability results did not correlate with alkyl chain length. That is, for the lithium-lithium cycling studies, all crosslinked samples exhibit higher half-cycle voltage compared to non-crosslinked samples; however, the open-circuit interfacial stability of CPEs containing BMA and HMA exhibit improved stability compared to the other monomers and the CPE without monomer.

  14. Theoretical and experimental research on the self-assembled system of molecularly imprinted polymers formed by salbutamol and methacrylic acid.

    PubMed

    Jun-Bo, Liu; Yang, Shi; Shan-Shan, Tang; Rui-Fa, Jin

    2015-03-01

    The quantum chemical method was applied for screening functional monomers in the rational design of salbutamol-imprinted polymers. Salbutamol was the template molecule, and methacrylic acid was the single functional monomer. The LC-WPBE/6-31G(d,p) method was used to investigate the geometry optimization, active sites, natural bond orbital charges, binding energies of the imprinted molecule, and solvation energy. The mechanism of action between salbutamol and methacrylic acid was also discussed. The theoretical results show that salbutamol interacts with functional monomers by hydrogen bonds, and the salbutamol-imprinted polymers with a ratio of 1:4 (salbutamol/methacrylic acid) in acetonitrile had the highest stability. The salbutamol-imprinted polymers were prepared by precipitation polymerization. The experimental results indicated that the maximum adsorption capacity for salbutamol toward molecularly imprinted polymers was 7.33 mg/g, and the molecularly imprinted polymers had a higher selectivity for salbutamol than for norepinephrine and terbutaline sulfate. Herein, the studies can provide theoretical and experimental references for the salbutamol molecular imprinted system.

  15. A comparative study of the decomposition of pig carcasses in a methyl methacrylate box and open air conditions.

    PubMed

    Li, Liangliang; Wang, Jiangfeng; Wang, Yu

    2016-08-01

    Analysis of the process of decomposition is essential in establishing the postmortem interval. However, despite the fact that insects are important players in body decomposition, their exact function within the decay process is still unclear. There is also limited knowledge as to how the decomposition process occurs in the absence of insects. In the present study, we compared the decomposition of a pig carcass in open air with that of one placed in a methyl methacrylate box to prevent insect contact. The pig carcass in the methyl methacrylate box was in the fresh stage for 1 day, the bloated stage from 2 d to 11 d, and underwent deflated decay from 12 d. In contrast, the pig carcass in open air went through the fresh, bloated, active decay and post-decay stages; and 22.3 h (0.93 d), 62.47 h (2.60 d), 123.63 h (5.15 d) and 246.5 h (10.27 d) following the start of the experiment respectively, prior to entering the skeletonization stage. A large amount of soft tissue were remained on the pig carcass in the methyl methacrylate box on 26 d, while only scattered bones remained on the pig carcass in open air. The results indicate that insects greatly accelerate the decomposition process.

  16. Homogeneously aligned liquid crystal molecules on reformed poly(methyl methacrylate) via ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Jeong, Hae-Chang; Park, Hong-Gyu; Lee, Ju Hwan; Jang, Sang Bok; Oh, Byeong-Yun; Han, Jeong-Min; Seo, Dae-Shik

    2016-04-01

    We demonstrated uniform LC alignment using IB-irradiated poly(methyl methacrylate) (PMMA) as an alignment layer. We confirmed the topographical changes on PMMA caused by IB irradiation. Moreover, the wettability and chemical modification of the PMMA surface were investigated as functions of incidence angle. The results show that PMMA irradiated with IB at an incidence angle of 30° had a higher molecular polarity than PMMA irradiated with IB at other incidence angles, resulting in strong van der Waals interactions between the surface and LC molecules. The LC cells containing PMMA irradiated with IB at an incidence angle of 30° exhibited good thermal stability (180°) compared with LC cells containing conventional rubbing PI (150°). In addition, LC molecules on PMMA irradiated with IB at an incidence angle of 30° were observed to switch faster than those on conventional rubbing PI. Therefore, PMMA irradiated with IB under the optimal conditions may allow for PMMA to be applied in advanced LC devices as an alternative alignment layer.

  17. Influence of formulation technique on acrylate methacrylate copolymer modified paracetamol matrix tablets.

    PubMed

    Cash-Torunarigha, Omonyemen Edoise; Eichie, Florence Egbomonjiade; Arhewoh, Matthew Ikhuoria

    2015-03-01

    This work was designed to evaluate the influence of various methods such as dry granulation (DG), wet granulation (using the polymer in an ethanolic solution (WGO) or aqueous dispersion (WGA) and solid dispersion (SD) techniques, on properties of paracetamol matrix tablets prepared using varying concentrations of acrylate methacrylate copolymer. Tablet properties were investigated using official and unofficial standards. Drug dissolution profile assessed at pH 1.2 was studied spectrophotometrically at λ(max) of 245 nm. With the use of various kinetic models, the release mechanism of the drug was analyzed. The parameters, maximum amount of drug release (m(∞)) at time t(∞) were obtained, m(∞) was ≥ 91.36 %, while t(∞) was ≥ 4.5 h. The release rate constant (k) for DG tablets was 15.61 h(sup>-1(/sup>, while, WGO, WGA and SD tablets were 12.90, 11.03 and 10.75 h(-1) respectively. The matrix tablets, which exhibited marked retardation in drug release displayed a Higuchi square root of time model (R(2) > 0.98). The mechanism through which the drug was released was governed by Fickian diffusion release (n values < 0.5). The performance of the drug was affected by the formulation technique in the order of SD > WGO > WGA > DG. PMID:25730787

  18. Water sorption and solubility of glass fiber-reinforced denture polymethyl methacrylate resin.

    PubMed

    Miettinen, V M; Vallittu, P K; Docent, D T

    1997-05-01

    Polymethyl methacrylate (PMMA) absorbs water slowly over a period of time, primarily because of the polar properties of the resin molecules. The aim of this study was to determine the water sorption and solubility of heat-cured and chemical-cured glass fiber (GF) PMMA composite used in dentures. The test specimens (n = 5) were fabricated from experimental, unidirectional, continuous GF reinforcement; the GF concentration of the test specimens was approximately 11% by weight. Water sorption and solubility were tested in accordance with International Standards Organization specification No. 1567. The results revealed that the type of acrylate had more of an effect on water sorption than did the presence of GF reinforcement in the test specimen (p = 0.001 and p = 0.049, respectively). In the GF-reinforced test specimens the type of PMMA also affected the water sorption values (p = 0.006). GF reinforcement affected the solubility values of the test specimen (p = 0.002), but the type of acrylate had no effect on solubility (p = 0.585). The results of this study suggest that the water sorption and solubility of unreinforced PMMA and PMMA reinforced with GF are in accordance with International Standards Organization specification No. 1567.

  19. Fabrication and characterization of carbon nanotube reinforced poly(methyl methacrylate) nanocomposites.

    PubMed

    Yu, Suzhu; Juay, Yang Kang; Young, Ming Shyan

    2008-04-01

    Multiwall carbon nanotube (CNT) reinforced poly(methyl methacrylate) (PMMA) nanocomposites have been successfully fabricated with melt blending. Two melt blending approaches of batch mixing and continuous extrusion have been used and the properties of the derived nanocomposites have been compared. The interaction of PMMA and CNTs, which is crucial to greatly improve the polymer properties, has been physically enhanced by adding a third party of poly(vinylidene fluoride) (PVDF) compatibilizer. It is found that the electrical threshold for both PMMA/CNT and PMMA/PVDF/CNT nanocomposites lies between 0.5 to 1 wt% of CNTs. The thermal and mechanical properties of the nanocomposites increase with CNTs and they are further increased by the addition of PVDF For 5 wt% CNT reinforced PMMA/PVDF/CNT nanocomposite, the onset of decomposition temperature is about 17 degrees C higher and elastic modulus is about 19.5% higher than those of neat PMMA. Rheological study also shows that the CNTs incorporated in the PMMA/PVDF/CNT nanocomposites act as physical cross-linkers.

  20. A novel antibacterial orthodontic cement containing a quaternary ammonium monomer dimethylaminododecyl methacrylate

    PubMed Central

    Melo, Mary A.S.; Wu, Junling; Weir, Michael D.; Xu, Hockin H. K.

    2015-01-01

    Demineralized lesions in tooth enamel around orthodontic brackets are caused by acids from cariogenic biofilm. This study aimed to develop a novel antibacterial orthodontic cement by incorporating a quaternary ammonium monomer dimethylaminododecyl methacrylate (DMADDM) into a commercial orthodontic cement, and to investigate the effects on microcosm biofilm response and enamel bond strength. DMADDM, a recently-synthetized antibacterial monomer, was incorporated into orthodontic cement at 0%, 1.5%, 3% and 5% mass fractions. Bond strength of brackets to enamel was measured. A microcosm biofilm model was used to measure metabolic activity, lactic acid production, and colony-forming units (CFU) on orthodontic cements. Shear bond strength was not reduced at 3% DAMDDM (p > 0.1), but was slightly reduced at 5% DMADDM, compared to 0% DMADDM. Biofilm viability was substantially inhibited when in contact with orthodontic cement containing 3% DMADDM. Biofilm metabolic activity, lactic acid production, and CFU were much lower on orthodontic cement containing DMADDM than control cement (p < 0.05). Therefore, the novel antibacterial orthodontic cement containing 3% DMADDM inhibited oral biofilms without compromising the enamel bond strength, and is promising to reduce or eliminate demineralization in enamel around orthodontic brackets. PMID:25035230

  1. Adsorption and electron-induced polymerization of methyl methacrylate on Ru(1010).

    PubMed

    Hedhili, M N; Yakshinskiy, B V; Wasielewski, R; Ciszewski, A; Madey, T E

    2008-05-01

    The adsorption and electron irradiation of methyl methacrylate (MMA) on a Ru(1010) surface have been studied using x-ray photoelectron spectroscopy (XPS), temperature programmed desorption (TPD), and low energy ion scattering. TPD analysis indicates that a monolayer of MMA chemisorbs and dissociates on the Ru(1010) surface. The reaction products observed upon heating include H(2), CO, CO(2), and a small amount of MMA. Physisorbed multilayers of MMA desorb at temperatures around 170 K. Electron irradiation of physisorbed MMA at 140 K leads to a modification of the MMA film: The XPS spectra show an increase in thermal stability of the film with retention of the MMA structure, and indicate that electron irradiation induces polymerization. An increase in the electron bombardment fluence induces a degradation of the formed polymerized species and leads to the accumulation of carbon on the Ru surface. These results are relevant to the accumulation of carbon on surfaces of Ru films that serve as capping layers on MoSi multilayer mirrors used in extreme ultraviolet lithography.

  2. MMP-mediated mesenchymal morphogenesis of pluripotent stem cell aggregates stimulated by gelatin methacrylate microparticle incorporation.

    PubMed

    Nguyen, Anh H; Wang, Yun; White, Douglas E; Platt, Manu O; McDevitt, Todd C

    2016-01-01

    Matrix metalloproteinases (MMPs) remodel the extracellular matrix (ECM) to facilitate epithelial-to-mesenchymal transitions (EMTs) and promote cell specification during embryonic development. In this study, we hypothesized that introducing degradable ECM-based biomaterials to pluripotent stem cell (PSC) aggregates would modulate endogenous proteolytic activity and consequently enhance the differentiation and morphogenesis within 3D PSC aggregates. Gelatin methacrylate (GMA) microparticles (MPs) of low (∼20%) or high (∼90%) cross-linking densities were incorporated into mouse embryonic stem cell (ESC) aggregates, and the effects on MMP activity and cell differentiation were examined with or without MMP inhibition. ESC aggregates containing GMA MPs expressed significantly higher levels of total MMP and MMP-2 than aggregates without MPs. GMA MP incorporation increased expression of EMT markers and enhanced mesenchymal morphogenesis of PSC aggregates. MMP inhibition completely abrogated these effects, and GMA MP-induced MMP activation within ESC aggregates was partially reduced by pSMAD 1/5/8 inhibition. These results suggest that GMA particles activate MMPs by protease-substrate interactions to promote EMT and mesenchymal morphogenesis of ESC aggregates in an MMP-dependent manner. We speculate that controlling protease activity via the introduction of ECM-based materials may offer a novel route to engineer the ECM microenvironment to modulate stem cell differentiation.

  3. Fabrication of poly(methyl methacrylate)-MoS2/graphene heterostructure for memory device application

    NASA Astrophysics Data System (ADS)

    Shinde, Sachin M.; Kalita, Golap; Tanemura, Masaki

    2014-12-01

    Combination of two dimensional graphene and semi-conducting molybdenum disulfide (MoS2) is of great interest for various electronic device applications. Here, we demonstrate fabrication of a hybridized structure with the chemical vapor deposited graphene and MoS2 crystals to configure a memory device. Elongated hexagonal and rhombus shaped MoS2 crystals are synthesized by sulfurization of thermally evaporated molybdenum oxide (MoO3) thin film. Scanning transmission electron microscope studies reveal atomic level structure of the synthesized high quality MoS2 crystals. In the prospect of a memory device fabrication, poly(methyl methacrylate) (PMMA) is used as an insulating dielectric material as well as a supporting layer to transfer the MoS2 crystals. In the fabricated device, PMMA-MoS2 and graphene layers act as the functional and electrode materials, respectively. Distinctive bistable electrical switching and nonvolatile rewritable memory effect is observed in the fabricated PMMA-MoS2/graphene heterostructure. The developed material system and demonstrated memory device fabrication can be significant for next generation data storage applications.

  4. Composite Polylactic-Methacrylic Acid Copolymer Nanoparticles for the Delivery of Methotrexate

    PubMed Central

    Sibeko, Bongani; Choonara, Yahya E.; du Toit, Lisa C.; Modi, Girish; Naidoo, Dinesh; Khan, Riaz A.; Kumar, Pradeep; Ndesendo, Valence M. K.; Iyuke, Sunny E.; Pillay, Viness

    2012-01-01

    The purpose of this study was to develop poly(lactic acid)-methacrylic acid copolymeric nanoparticles with the potential to serve as nanocarrier systems for methotrexate (MTX) used in the chemotherapy of primary central nervous system lymphoma (PCNSL). Nanoparticles were prepared by a double emulsion solvent evaporation technique employing a 3-Factor Box-Behnken experimental design strategy. Analysis of particle size, absolute zeta potential, polydispersity (Pdl), morphology, drug-loading capacity (DLC), structural transitions through FTIR spectroscopy, and drug release kinetics was undertaken. Molecular modelling elucidated the mechanisms of the experimental findings. Nanoparticles with particle sizes ranging from 211.0 to 378.3 nm and a recovery range of 36.8–86.2 mg (Pdl ≤ 0.5) were synthesized. DLC values were initially low (12 ± 0.5%) but were finally optimized to 98 ± 0.3%. FTIR studies elucidated the comixing of MTX within the nanoparticles. An initial burst release (50% of MTX released in 24 hours) was obtained which was followed by a prolonged release phase of MTX over 84 hours. SEM images revealed near-spherical nanoparticles, while TEM micrographs revealed the presence of MTX within the nanoparticles. Stable nanoparticles were formed as corroborated by the chemometric modelling studies undertaken. PMID:22919501

  5. Effect of swift heavy ion irradiation on copper/polymethyl methacrylate nanocomposites

    NASA Astrophysics Data System (ADS)

    Gavade, Chaitali; Kishore, Sangeeta; Singh, N. L.; Khanna, P. K.

    2013-08-01

    In this study, composite films were prepared by incorporating the copper nanoparticles in the insulating polymethyl methacrylate (PMMA) polymer matrix by the solution casting method. These films were irradiated with 120 MeV Si10+ ions at a fluence of 1×1012 ions/cm2. The radiation-induced changes in dielectric, structural and thermal properties of PMMA/Cu nanocomposites were studied using the impedance/gain phase-analyzer, X-ray diffraction (XRD), Fourier transform infra red (FTIR) spectroscopy and differential scanning calorimeter (DSC) techniques. The dielectric properties were observed to enhance with increase in metal nanoparticles' concentration as well as with irradiation fluence. This may be due to the metal/polymer bonding and conversion of the polymeric structure into the hydrogen-depleted carbon network. Crystallite size and crystallinity of pristine and irradiated samples are observed to increase after irradiation as revealed from the XRD analysis. High-energy ion beam irradiation of the semicrystalline polymer nanocomposite changes its T g behavior as observed from the DSC analysis which is corroborated with XRD results. This might be attributed to the rupture of some polymeric bonds, which is also corroborated with the FTIR spectroscopic analysis.

  6. Nanopillar formation from two-shot femtosecond laser ablation of poly-methyl methacrylate

    NASA Astrophysics Data System (ADS)

    Baset, F.; Popov, K.; Villafranca, A.; Alshehri, A. M.; Guay, J.-M.; Ramunno, L.; Bhardwaj, V. R.

    2015-12-01

    We present experimental and numerical studies on the morphological evolution and dynamics of femtosecond laser ablation of bulk poly-methyl methacrylate (PMMA) irradiated with a pair of pulses. We show that a nanopillar-like structure is formed in the middle of the ablation crater for pulse energies below single-shot ablation threshold. The nanopillar is ∼400 nm long, lies adjacent to a nanopore, and protrudes ∼150 nm above the sample surface. As the pulse energy is increased gradually, the nanopillar disappears and the nanopore inside the ablation crater becomes larger. At higher pulse energies, a volcanic eruption like structure appears in the middle of the crater whose size and height increases with energy. 2D molecular dynamics simulations reveal that a nanojet and other features observed at higher pulse energies can be formed when the reflection of a shockwave, induced by the second laser pulse, causes density pinching in the middle of the interaction region that rapidly pushes out molten material towards the surface. The shockwave is reflected from the cold boundaries of a modified region created by the first laser pulse.

  7. Antibacterial effect of dental adhesive containing dimethylaminododecyl methacrylate on the development of Streptococcus mutans biofilm.

    PubMed

    Wang, Suping; Zhang, Keke; Zhou, Xuedong; Xu, Ning; Xu, Hockin H K; Weir, Michael D; Ge, Yang; Wang, Shida; Li, Mingyun; Li, Yuqing; Xu, Xin; Cheng, Lei

    2014-07-18

    Antibacterial bonding agents and composites containing dimethylaminododecyl methacrylate (DMADDM) have been recently developed. The objectives of this study were to investigate the antibacterial effect of novel adhesives containing different mass fractions of DMADDM on Streptococcus mutans (S. mutans) biofilm at different developmental stages. Different mass fractions of DMADDM were incorporated into adhesives and S. mutans biofilm at different developmetal stages were analyzed by MTT assays, lactic acid measurement, confocal laser scanning microscopy and scanning electron microscopy observations. Exopolysaccharides (EPS) staining was used to analyze the inhibitory effect of DMADDM on the biofilm extracellular matrix. Dentin microtensile strengths were also measured. Cured adhesives containing DMADDM could greatly reduce metabolic activity and lactic acid production during the development of S. mutans biofilms (p < 0.05). In earlier stages of biofilm development, there were no significant differences of inhibitory effects between the 2.5% DMADDM and 5% DMADDM group. However, after 72 h, the anti-biofilm effects of adhesives containing 5% DMADDM were significantly stronger than any other group. Incorporation of DMADDM into adhesive did not adversely affect dentin bond strength. In conclusion, adhesives containing DMADDM inhibited the growth, lactic acid production and EPS metabolism of S. mutans biofilm at different stages, with no adverse effect on its dentin adhesive bond strength. The bonding agents have the potential to control dental biofilms and combat tooth decay, and DMADDM is promising for use in a wide range of dental adhesive systems and restoratives.

  8. Use of directly molded poly(methyl methacrylate) channels for microfluidic applications.

    PubMed

    Lee, Sung Hoon; Kang, Do Hyun; Kim, Hong Nam; Suh, Kahp Y

    2010-12-01

    A direct molding method for creating a homogeneous, polymer microfluidic channel is presented. By utilizing capillary rise and subsequent absorption of poly(methyl methacrylate) (PMMA) solution into a solvent-permeable poly(dimethyl siloxane) (PDMS) mold, various circular or elliptic polymer microchannels were fabricated without channel bonding and additional surface modification processes. In addition, the channel diameter was tunable from several micrometres to several hundreds of micrometres by controlling concentration and initial amount of polymer solution for a given PDMS mold geometry. The molded PMMA channels were used for two applications: blocking absorption of Rhodamine B dye and constructing artificial endothelial cell-cultured capillaries. It was observed that the molded PMMA channels effectively prevented absorption and diffusion of Rhodamine molecules over 5 h time span, demonstrating approximately 40 times higher blocking efficiency as compared to porous PDMS channels. Also, calf pulmonary artery endothelial cells (CPAEs) adhered, spread, and proliferated uniformly within the molded microchannels to form near confluency within 3 days and remained viable at day 6 without notable cell death, suggesting high biocompatibility and possibility for emulating in vivo-like three-dimensional architecture of blood vessels. PMID:20938498

  9. A study of normoxic polymer gel using monomer 2-hydroxyethyl methacrylate (HEMA)

    NASA Astrophysics Data System (ADS)

    Ishak, Siti Atiqah; Mustafa, Iskandar Shahrim; Rahman, Azhar Abdul; Moktar, Mohd; Min, Ung Ngie

    2015-04-01

    The aim of this study is to determine the sensitivity of HEMA-polymer gel mixture consist of monomer 2-hydroxyethyl methacrylate (HEMA) with different types of composition. Several composition of HEMA-polymer gel were fabricated and the gels were irradiated with radiation dose between 10 cGy to 100cGy by using x-ray machine and 100 cGy to 1400 cGy by using 6 MV photon beam energy of linear accelerator. The degree of polymerization was evaluated by using magnetic resonance imaging (MRI) with dependence of R2-dose response. Polymer gel consists of cross-linker, anti-oxidant Tetrakis(Hydroxymethyl)phosphonium chloride solution (THPC) and oxygen scavenger hydroquinone shows a stable sensitivity with highest dose dependency. Besides, the results shows the stage polymerization consist of induction, propagation, termination, and chain transfer were dependence with type of chemical mixture and radiation dose. Thus, normoxic HEMA-polymer gel with the different gel formulations can have a better dose resolution and an appropriate recipe must be selected to increase of the sensitivity required and the stability of the dosimeter.

  10. Direct-write bioprinting of cell-laden methacrylated gelatin hydrogels.

    PubMed

    Bertassoni, Luiz E; Cardoso, Juliana C; Manoharan, Vijayan; Cristino, Ana L; Bhise, Nupura S; Araujo, Wesleyan A; Zorlutuna, Pinar; Vrana, Nihal E; Ghaemmaghami, Amir M; Dokmeci, Mehmet R; Khademhosseini, Ali

    2014-06-01

    Fabrication of three dimensional (3D) organoids with controlled microarchitectures has been shown to enhance tissue functionality. Bioprinting can be used to precisely position cells and cell-laden materials to generate controlled tissue architecture. Therefore, it represents an exciting alternative for organ fabrication. Despite the rapid progress in the field, the development of printing processes that can be used to fabricate macroscale tissue constructs from ECM-derived hydrogels has remained a challenge. Here we report a strategy for bioprinting of photolabile cell-laden methacrylated gelatin (GelMA) hydrogels. We bioprinted cell-laden GelMA at concentrations ranging from 7 to 15% with varying cell densities and found a direct correlation between printability and the hydrogel mechanical properties. Furthermore, encapsulated HepG2 cells preserved cell viability for at least eight days following the bioprinting process. In summary, this work presents a strategy for direct-write bioprinting of a cell-laden photolabile ECM-derived hydrogel, which may find widespread application for tissue engineering, organ printing and the development of 3D drug discovery platforms.

  11. Microstructure determination of 2-hydroxy ethyl methacrylate and methyl acrylate copolymers by NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Brar, A. S.; Hooda, Sunita; Goyal, Ashok Kumar

    2007-02-01

    Copolymers of 2-Hydroxy ethyl methacrylate and methyl acrylate (H/M) of different compositions were synthesized by free radical bulk polymerization using azobisisobutyronitrile (AIBN) as an initiator under nitrogen atmosphere. The copolymers compositions were calculated from 1H NMR spectra. The reactivity ratios for H/M copolymers obtained from a linear Kelen-Tudos method (KT) and nonlinear error-in-variables method (EVM) are rH = 3.31 ± 0.08, rM = 0.23 ± 0.00 and rH = 3.32, rM = 0.23, respectively. The complete spectral assignment of methine, methylene, methyl and carbonyl carbon regions in terms of compositional and configurational sequences of H/M copolymers was done with the help of 13C{ 1H} NMR, distortionless enhancement by polarization transfer (DEPT), two-dimensional heteronuclear single quantum coherence (HSQC) along with total correlated spectroscopy (TOCSY). Further, the assignments of carbonyl region were made with the help of heteronuclear multiple bond coherence (HMBC) spectrum.

  12. Microscopy of thin polymer blend films of polystyrene and poly-n-butyl-methacrylate

    NASA Astrophysics Data System (ADS)

    Schmitt, T.; Guttmann, P.; Schmidt, O.; Müller-Buschbaum, P.; Stamm, M.; Schönhense, G.; Schmahl, G.

    2000-05-01

    The structure of thin polymer blend films of polystyrene (PS) and poly-n-butyl-methacrylate (PnBMA) was examined with Transmission X-ray Microscopy (TXM), Scanning Force Microscopy (SFM), X-Ray Photoemission Electron Microscopy (X-PEEM) and Optical Microscopy (OM). Thin films were prepared by spin casting of a toluene solution of the polymer mixture onto silicon wafers retaining the native oxide. Depending on blend composition and annealing conditions smooth films with and without holes or films with well pronounced surface features (ribbons or islands) were produced. By TXM measurements a high lateral resolution study of the as cast and the annealed polymer blend samples was performed. The contrast in TXM is due to different absorption of x-radiation of the used polymers and due to variation in thickness. With X-PEEM the lateral distribution of the two polymers near the surface was mapped by employing the characteristic Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of the polymers. The TXM technique is a microscopic method integrating over the total film thickness, whereas the X-PEEM technique is a highly surface sensitive method. TXM and X-PEEM are therefore complementary methods which provide important information on the structure of thin polymer blend films additional to the standard techniques SFM and OM.

  13. Metal chelate affinity precipitation: purification of BSA using poly(N-vinylcaprolactam-co-methacrylic acid) copolymers.

    PubMed

    Ling, Yuan-Qing; Nie, Hua-Li; Brandford-White, Christopher; Williams, Gareth R; Zhu, Li-Min

    2012-06-01

    This investigation involves the metal chelate affinity precipitation of bovine serum albumin (BSA) using a copper ion loaded thermo-sensitive copolymer. The copolymer of N-vinylcaprolactam with methacrylic acid PNVCL-co-MAA was synthesized by free radical polymerization in aqueous solution, and Cu(II) ions were attached to provide affinity properties for BSA. A maximum loading of 48.1mg Cu(2+) per gram of polymer was attained. The influence of pH, temperature, BSA and NaCl concentrations on BSA precipitation and of pH, ethylenediaminetetraacetic acid (EDTA) and NaCl concentrations on elution were systematically probed. The optimum conditions for BSA precipitation occurred when pH, temperature and BSA concentration were 6.0, 10°C and 1.0 mg/ml, respectively and the most favorable elution conditions were at pH 4.0, with 0.2M NaCl and 0.06 M EDTA. The maximum amounts of BSA precipitation and elution were 37.5 and 33.7 mg BSA/g polymer, respectively. It proved possible to perform multiple precipitation/elution cycles with a minimal loss of polymer efficacy. The results show that PNVCL-co-MAA is a suitable matrix for the purification of target proteins from unfractionated materials.

  14. A study of normoxic polymer gel using monomer 2-hydroxyethyl methacrylate (HEMA)

    SciTech Connect

    Ishak, Siti Atiqah; Mustafa, Iskandar Shahrim; Rahman, Azhar Abdul; Moktar, Mohd; Min, Ung Ngie

    2015-04-24

    The aim of this study is to determine the sensitivity of HEMA-polymer gel mixture consist of monomer 2-hydroxyethyl methacrylate (HEMA) with different types of composition. Several composition of HEMA-polymer gel were fabricated and the gels were irradiated with radiation dose between 10 cGy to 100cGy by using x-ray machine and 100 cGy to 1400 cGy by using 6 MV photon beam energy of linear accelerator. The degree of polymerization was evaluated by using magnetic resonance imaging (MRI) with dependence of R2-dose response. Polymer gel consists of cross-linker, anti-oxidant Tetrakis(Hydroxymethyl)phosphonium chloride solution (THPC) and oxygen scavenger hydroquinone shows a stable sensitivity with highest dose dependency. Besides, the results shows the stage polymerization consist of induction, propagation, termination, and chain transfer were dependence with type of chemical mixture and radiation dose. Thus, normoxic HEMA-polymer gel with the different gel formulations can have a better dose resolution and an appropriate recipe must be selected to increase of the sensitivity required and the stability of the dosimeter.

  15. Development of a methacrylate-terminated PLGA copolymer for potential use in craniomaxillofacial fracture plates.

    PubMed

    Upson, Sarah J; Partridge, Simon W; Tcacencu, Ion; Fulton, David A; Corbett, Ian; German, Matthew J; Dalgarno, Kenneth W

    2016-12-01

    We synthesised methacrylate-terminated PLGA (HT-PLGA, 85:15 LA:GA, 169kDa), for potential use as an adhesively attached craniomaxillofacial fracture fixation plate. The in vitro degradation of molecular weight, pH and flexural modulus were measured over 6weeks storage in PBS at 37°C, with commercially available high (225kDa, H-PLGA) and low (116kDa, L-PLGA) molecular weight 85:15 PLGAs used as comparators. Molecular weights of the materials reduced over 6weeks, HT-PLGA by 48%, H-PLGA by 23% and L-PLGA by 81%. HT-PLGA and H-PLGA exhibited a near constant pH (7.35) and had average flexural moduli in excess of 6GPa when produced, similar to that of the mandible. After 1week storage both exhibited a significant reduction in average modulus, however, from weeks 1-6 no further significant changes were observed, the average modulus never dropped significantly below 5.5GPa. In contrast, the L-PLGA caused a pH drop to below 7.3 by week 6 and an average modulus drop to 0.6 from an initial 4.6GPa. Cell culture using rat bone marrow stromal cells, revealed all materials were cytocompatible and exhibited no osteogenic potential. We conclude that our functionalised PLGA retains mechanical properties which are suitable for use in craniofacial fixation plates. PMID:27612737

  16. Characterisation of poly(methyl methacrylate) film deposited on iron powder particles by electropolymerization

    NASA Astrophysics Data System (ADS)

    Oriňák, Andrej; Oriňáková, Renáta; Heile, Andreas; Talian, Ivan; Terhorst, Markus; Arlinghaus, Heinrich F.

    2007-09-01

    Iron powder microparticles were coated with a poly(methyl methacrylate) (PMMA) film by electropolymerization in a fluidised bed reactor. The formation of a PMMA coating on the microparticles' surface was studied with pyrolysis gas chromatography (Py-GC) fingerprinting as well as time-of-flight secondary ion mass spectrometry (TOF-SIMS). While Py-GC can provide information about PMMA bulk formation and quick information about PMMA deposition on iron microparticles, TOF-SIMS can give detailed information about particle surface PMMA coatings. A TOF-SIMS study was performed in both, positive and negative ion modes with Bi + and Bi3+ primary ions. Static TOF-SIMS macroscans of powder microparticle surface resulted in the identification of the regions with species related to the PMMA fragments in the negative ion region (Bi3+). TOF-SIMS results confirmed that PMMA coating on the iron powder microparticle surface formed an incoherent and inhomogeneous film. PMMA coating was somewhere very thin to supply a sufficient positive charged secondary ion signal. Plating of metallic powder particles by polymeric coating enables the modification of surface and structural properties of materials used in powder metallurgy. PMMA coated iron powder microparticles can be innovative as lubricants in such a way that, when they are subjected to pressure, they burst and release carbon to metal powder. The main aim of this research work is to characterise PMMA coatings deposited by electropolymerization on the surface of iron powder microparticles.

  17. Raman spectroscopy of 2-hydroxyethyl methacrylate-acrylamide copolymer using gamma irradiation for crosslinking

    SciTech Connect

    Goheen, Steven C.; Saunders, Rachel M.; Davis, Rachel M.; Harvey, Scott D.; Olsen, Peter C.

    2006-02-18

    A copolymer hydrogel was made by mixing acrylamide and 2-hydroxyethyl methacrylate monomers in water and polymerizing with gamma irradiation. The progress of polymerization and the vibrational structure of the hydrogel was examined using Raman spectroscopy. Raman spectra indicated that the co-polymer has a molecular structure different from polyacrylamide or the individual monomers. The Raman data also indicate the presence of crosslinking at the C=O, NH2 and OH side chains. The spectra further suggest the continuous lengthening of the backbone of the polymers with increasing gamma dose. This is shown as the increase in C-C modes as C=C vibrations decrease. Raman spectra changed most dramatically as the monomer mixture became a gel at a dose of approximately 320 Gy. Spectral differences were subtler with doses exceeding 640 Gy, although chain lengthening continued beyond 1500 Gy. Potential applications of the copolymer hydrogel include reconstructive tissue as well as a standard material for radiation protection dosimetry. Results are discussed in relation to other potential applications of this polymer and dose-dependent changes in the Raman spectrum.

  18. Coil-globule transition of poly(methyl methacrylate) in isoamyl acetate

    NASA Astrophysics Data System (ADS)

    Nakata, Mitsuo; Nakagawa, Tomohide

    1997-09-01

    The coil-globule transition was studied by static light scattering measurements on poly(methyl methacrylate) with the molecular weight Mw×10-6=2.35 and 4.4 in isoamyl acetate. Since the phase separation of the dilute solution occurred very slowly, the measurements could be made in the broad temperature range from near the Θ temperature 61 °C to 0 °C 30 min after a quench of the solution. The observed expansion factor α2 for the radius of gyration was represented as a function only of τM1/2 and showed a constant value at large -τM1/2 with τ being 1-Θ/T. A quantitative comparison between a recent theory for a contracted coil and the data of α2 revealed the coil-globule crossover phenomena. The behavior of plot of 1/α3 versus -τM1/2 was distinctly different in the three ranges, i.e., coil range, globule range, and range of a constant α. The plot of the observed second virial coefficient A2 against temperature yielded a minimum as predicted from a theory of A2 below the Θ temperature.

  19. Coil-globule transition of poly(methyl methacrylate) in isoamyl acetate

    SciTech Connect

    Nakata, M.; Nakagawa, T.

    1997-09-01

    The coil-globule transition was studied by static light scattering measurements on poly(methyl methacrylate) with the molecular weight M{sub w}{times}10{sup {minus}6}=2.35 and 4.4 in isoamyl acetate. Since the phase separation of the dilute solution occurred very slowly, the measurements could be made in the broad temperature range from near the {Theta} temperature 61{degree}C to 0{degree}C 30 min after a quench of the solution. The observed expansion factor {alpha}{sup 2} for the radius of gyration was represented as a function only of {tau}M{sup 1/2} and showed a constant value at large {minus}{tau}M{sup 1/2} with {tau} being 1{minus}{Theta}/T. A quantitative comparison between a recent theory for a contracted coil and the data of {alpha}{sup 2} revealed the coil-globule crossover phenomena. The behavior of plot of 1/{alpha}{sup 3} versus {minus}{tau}M{sup 1/2} was distinctly different in the three ranges, i.e., coil range, globule range, and range of a constant {alpha}. The plot of the observed second virial coefficient A{sub 2} against temperature yielded a minimum as predicted from a theory of A{sub 2} below the {Theta} temperature. {copyright} {ital 1997} {ital The American Physical Society}

  20. Kinetics of chain aggregation of poly(methyl methacrylate) in isoamyl acetate

    NASA Astrophysics Data System (ADS)

    Nakata, Mitsuo; Nakagawa, Tomohide; Nakamura, Yoshiki; Wakatsuki, Syogo

    1999-02-01

    For dilute solutions of poly(methyl methacrylate) in isoamyl acetate with the molecular weight Mw=2.35×106, the phase separation process was observed as an aggregation process of polymer chains by light-scattering measurements. The aggregation process was measured for a period of hours at four polymer concentrations and at about 15 K below the phase separation temperature. The light-scattering data analysis by Guinier plot yielded the average molecular weight w and radius z1/2 for polymer aggregates as a function of time t and revealed the exponential growth of w˜egt and z˜eht. The coefficients g and h were proportional to the polymer concentration. A shape of the observed scattering function was independent of the concentration and time. The fractal dimension for zD/2 was determined to be D=2.86±0.03. These characteristic features of the polymer aggregation were represented by the Smoluchowski equation for cluster-cluster aggregation with the collision kernel (i+j) for imer and jmer. The observed scattering function and fractal dimension were analyzed by the Smoluchowski equation with the assumed value D=3 for monodisperse clusters.

  1. Segmental and local dynamics of stacked thin films of poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Hayashi, Tatsuhiko; Fukao, Koji

    2014-02-01

    The glass transition temperature and the dynamics of the α and β processes have been investigated using differential scanning calorimetry and dielectric relaxation spectroscopy during successive annealing processes above the glass transition temperature for stacked thin films of poly(methyl methacrylate) (PMMA) of various thicknesses. The glass transition temperature and the dynamics of the α process (segmental motion) of as-stacked PMMA thin films exhibit thin-film-like behavior, insofar as the glass transition temperature is depressed and the dynamics of the α process are faster than those of the bulk system. Annealing at high temperature causes the glass transition temperature to increase from the reduced value and causes the dynamics of the α process to become slower approaching those of the bulk. Contrary to the segmental motion, the relaxation time of the β process (local motion) of the stacked PMMA thin films is almost equal to that of the bulk PMMA and is unaffected by the annealing process. However, the relaxation strengths of both the α process and β process show a strong correlation between each other. The sum of the relaxation strengths remains almost unchanged, while the individual relaxation strengths change during the annealing process. The fragility index of the stacked PMMA thin films increases with annealing, which suggests that the glassy state of the stacked thin films changes from strong to fragile.

  2. Photomechanical actuator device based on disperse red 1 doped poly(methyl methacrylate) optical fiber

    NASA Astrophysics Data System (ADS)

    Ye, Xianjun

    The photomechanical effect is the phenomenon involving any mechanical property change of a material induced by light exposure. Photomechanical devices can be built with superior performance over traditional devices and offer versatile control tactics. Previous experiments show that disperse red 1 azobenzene (DR1) doped poly(methyl methacrylate) (PMMA) optical fiber has a fast photomechanical response upon asymmetrical 633nm laser irradiation originating in photoisomerization of the dopants between the cis and trans forms, which causes an elongation of the polymer fiber. In this work, laser light of 355nm wavelength is used to investigate the dynamics of the trans to cis photoisomerization process, which should result in length contraction of the DR1 doped PMMA polymer fiber. A three-point-contact optically-actuated beam controlling tilt mount is made and used as the measurement apparatus to study this process. The photomechanical fiber is observed to elongate upon UV irradiation. Numerical simulations, which take into account the coupled effect between the laser-induced temperature increase and population density change of the dye molecules, show that contraction of the fiber due to direct trans-cis photoisomerization is overwhelmed by elongation due to the photo-thermally-stimulated cis-trans isomerization under high intensity. An ink coated entrance face of the fiber is placed in the measurement tilt mount and is found to exhibit contraction in the fast process under low intensity without sacrificing the good signal to noise ratio enjoyed in the high intensity case.

  3. Dual-Cross-Linked Methacrylated Alginate Sub-Microspheres for Intracellular Chemotherapeutic Delivery.

    PubMed

    Fenn, Spencer L; Miao, Tianxin; Scherrer, Ryan M; Oldinski, Rachael A

    2016-07-20

    Intracellular delivery vehicles comprised of methacrylated alginate (Alg-MA) were developed for the internalization and release of doxorubicin hydrochloride (DOX). Alg-MA was synthesized via an anhydrous reaction, and a mixture of Alg-MA and DOX was formed into sub-microspheres using a water/oil emulsion. Covalently cross-linked sub-microspheres were formed via exposure to green light, in order to investigate effects of cross-linking on drug release and cell internalization, compared to traditional techniques, such as ultraviolet (UV) light irradiation. Cross-linking was performed using light exposure alone or in combination with ionic cross-linking using calcium chloride (CaCl2). Alg-MA sub-microsphere diameters were between 88 and 617 nm, and ζ-potentials were between -20 and -37 mV. Using human lung epithelial carcinoma cells (A549) as a model, cellular internalization was confirmed using flow cytometry; different sub-microsphere formulations varied the efficiency of internalization, with UV-cross-linked sub-microspheres achieving the highest internalization percentages. While blank (nonloaded) Alg-MA submicrospheres were noncytotoxic to A549 cells, DOX-loaded sub-microspheres significantly reduced mitochondrial activity after 5 days of culture. Photo-cross-linked Alg-MA sub-microspheres may be a potential chemotherapeutic delivery system for cancer treatment.

  4. Effect of ZnO on the Thermal Degradation Behavior of Poly(Methyl Methacrylate) Nanocomposites.

    PubMed

    Japić, Dajana; Marinšek, Marjan; Crnjak Orel, Zorica

    2016-01-01

    The influence of ZnO nanoparticles on the thermal degradation behavior of poly(methyl methacrylate) (PMMA) was tested using thermoanalytical techniques. The studied materials were investigated using TG, DTA, EGA, XRD, SEM and TEM. The ZnO nanoparticles were synthesized via precipitation by adding LiOH into Zn2+ water/ethylene glycol solutions. The ZnO-PMMA nanocomposites were prepared by adding the appropriate amount of ZnO into MMA and subsequent MMA radical polymerization. According to the experimental results and model-free isoconversional activation energy calculations, the addition of ZnO into PMMA played a double role. The ZnO concentrations up to 0.15% stabilized the composite by shifting the degradation interval toward higher temperatures and increasing the apparent activation energy relative to pure PMMA. At higher concentrations, the catalytic effect of ZnO started to prevail and was reflected in the lower temperature intervals of intense PMMA degradation and lower apparent activation energy. The addition of ZnO generally did not change the nature of the PMMA decomposition process. PMID:27640380

  5. Oriented growth of rat Schwann cells on aligned electrospun poly(methyl methacrylate) nanofibers.

    PubMed

    Xia, Haijian; Sun, Xiaochuan; Liu, Dan; Zhou, Yudong; Zhong, Dong

    2016-10-15

    Transplanted Schwann cells have the potential to serve as a support for regenerating neurites after spinal cord injury. However, implanted Schwann cells die off rapidly once transplanted partly owing to the absence of a proper matrix support, with a glia scar and a cavity being present instead at the injury site. For this report, we evaluated aligned electrospun poly(methyl methacrylate) nanofibers as a Schwann cell-loading scaffold in vitro. By monitoring the fluorescence of green fluorescence protein-containing Schwann cells cultured on nanofibers, we found that aligned nanofibers provided better support for the cells than did non-aligned nanofibers. The cells elongated along the long axes of the aligned nanofibers and formed longer cell processes than when the substrate was non-aligned nanofibers. By coculturing Schwann cells with dorsal root ganglion neurons, it was also found that Schwann cells and neurites of dorsal root ganglion neurons could share and both elongate along the orientation of aligned nanofibers and thus they had a higher chance of colocalization than cocultured on film and non-aligned fibers, which might be beneficial to the ensuring process of myelination. The results of the study indicate that aligned electrospun nanofibers may serve as a Schwann cell-loading scaffold for future implantation research. PMID:27653871

  6. Nano-imprint lithography using poly (methyl methacrylate) (PMMA) and polystyrene (PS) polymers

    NASA Astrophysics Data System (ADS)

    Ting, Yung-Chiang; Shy, Shyi-Long

    2016-04-01

    Nano-imprinting lithography (NIL) technology, as one of the most promising fabrication technologies, has been demonstrated to be a powerful tool for large-area replication up to wafer-level, with features down to nanometer scale. The cost of resists used for NIL is important for wafer-level large-area replication. This study aims to develop capabilities in patterning larger area structure using thermal NIL. The commercial available Poly (Methyl Methacrylate) (PMMA) and Polystyrene (PS) polymers possess a variety of characteristics desirable for NIL, such as low material cost, low bulkvolumetric shrinkage, high spin coating thickness uniformity, high process stability, and acceptable dry-etch resistance. PMMA materials have been utilized for positive electron beam lithography for many years, offering high resolution capability and wide process latitude. In addition, it is preferable to have a negative resist like PMMA, which is a simple polymer with low cost and practically unlimited shelf life, and can be dissolved easily using commercial available Propylene glycol methyl ether acetate (PGMEA) safer solvent to give the preferred film thickness. PS is such a resist, as it undergoes crosslinking when exposed to deep UV light or an electron beam and can be used for NIL. The result is a cost effective patterning larger area structure using thermal nano-imprint lithography (NIL) by using commercial available PMMA and PS ploymers as NIL resists.

  7. Gas-to-liquid permeation in silicon-containing, crosslinked, glassy copolymers of methyl methacrylate.

    PubMed

    Yang, W M; Peppas, N A

    1983-10-01

    Copolymers of methyl methacrylate with disiloxane derivatives have been proposed as biomaterials for contact lens applications. Although glassy, these copolymers exhibit high oxygen permeability and adequate wettability so that they can be used for manufacture of hard, extended wear lenses. Crosslinked copolymers of poly(methylmethacrylate-co-1,3-bis(methacryloxymethyl) -1,1,3,3-tetramethyl-disiloxane), P(MMA-co-BMTDS), containing from 0.085 to 0.53 mole fraction of BMTDS were prepared and tested for oxygen permeation using a novel apparatus which simulates the atmosphere/lens/cornea conditions. The gas-to-liquid dissolved oxygen permeability, P gd1 was determined and it was found to increase with BMTDS content. Permeability values for P(MMA-co-BMTDS) at 34 degrees C were significantly higher than for pure homopolymer PMMA, although these copolymers were glassy at this temperature. The increased oxygen permeation was attributed to increased oxygen solubility in the copolymers due to the presence of the -Si-O-bonds. PMID:6640054

  8. In-situ synthesis and performance of titanium oxide/poly(methyl methacrylate) nanocomposites.

    PubMed

    Bandugula, Uttam C; Clayton, L M; Harmon, J P; Kumar, Ashok

    2005-05-01

    Polymer nanocomposites have elicited extensive research efforts due to their potential to exhibit spectacular properties. They have immense potential and are befitting materials to serve as an ideal and futuristic alternative for varied applications. Poly(methyl methacrylate) (PMMA) and titanium oxide (TiO2) nanocomposites used in this study were fabricated by an in-situ free radical polymerization process. Three point bend tests were conducted with a modified universal microtribometer to evaluate fracture toughness. The results indicated that the stress intensity values increase as the concentration of titanium oxide increases up to 1 vol% and subsequently decrease at higher concentrations. Scanning electron microscopy (SEM) images of fracture surfaces afforded clues as to the possible deformation mechanism. Ultraviolet-visible spectroscopy (UV-vis) evaluated the degree of transparency of the nanocomposites. It was observed that samples became opaque as the concentration was increased beyond 0.01% volume fraction. X-ray diffraction characterized the TiO2 crystalline phase and Scherrer's equation was used to calculate the crystallite size. Among the concentrations considered the 3% volume fraction sample had the largest crystallite size. Finally, microhardness measurements further characterized the mechanical properties of the composites.

  9. VA-086 methacrylate gelatine photopolymerizable hydrogels: A parametric study for highly biocompatible 3D cell embedding.

    PubMed

    Occhetta, Paola; Visone, Roberta; Russo, Laura; Cipolla, Laura; Moretti, Matteo; Rasponi, Marco

    2015-06-01

    The ability to replicate in vitro the native extracellular matrix (ECM) features and to control the three-dimensional (3D) cell organization plays a fundamental role in obtaining functional engineered bioconstructs. In tissue engineering (TE) applications, hydrogels have been successfully implied as biomatrices for 3D cell embedding, exhibiting high similarities to the natural ECM and holding easily tunable mechanical properties. In the present study, we characterized a promising photocrosslinking process to generate cell-laden methacrylate gelatin (GelMA) hydrogels in the presence of VA-086 photoinitiator using a ultraviolet LED source. We investigated the influence of prepolymer concentration and light irradiance on mechanical and biomimetic properties of resulting hydrogels. In details, the increasing of gelatin concentration resulted in enhanced rheological properties and shorter polymerization time. We then defined and validated a reliable photopolymerization protocol for cell embedding (1.5% VA-086, LED 2 mW/cm2) within GelMA hydrogels, which demonstrated to support bone marrow stromal cells viability when cultured up to 7 days. Moreover, we showed how different mechanical properties, derived from different crosslinking parameters, strongly influence cell behavior. In conclusion, this protocol can be considered a versatile tool to obtain biocompatible cell-laden hydrogels with properties easily adaptable for different TE applications.

  10. Olfactory function in chemical workers exposed to acrylate and methacrylate vapors

    SciTech Connect

    Schwartz, B.S.; Doty, R.L.; Frye, R. ); Monroe, C.; Barker, S. )

    1989-05-01

    An investigation of the olfactory function of 731 workers at a chemical facility which manufactures acrylates and methacrylates was undertaken using a standardized quantitative test. In a cross-section analysis of the data, no associations of chemical exposure with olfactory test scores were observed. A nested case-control study designed to evaluate the cumulative effects of exposure on olfactory function, however, revealed elevated crude exposure odds ratios of 2.0 (1.1, 3.8) for all workers and 6.0 (1.7, 21.5) for workers who never smoked cigarettes. Logistic regression analysis, adjusting for multiple confounders, revealed exposure odds ratios of 2.8 (1.1, 7.0) and 13.5 (2.1, 87.6) in these same groups, respectively, and a dose-response relationship between olfactory dysfunction and cumulative exposure scores - semi-quantitative indices of lifetime exposure to the acrylates. The data also revealed decreasing exposure odds ratios with increasing duration since last exposure to these chemicals, suggesting that the effects may be reversible.

  11. An angled nano-tunnel fabricated on poly(methyl methacrylate) by a focused ion beam

    NASA Astrophysics Data System (ADS)

    Her, Eun Kyu; Chung, Hee-Suk; Moon, Myoung-Woon; Oh, Kyu Hwan

    2009-07-01

    Angled nano-scale tunnels with high aspect ratio were fabricated on poly(methyl methacrylate) (PMMA) using a focused ion beam (FIB). The fabrication parameters such as ion fluence, incidence angle, and acceleration voltage of the Ga+ ion beam were first studied on the PMMA surface to explore the formation of the nano-scale configurations such as nano-holes and cones with diameter in the range of 50-150 nm at an ion beam acceleration voltage of 5-20 kV. It was also found that the PMMA surface exposed to FIB was changed into an amorphous graphitic structure. Angled nano-scale tunnels were fabricated with high aspect ratio of 700-1500 nm in depth and 60 nm in mean diameter at an ion beam acceleration voltage of 5 kV and under a specific ion beam current. The angle of the nano-tunnels was found to follow the incident angle of the ion beam tilted from 0° to 85°, which has the potential for creating a mold for anisotropic adhesives by mimicking the hairs on a gecko's feet.

  12. Influence of Ionic Complexes on Phase Behavior of Polystyrene-b-poly(methyl methacrylate) Copolymers

    SciTech Connect

    Wang,J.; Chen, W.; Roy, C.; Sievert, J.; Russell, T.

    2008-01-01

    The influence of ionic complexes on phase behavior of PS-b-PMMA copolymers over a wide range of molecular weights and PS volume fractions was investigated by small-angle X-ray scattering (SAXS), grazing incidence small-angle X-ray scattering (GISAXS), transmission electron microscopy (TEM), and neutron reflectivity (NR). The disorder-to-order transition (DOT) in both symmetric and asymmetric copolymers indicates that the overall Flory-Huggins segmental interaction parameter, eff, between polystyrene (PS) and poly(methyl methacrylate) (PMMA) blocks with lithium-PMMA complexes is increased compared to that of the neat copolymers. This enhanced eff further results in an order-to-order transition (OOT), from spheres to cylinders, and an increase in the ordering and spacing of microdomains. Moreover, transitional metal ionic complexes, such as copper-PMMA complexes, are found to have the similar influence on phase behavior of PS-b-PMMA copolymers. The formation of ionic complexes in the copolymers not only offers a parameter to tune the degree of microphase separation of PS-b-PMMA copolymers but also provides a way to fabricate multifunctional materials.

  13. Morphological Origin of Thermomechanical Behavior in Semicrystalline Ethylene/Methacrylic Acid Ionomers

    NASA Astrophysics Data System (ADS)

    Wakabayashi, Katsuyuki; Register, Richard A.

    2006-03-01

    Two peculiar and intriguing phenomena in ethylene/methacrylic acid (E/MAA) ionomers are an initial sharp increase in stiffness with neutralization and an inverse dependence of Young’s modulus on crystallinity. We have identified how the polyethylene crystallites, amorphous polymer segments, and ionic aggregates combine to produce these unusual effects. At temperatures just below the melting point of the primary crystallites, the ionomers can be satisfactorily described as two-phase composites of crystallites and ionically-crosslinked rubber, but at room temperature, the modulus is much greater. We trace this effect to a synergy between the ionic aggregates and secondary crystallites, which together form percolated rigid pathways through the amorphous phase at room temperature, generating a far higher modulus than one would anticipate from the modest crystallinity and ion content. When the secondary crystallites melt and/or the segments in the regions of restricted mobility surrounding the aggregates devitrify, these paths break down and the simple two-phase composite description is recovered.

  14. Durability of Poly(Methyl Methacrylate) Lenses Used in Concentrating Photovoltaic Modules: Preprint

    SciTech Connect

    Miller, D. C.; Gedvilas, L. M.; To, B.; Kennedy, C. E.; Kurtz, S. R.

    2010-08-01

    Concentrating photovoltaic (CPV) technology has recently gained interest based on their expected low levelized cost of electricity, high efficiency, and scalability. Many CPV systems use Fresnel lenses made of poly(methyl methacrylate)(PMMA) to obtain a high optical flux density. The optical and mechanical durability of such components, however, are not well established relative to the desired service life of 30 years. Specific reliability issues may include: reduced optical transmittance, discoloration, hazing, surface erosion, embrittlement, crack growth, physical aging, shape setting (warpage), and soiling. The initial results for contemporary lens- and material-specimens aged cumulatively to 6 months are presented. The study here uses an environmental chamber equipped with a xenon-arc lamp to age specimens at least 8x the nominal field rate. A broad range in the affected characteristics (including optical transmittance, yellowness index, mass loss, and contact angle) has been observed to date, depending on the formulation of PMMA used. The most affected specimens are further examined in terms of their visual appearance, surface roughness (examined via atomic force microscopy), and molecular structure (via Fourier transform infrared spectroscopy).

  15. Analysis of stochastic effects in chemically amplified poly(4-hydroxystyrene-co-t-butyl methacrylate) resist

    NASA Astrophysics Data System (ADS)

    Kozawa, Takahiro; Santillan, Julius Joseph; Itani, Toshiro

    2016-07-01

    Understanding of stochastic phenomena is essential to the development of a highly sensitive resist for nanofabrication. In this study, we investigated the stochastic effects in a chemically amplified resist consisting of poly(4-hydroxystyrene-co-t-butyl methacrylate), triphenylsulfonium nonafluorobutanesulfonate (acid generator), and tri-n-octylamine (quencher). Scanning electron microscopy (SEM) images of resist patterns were analyzed by Monte Carlo simulation on the basis of the sensitization and reaction mechanisms of chemically amplified extreme ultraviolet resists. It was estimated that a ±0.82σ fluctuation of the number of protected units per polymer molecule led to line edge roughness formation. Here, σ is the standard deviation of the number of protected units per polymer molecule after postexposure baking (PEB). The threshold for the elimination of stochastic bridge generation was 4.38σ (the difference between the average number of protected units after PEB and the dissolution point). The threshold for the elimination of stochastic pinching was 2.16σ.

  16. The effect of processing conditions on the properties of poly(methyl methacrylate) fibers.

    PubMed

    Wright, Debra D; Lautenschlager, Eugene P; Gilbert, Jeremy L

    2002-01-01

    Brittle failure of bone cement remains a problem for the long-term stability of hip prostheses. Fibers have been developed from poly(methyl methacrylate) (PMMA) that retain the chemistry of bone cement, but improve the mechanical properties greatly. To fabricate the fibers, a polymer melt is extruded out of a small die (spinneret) and pulled onto a take-up wheel. Varying the speed of extrusion and temperature of the melt can control the viscosity of the molten polymer. This study examines the effect of melt viscosity on the resultant properties of fibers fabricated from PMMA. The goals are to optimize fiber processing and determine processing-structure--property relationships. Resultant fibers had moderate to high levels of retained molecular orientation, and ultimate tensile strengths (UTS) ranging from 60 to 225 MPa, moduli from 1.5 to 3.5 GPa, and strain to failure from 10 to 40%. Fibers fabricated at a constant viscosity and draw velocity had identical properties, whereas decreasing the viscosity generally increased the mechanical properties and retained orientation. Linear regression models were constructed to predict how the processing variables affect the structure (orientation) of the fiber and how the structure affects the UTS. This can be used to design efficient processing methods for PMMA fibers.

  17. A Classification System for the Spread of Polymethyl Methacrylate in Vertebral Bodies Treated with Vertebral Augmentation

    PubMed Central

    Frankl, Joseph; Sakata, Michael P.; Choudhary, Gagandeep; Hur, Seung; Peterson, Andrew; Hennemeyer, Charles T.

    2016-01-01

    In this study, we develop a classification system for describing polymethyl methacrylate (PMMA) spread in vertebral bodies after kyphoplasty or vertebroplasty for vertebral compression fractures (VCFs) and for assessing whether PMMA spread varies between operators, VCF etiology, or vertebral level. Intraoperative fluoroscopic images of 198 vertebral levels were reviewed in 137 patients (women, 84; men, 53; mean age, 75.8 ± 12.5; and those with a diagnosis of osteoporosis, 63%) treated with kyphoplasty between January 01, 2015 and May 31, 2015 at a single center to create a 5-class descriptive system. PMMA spread patterns in the same images were then classified by 2 board-certified radiologists, and a third board-certified radiologist resolved conflicts. A total of 2 primary PMMA spread patterns were identified, namely, acinar and globular, with subtypes of localized acinar, diffuse globular, and mixed, to describe an equal combination of patterns. Interrater reliability using the system was moderate (κ = 0.47). After resolving conflicts, the most common spread class was globular (n = 63), followed by mixed (n = 58), diffuse globular (n = 30), acinar (n = 27), and localized acinar (n = 20). The spread class after treatment by the 2 most frequent operators differed significantly (n1 = 63, n2 = 70; P < .0001). There was no difference in the spread class between VCF etiologies or vertebral levels. PMMA spread may, therefore, be a modifiable parameter that affects kyphoplasty and vertebroplasty efficacy and adverse events. PMID:27795998

  18. Bacterial membranes are the target for antimicrobial polysiloxane-methacrylate copolymer.

    PubMed

    Jońca, Joanna; Tukaj, Cecylia; Werel, Władysław; Mizerska, Urszula; Fortuniak, Witold; Chojnowski, Julian

    2016-03-01

    Antibacterial polysiloxane polymers with pending tert-butylamine groups are a novel class of compounds that are compatible with silicone elastomers, but their mechanism of action is not well understood. The research into their action mechanism was conducted on a polysiloxane copolymer grafted with tert-butylaminoethyl methacrylate and covalently attached fluorescein. Fluorometric measurements results suggest that the polymer forms a stable link with bacteria. The results of β-galactosidase enzyme assay with the use of ortho-nitrophenyl-β-galactoside as a substrate show that the polymer has a damaging effect on bacterial membranes. The scanning and transmission electron micrographs of Escherichia coli cells incubated with the polymer prove further that the polymer's site of action is bacterial cell membranes. In order to investigate the polymer interaction with bacterial membranes the fluorescein labelled polymer was incubated with bacterial cells and membranes isolation and identification method was next applied. The E. coli membrane fractions were identified by light scattering, protein content, oxidase NADH activity and N-phenylnaphtylamine fluorescence measurements, as well as electron microscopy. Oxidase NADH and N-phenylnaphtylamine were the inner membrane markers. The bacterial membranes were then tested for the presence of the polymer. The experiments gave evidence that the copolymer binds to the inner bacterial membrane. Further studies, where the copolymer was incubated with isolated mixed (inner and outer) membrane fractions, proved that the copolymer exerts more destructive effect on E. coli outer membrane. The damaging effect on the membranes is concentration dependent.

  19. Development characteristics of polymethyl methacrylate in alcohol/water mixtures: a lithography and Raman spectroscopy study.

    PubMed

    Ocola, Leonidas E; Costales, Maya; Gosztola, David J

    2016-01-22

    Poly methyl methacrylate (PMMA) is the most widely used resist in electron beam lithography. This paper reports on a lithography and Raman spectroscopy study of development characteristics of PMMA in methanol, ethanol and isopropanol mixtures with water as developers. We have found that ethanol/water mixtures at a 4:1 volume ratio are an excellent, high resolution, non-toxic developer for exposed PMMA. We have also found that the proper methodology to use so that contrast data can be compared to techniques used in polymer science is not to rinse the developed resist but to immediately dry with nitrogen. Our results show how powerful simple lithographic techniques can be used to study ternary polymer solvent solutions when compared to other techniques used in the literature. Raman data show that both tightly bonded -OH groups and non-hydrogen bonded -OH groups play a role in the development of PMMA. Tightly hydrogen bonded -OH groups show pure Lorentzian Raman absorption only in the concentration ranges where ethanol/water and IPA/water mixtures are effective developers of PMMA, pointing to possible ordering or reduced amorphization due to the liquid state. The impact of understanding these interactions may open doors to a new developers of other electron beam resists that can reduce the toxicity of the waste stream.

  20. Highly Transparent and Toughened Poly(methyl methacrylate) Nanocomposite Films Containing Networks of Cellulose Nanofibrils.

    PubMed

    Dong, Hong; Sliozberg, Yelena R; Snyder, James F; Steele, Joshua; Chantawansri, Tanya L; Orlicki, Joshua A; Walck, Scott D; Reiner, Richard S; Rudie, Alan W

    2015-11-18

    Cellulose nanofibrils (CNFs) are a class of cellulosic nanomaterials with high aspect ratios that can be extracted from various natural sources. Their highly crystalline structures provide the nanofibrils with excellent mechanical and thermal properties. The main challenges of CNFs in nanocomposite applications are associated with their high hydrophilicity, which makes CNFs incompatible with hydrophobic polymers. In this study, highly transparent and toughened poly(methyl methacrylate) (PMMA) nanocomposite films were prepared using various percentages of CNFs covered with surface carboxylic acid groups (CNF-COOH). The surface groups make the CNFs interfacial interaction with PMMA favorable, which facilitate the homogeneous dispersion of the hydrophilic nanofibrils in the hydrophobic polymer and the formation of a percolated network of nanofibrils. The controlled dispersion results in high transparency of the nanocomposites. Mechanical analysis of the resulting films demonstrated that a low percentage loading of CNF-COOH worked as effective reinforcing agents, yielding more ductile and therefore tougher films than the neat PMMA film. Toughening mechanisms were investigated through coarse-grained simulations, where the results demonstrated that a favorable polymer-nanofibril interface together with percolation of the nanofibrils, both facilitated through hydrogen bonding interactions, contributed to the toughness improvement in these nanocomposites.

  1. Development characteristics of polymethyl methacrylate in alcohol/water mixtures: a lithography and Raman spectroscopy study

    NASA Astrophysics Data System (ADS)

    Ocola, Leonidas E.; Costales, Maya; Gosztola, David J.

    2016-01-01

    Poly methyl methacrylate (PMMA) is the most widely used resist in electron beam lithography. This paper reports on a lithography and Raman spectroscopy study of development characteristics of PMMA in methanol, ethanol and isopropanol mixtures with water as developers. We have found that ethanol/water mixtures at a 4:1 volume ratio are an excellent, high resolution, non-toxic developer for exposed PMMA. We have also found that the proper methodology to use so that contrast data can be compared to techniques used in polymer science is not to rinse the developed resist but to immediately dry with nitrogen. Our results show how powerful simple lithographic techniques can be used to study ternary polymer solvent solutions when compared to other techniques used in the literature. Raman data show that both tightly bonded -OH groups and non-hydrogen bonded -OH groups play a role in the development of PMMA. Tightly hydrogen bonded -OH groups show pure Lorentzian Raman absorption only in the concentration ranges where ethanol/water and IPA/water mixtures are effective developers of PMMA, pointing to possible ordering or reduced amorphization due to the liquid state. The impact of understanding these interactions may open doors to a new developers of other electron beam resists that can reduce the toxicity of the waste stream.

  2. Mineralized gelatin methacrylate-based matrices induce osteogenic differentiation of human induced pluripotent stem cells

    PubMed Central

    Kang, Heemin; Shih, Yu-Ru V.; Hwang, Yongsung; Wen, Cai; Rao, Vikram; Seo, Timothy; Varghese, Shyni

    2014-01-01

    Human induced pluripotent stem cells (hiPSCs) are a promising cell source with pluripotency and self-renewal properties. Design of simple and robust biomaterials with an innate ability to induce lineage-specificity of hiPSCs is desirable to realize their applications in regenerative medicine. In this study, we investigated the potential of biomaterials containing calcium phosphate minerals to induce osteogenic differentiation of hiPSCs. hiPSCs cultured using mineralized gelatin methacrylate-based matrices underwent osteogenic differentiation ex vivo, both in two- dimensional (2-D) and three-dimensional (3-D) cultures, in growth medium devoid of any osteogenic-inducing chemical components or growth factors. Our findings that osteogenic differentiation of hiPSCs can be achieved through biomaterial-based cues alone present new avenues for personalized regenerative medicine. Such biomaterials that could not only act as structural scaffolds, but could also provide tissue-specific functions such as directing stem cell differentiation commitment, have great potential in bone tissue engineering. PMID:25153779

  3. Cell-induced flow-focusing instability in gelatin methacrylate microdroplet generation.

    PubMed

    Jung, Jinmu; Oh, Jonghyun

    2014-05-01

    Photo-crosslinkable gelatin methacrylate (GelMa) microspheres are applicable to deliver cells or drugs in biological or biomedical applications. To fabricate GelMa microdroplets, a flow focusing technique with advantages of size control and rapid production was used in a T-junction microfluidic device. Instability played an important role in promoting microdroplet uniformity. 5 wt. % GelMa prepolymer solution mixed with cells affected cell-induced instability. At low flow rate ratio of GelMa to mineral oil below 0.200, stability was maintained regardless of GelMa concentration (5 and 8 wt. %) and cell presence, which led to uniform microdroplet generation. In contrast, instability at high flow rate ratio above 0.200 was worsened by cell presence and unstable jetting length, resulting in the generation of non-uniform cell-laden microdroplets. Therefore, the effect of cell-induced instability on microdroplet generation was minimized at a low flow rate ratio.

  4. Microfabricated photocrosslinkable polyelectrolyte-complex of chitosan and methacrylated gellan gum

    PubMed Central

    Coutinho, Daniela F.; Sant, Shilpa; Shakiba, Mojdeh; Wang, Ben; Gomes, Manuela E.; Neves, Nuno M.; Reis, Rui L.

    2012-01-01

    Chitosan (CHT) based polyelectrolyte complexes (PECs) have been receiving great attention for tissue engineering approaches. These hydrogels are held together by ionic forces and can be disrupted by changes in physiological conditions. In this study, we present a new class of CHT-based PEC hydrogels amenable to stabilization by chemical crosslinking. The photocrosslinkable anionic methacrylated gellan gum (MeGG) was complexed with cationic CHT and exposed to light, forming a PEC hydrogel. The chemical characterization of the photocrosslinkable PEC hydrogel by Fourier transform infrared spectroscopy (FTIR) revealed absorption peaks specific to the raw polymers. A significantly higher swelling ratio was observed for the PEC hydrogel with higher CHT content. The molecular interactions between both polysaccharides were evaluated chemically and microscopically, indicating the diffusion of CHT to the interior of the hydrogel. We hypothesized that the addition of MeGG to CHT solution first leads to a membrane formation around MeGG. Then, migration of CHT inside the MeGG hydrogel occurs to balance the electrostatic charges. The photocrosslinkable feature of MeGG further allowed the formation of cell-laden microscale hydrogel units with different shapes and sizes. Overall, this system is potentially useful for a variety of applications including the replication of microscale features of tissues for modular tissue engineering. PMID:23293429

  5. Direct-write Bioprinting of Cell-laden Methacrylated Gelatin Hydrogels

    PubMed Central

    Bertassoni, Luiz E.; Cardoso, Juliana C.; Manoharan, Vijayan; Cristino, Ana L.; Bhise, Nupura S.; Araujo, Wesleyan A.; Zorlutuna, Pinar; Vrana, Nihal E.; Ghaemmaghami, Amir M.

    2014-01-01

    Fabrication of three dimensional (3D) organoids with controlled microarchitectures has been shown to enhance tissue functionality. Bioprinting can be used to precisely position cells and cell-laden materials to generate controlled tissue architecture. Therefore, it represents an exciting alternative for organ fabrication. Despite the rapid progress in the field, the development of printing processes that can be used to fabricate macroscale tissue constructs from ECM-derived hydrogels has remained a challenge. Here we report a strategy for bioprinting of photolabile cell-laden methacrylated gelatin (GelMA) hydrogels. We bioprinted cell-laden GelMA at concentrations ranging from 7 to 15% with varying cell densities and found a direct correlation between printability and the hydrogel mechanical properties. Furthermore, encapsulated HepG2 cells preserved cell viability for at least 8 days following the bioprinting process. In summary, this work presents a strategy for direct-write bioprinting of a cell-laden photolabile ECM-derived hydrogel, which may find widespread application for tissue engineering, organ printing and the development of 3D drug discovery platforms. PMID:24695367

  6. Cell-induced flow-focusing instability in gelatin methacrylate microdroplet generation

    PubMed Central

    Jung, Jinmu; Oh, Jonghyun

    2014-01-01

    Photo-crosslinkable gelatin methacrylate (GelMa) microspheres are applicable to deliver cells or drugs in biological or biomedical applications. To fabricate GelMa microdroplets, a flow focusing technique with advantages of size control and rapid production was used in a T-junction microfluidic device. Instability played an important role in promoting microdroplet uniformity. 5 wt. % GelMa prepolymer solution mixed with cells affected cell-induced instability. At low flow rate ratio of GelMa to mineral oil below 0.200, stability was maintained regardless of GelMa concentration (5 and 8 wt. %) and cell presence, which led to uniform microdroplet generation. In contrast, instability at high flow rate ratio above 0.200 was worsened by cell presence and unstable jetting length, resulting in the generation of non-uniform cell-laden microdroplets. Therefore, the effect of cell-induced instability on microdroplet generation was minimized at a low flow rate ratio. PMID:24932318

  7. Gelatin methacrylate (GelMA) mediated electrochemical DNA biosensor for DNA hybridization.

    PubMed

    Topkaya, Seda Nur

    2015-02-15

    In this study, an electrochemical biosensor system for the detection of DNA hybridization by using gelatin methacrylate (GelMA) modified electrodes was developed. Electrochemical behavior of GelMA modified Pencil Graphite Electrode (PGE) that serve as a functional platform was investigated by using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) and compared with those of the bare PGE. Hybridization was achieved in solution phase and guanine oxidation signal changes were evaluated. The decrease in the guanine oxidation peak currents at around +1.0 V was used as an indicator for the DNA hybridization. Also, more interestingly GelMA intrinsic oxidation peaks at around +0.7 V changed substantially by immobilization of different oligonucleotides such as probe, hybrid and control sequences to the electrode surface. It is the first study of using GelMA as a part of an electrochemical biosensor system. The results are very promising in terms of using GelMA as a new DNA hybridization indicator. Additionally, GelMA modified electrodes could be useful for detecting ultra low quantity of oligonucleotides by providing mechanical support to the bio-recognition layer. The detection limit of this method is at present 10(-12)mol. Signal suppressions were increased from 50% to 93% for hybrid with using GelMA when it was compared to bare electrode which facilitates the hybridization detection.

  8. Synthesis and characterization of tunable poly(ethylene glycol): gelatin methacrylate composite hydrogels.

    PubMed

    Hutson, Che B; Nichol, Jason W; Aubin, Hug; Bae, Hojae; Yamanlar, Seda; Al-Haque, Shahed; Koshy, Sandeep T; Khademhosseini, Ali

    2011-07-01

    Poly(ethylene glycol) (PEG) hydrogels are popular for cell culture and tissue-engineering applications because they are nontoxic and exhibit favorable hydration and nutrient transport properties. However, cells cannot adhere to, remodel, proliferate within, or degrade PEG hydrogels. Methacrylated gelatin (GelMA), derived from denatured collagen, yields an enzymatically degradable, photocrosslinkable hydrogel that cells can degrade, adhere to and spread within. To combine the desirable features of each of these materials we synthesized PEG-GelMA composite hydrogels, hypothesizing that copolymerization would enable adjustable cell binding, mechanical, and degradation properties. The addition of GelMA to PEG resulted in a composite hydrogel that exhibited tunable mechanical and biological profiles. Adding GelMA (5%-15% w/v) to PEG (5% and 10% w/v) proportionally increased fibroblast surface binding and spreading as compared to PEG hydrogels (p<0.05). Encapsulated fibroblasts were also able to form 3D cellular networks 7 days after photoencapsulation only within composite hydrogels as compared to PEG alone. Additionally, PEG-GelMA hydrogels displayed tunable enzymatic degradation and stiffness profiles. PEG-GelMA composite hydrogels show great promise as tunable, cell-responsive hydrogels for 3D cell culture and regenerative medicine applications.

  9. Evaluation of polymethyl methacrylate resin mechanical properties with incorporated halloysite nanotubes

    PubMed Central

    2016-01-01

    PURPOSE This study inspects the effect of incorporating halloysite nanotubes (HNTs) into polymethyl methacrylate (PMMA) resin on its flexural strength, hardness, and Young's modulus. MATERIALS AND METHODS Four groups of acrylic resin powder were prepared. One group without HNTs was used as a control group and the other three groups contained 0.3, 0.6 and 0.9 wt% HNTs. For each one, flexural strength, Young's modulus and hardness values were measured. One-way ANOVA and Tukey's test were used for comparison (P<.05). RESULTS At lower concentration (0.3 wt%) of HNT, there was a significant increase of hardness values but no significant increase in both flexural strength and Young's modulus values of PMMA resin. In contrast, at higher concentration (0.6 and 0.9 wt%), there was a significant decrease in hardness values but no significant decrease in flexural strength and Young's modulus values compared to those of the control group. CONCLUSION Addition of lower concentration of halloysite nanotubes to denture base materials could improve some of their mechanical properties. Improving the mechanical properties of acrylic resin base material could increase the patient satisfaction. PMID:27350849

  10. Development characteristics of polymethyl methacrylate in alcohol/water mixtures. A lithography and Raman spectroscopy study

    SciTech Connect

    Ocola, Leonidas E.; Costales, Maya; Gosztola, David J.

    2015-12-10

    Poly methyl methacrylate (PMMA) is the most widely used resist in electron beam lithography. This paper reports on a lithography and Raman spectroscopy study of development characteristics of PMMA in methanol, ethanol and isopropanol mixtures with water as developers. We have found that ethanol/water mixtures at a 4:1 volume ratio are an excellent, high resolution, non-toxic, developer for exposed PMMA. We also have found that the proper methodology to use so that contrast data can be compared to techniques used in polymer science is not to rinse the developed resist but to immediately dry with nitrogen. Our results show how powerful simple lithographic techniques can be used to study ternary polymer solvent solutions when compared to other techniques used in the literature. Raman data shows that there both tightly bonded –OH groups and non-hydrogen bonded –OH groups play a role in the development of PMMA. Tightly hydrogen bonded –OH groups show pure Lorentzian Raman absorption only in the concentration ranges where ethanol/water and IPA/water mixtures are effective developers of PMMA. The impact of the understanding these interactions may open doors to a new developers of other electron beam resists that can reduce the toxicity of the waste stream.

  11. Self-assembled rosette nanotubes and poly(2-hydroxyethyl methacrylate) hydrogels promote skin cell functions.

    PubMed

    Sun, Linlin; Li, Dongni; Hemraz, Usha D; Fenniri, Hicham; Webster, Thomas J

    2014-10-01

    The next generation skin of wound healing materials should stimulate skin regeneration by actively promoting appropriate cellular adhesion and proliferation. As materials with novel self-assembling and solidification properties when transitioning from room to body temperatures, rosette nanotubes (RNTs) may be such a proactive material. RNTs resemble naturally occurring nanostructures in the skin (such as collagen and keratin) assembling with noncovalent forces in physiological environments. Presenting desirable bioactive properties, RNTs have been used for various tissue engineering applications including increasing in vivo bone and cartilage regeneration. The objective of the current in vitro study was, for the first time, to improve properties of a commonly used hydrogel (poly(2-hydroxyethyl methacrylate) or pHEMA) for skin regeneration by incorporating one type of novel self-assembled RNTs, called TBL. Results showed for the first time increased keratinocyte and fibroblast proliferation on hydrogels coated with TBLs compared to those not coated with TBL. In this manner, this study provides the first evidence that TBL RNTs are promising for wound healing applications due to their optimal cytocompatibility, solidification, and mechanical properties and, thus, should be further studied for such applications.

  12. Beam waist position study for surface modification of polymethyl-methacrylate with femtosecond laser pulses

    NASA Astrophysics Data System (ADS)

    Caballero-Lucas, F.; Florian, C.; Fernández-Pradas, J. M.; Morenza, J. L.; Serra, P.

    2016-06-01

    Femtosecond lasers are versatile tools to process transparent materials. This optical property poses an issue for surface modification. In this case, laser radiation would not be absorbed at the surface unless the beam is just focused there. Otherwise, absorption would take place in the bulk leaving the surface unperturbed. Therefore, strategies to position the material surface at the laser beam waist with high accuracy are essential. We investigated and compared two options to achieve this aim: the use of reflectance data and transmittance measurements across the sample, both obtained during z-scans with pulses from a 1027 nm wavelength laser and 450 fs pulse duration. As the material enters the beam waist region, a reflectance peak is detected while a transmittance drop is observed. With these observations, it is possible to control the position of the sample surface with respect to the beam waist with high resolution and attain pure surface modification. In the case of polymethyl-methacrylate (PMMA), this resolution is 0.6 μm. The results prove that these methods are feasible for submicrometric processing of the surface.

  13. Biomolecular functionalization for enhanced cell–material interactions of poly(methyl methacrylate) surfaces

    PubMed Central

    Punet, Xavier; Mauchauffé, Rodolphe; Rodríguez-Cabello, José C.; Alonso, Matilde; Engel, Elisabeth; Mateos-Timoneda, Miguel A.

    2015-01-01

    The integration of implants or medical devices into the body tissues requires of good cell–material interactions. However, most polymeric materials used for these applications lack on biological cues, which enhanced mid- and long-term implant failure due to weak integration with the surrounding tissue. Commonly used strategies for tissue–material integration focus on functionalization of the material surface by means of natural proteins or short peptides. However, the use of these biomolecules involves major drawbacks such as immunogenic problems and oversimplification of the constructs. Here, designed elastin-like recombinamers (ELRs) are used to enhance poly(methyl methacrylate) surface properties and compared against the use of short peptides. In this study, cell response has been analysed for different functionalization conditions in the presence and absence of a competing protein, which interferes on surface–cell interaction by unspecific adsorption on the interface. The study has shown that ELRs can induce higher rates of cell attachment and stronger cell anchorages than short peptides, being a better choice for surface functionalization. PMID:26816640

  14. Development of sustained antimicrobial-release systems using poly(2-hydroxyethyl methacrylate)/trimethylolpropane trimethacrylate hydrogels.

    PubMed

    Kitagawa, Haruaki; Takeda, Kahoru; Kitagawa, Ranna; Izutani, Naomi; Miki, Saeki; Hirose, Nanako; Hayashi, Mikako; Imazato, Satoshi

    2014-10-01

    Reconstructive materials with sustained antimicrobial effects could be useful for preventing infectious diseases in an environment containing indigenous bacteria or fungi such as the oral cavity. With the objective of applying a non-biodegradable hydrogel to resin-based materials as a reservoir for water-soluble antimicrobials, novel hydrogels consisting of 2-hydroxyethyl methacrylate (HEMA) and trimethylolpropane trimethacrylate (TMPT) were fabricated. Cetylpyridinium chloride (CPC) was loaded into five hydrogels comprising different ratios of HEMA/TMPT, and their ability to release as well as to be recharged with CPC was examined in vitro. A polyHEMA/TMPT hydrogel comprising 50% HEMA/50% TMPT could be effectively loaded and recharged with CPC by immersion into a CPC solution, demonstrating the longest release of CPC, above the concentration required to inhibit bacteria and fungi. The binding of CPC to the hydrogels was mainly through hydrophobic interaction. Loading of CPC into a hydrogel by mixing CPC powder with the HEMA/TMPT monomer before polymerization resulted in marked extension of the initial CPC-release period. The CPC-pre-mixed hydrogel was confirmed to exhibit antibacterial activity by agar diffusion tests. It is possible to achieve a sustained release system for antimicrobials by pre-mix loading and recharging CPC into a 50% HEMA/50% TMPT hydrogel.

  15. Customized Cranioplasty Implants Using Three-Dimensional Printers and Polymethyl-Methacrylate Casting

    PubMed Central

    Kim, Bum-Joon; Hong, Ki-Sun; Park, Kyung-Jae; Park, Dong-Hyuk; Chung, Yong-Gu

    2012-01-01

    Objective The prefabrication of customized cranioplastic implants has been introduced to overcome the difficulties of intra-operative implant molding. The authors present a new technique, which consists of the prefabrication of implant molds using three-dimensional (3D) printers and polymethyl-methacrylate (PMMA) casting. Methods A total of 16 patients with large skull defects (>100 cm2) underwent cranioplasty between November 2009 and April 2011. For unilateral cranial defects, 3D images of the skull were obtained from preoperative axial 1-mm spiral computed tomography (CT) scans. The image of the implant was generated by a digital subtraction mirror-imaging process using the normal side of the cranium as a model. For bilateral cranial defects, precraniectomy routine spiral CT scan data were merged with postcraniectomy 3D CT images following a smoothing process. Prefabrication of the mold was performed by the 3D printer. Intraoperatively, the PMMA implant was created with the prefabricated mold, and fit into the cranial defect. Results The median operation time was 184.36±26.07 minutes. Postoperative CT scans showed excellent restoration of the symmetrical contours and curvature of the cranium in all cases. The median follow-up period was 23 months (range, 14-28 months). Postoperative infection was developed in one case (6.2%) who had an open wound defect previously. Conclusion Customized cranioplasty PMMA implants using 3D printer may be a useful technique for the reconstruction of various cranial defects. PMID:23346326

  16. Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

    PubMed

    Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

    2006-09-01

    An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods. PMID:16736086

  17. Tailoring the morphology of methacrylate ester-based monoliths for optimum efficiency in liquid chromatography.

    PubMed

    Eeltink, Sebastiaan; Herrero-Martinez, José Manuel; Rozing, Gerard P; Schoenmakers, Peter J; Kok, Wim Th

    2005-11-15

    Methacrylate ester-based monolithic stationary phases were prepared in situ in fused-silica capillaries and simultaneously in vials. The influence of the composition of the polymerization mixture on the morphology was studied with mercury intrusion porosimetry, scanning electron microscopy, and nitrogen adsorption measurements. A high-density porous polymeric material with a unimodal pore-size distribution was prepared with 40 wt % monomers and 60 wt % solvent in the mixture. A low-density material, prepared with a 20:80 ratio of monomers versus pore-forming solvent, showed a bimodal pore-size distribution and a much finer structure than the high-density monolith. The characteristic pore size could be controlled by changing the ratio of pore-forming solvents. With increasing solvent polarity, both the pore size and the dimension of the globules increased. The best efficiency in the CEC mode was obtained with an average pore size of 600 nm. Low-density monoliths exhibited lower A- and C-terms than high-density monoliths. With the optimal monolithic material, a minimum plate height of 5 mum could be obtained. The low-density monolith also performed better in the HPLC mode, giving a minimum plate height of 15 mum and a much higher flow permeability than that of the high-density material. PMID:16285684

  18. Transfection of immortalized keratinocytes by low toxic poly(2-(dimethylamino)ethyl methacrylate)-based polymers.

    PubMed

    Van Overstraeten-Schlögel, Nancy; Ho-Shim, Yong; Tevel, Virginie; Bontems, Sébastien; Dubois, Philippe; Raes, Martine

    2012-01-01

    Skin carcinoma are among the most spread diagnosed tumours in the world. In this study, we investigated the transfection of immortalized keratinocytes, used as an in vitro model for skin carcinoma, using antisense technology and poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA)-based polymers, with original architecture and functionalities. We tested PDMAEMA polymers with different structures: linear, with two (DEA-PDMAEMA) or three (TEA-PDMAEMA) arms. The cytotoxicity of these polymers was assessed over a wide range of apparent M n (from 7600 to 64 600). At a N/P ratio of 7.38, cytotoxicity increases with the M n. Keratinocytes were transfected with a fluorescent oligonucleotide and then analyzed by flow cytometry. For the three architectures tested, the percentage of transfected cells and abundance of internalized oligonucleotide were closely related to the M n of the polymer. Confocal microscopy and FACS analyses showed a wide spread fine granular distribution of the oligonucleotide up to 3 days post-transfection. Then, we assessed the silencing efficiency of the polymers, targeting GFP in GFP expressing keratinocytes. The maximal silencing effect (±40%) was obtained using a DEA-PDMAEMA polymer (M n = 30 300). These results suggest that PDMAEMA-based polymers can be efficiently used to transfect immortalized keratinocytes and, thus, open new perspectives in the therapy of skin carcinoma.

  19. Radiation effects on poly(methyl methacrylate) induced by pulsed laser irradiations

    NASA Astrophysics Data System (ADS)

    Torrisi, L.; Italiano, A.; Amato, E.; Caridi, F.; Cutroneo, M.; Squeri, C. A.; Squeri, G.; Roszkowska, A. M.

    2012-09-01

    Poly(methyl methacrylate) (PMMA) was irradiated using a medical UV-ArF excimer laser operating at the fundamental wavelength of 193 nm. Characterized by a beam diameter of 1.8 mm and energy of 180 mJ with a Gaussian energy profile, it operates in a single mode or at 30 Hz repetition rate. Mechanical profilometry was carried out on ablation craters in order to study the rugosity and the ablation yield in the various operative conditions. Optical transmission and reflection measurements at six wavelengths were conducted in order to characterize the optical properties of the irradiated surfaces. Measured crater depths in PMMA were lower with respect to the forecasted ones in corneal tissue, while the lateral crater aperture was maintained. The rugosity produced at the crater bottom after irradiation was about 0.3 μm, and the ablation yield was about 1015 molecules/laser pulse, while etching depth and diameter show a roughly linear dependence on the number of laser shots. These experiments constitute a base for deeper clinical investigations.

  20. Olfactory function in chemical workers exposed to acrylate and methacrylate vapors.

    PubMed

    Schwartz, B S; Doty, R L; Monroe, C; Frye, R; Barker, S

    1989-05-01

    An investigation of the olfactory function of 731 workers at a chemical facility which manufacturers acrylates and methacrylates was undertaken using a standardized quantitative test. In a cross-sectional analysis of the data, no associations of chemical exposure with olfactory test scores were observed. A nested case-control study designed to evaluate the cumulative effects of exposure on olfactory function, however, revealed elevated crude exposure odds ratios (95% confidence interval) of 2.0 (1.1, 3.8) for all workers and 6.0 (1.7, 21.5) for workers who never smoked cigarettes. Logistic regression analysis, adjusting for multiple confounders, revealed exposure odds ratios of 2.8 (1.1, 7.0) and 13.5 (2.1, 87.6) in these same groups, respectively, and a dose-response relationship between olfactory dysfunction and cumulative exposure scores--semi-quantitative indices of lifetime exposure to the acrylates. The data also revealed decreasing exposure odds ratios with increasing duration since last exposure to these chemicals, suggesting that the effects may be reversible. PMID:2784947

  1. Chemically modified poly(2-hydroxyethyl methacrylate) cryogel for the adsorption of heparin.

    PubMed

    La Spina, R; Tripisciano, C; Mecca, T; Cunsolo, F; Weber, V; Mattiasson, B

    2014-08-01

    Various clinical procedures, such as cardiovascular surgery or extracorporeal blood purification, involve systemic anticoagulation using heparin. High concentrations of circulating heparin require neutralization due to possible serious bleeding complications. The intravenous administration of the heparin antagonist protamine sulfate is routinely clinically performed, but is frequently associated with adverse reactions. Therefore, there is a need for a valid and safe alternative to achieve extracorporeal heparin removal from blood or plasma, such as a filter, a matrix, or an adsorbent. Here, we describe the development of a macroporous poly(2-hydroxyethyl methacrylate)-based monolithic cryogel functionalized with l-lysine (pHEMA-lys) and the characterization of its selective heparin adsorption. The maximum binding capacity was quantified in vitro using aqueous and serum solutions under static and dynamic conditions, and fresh human plasma under static conditions. The pHEMA-lys bound 40,500 IU and 32,500 IU heparin/g cryogel at the equilibrium in aqueous solution and 50% serum, respectively. In human plasma spiked with 100 IU/mL of heparin, the binding was still highly efficient (4330 IU/g cryogel after 30 min, i.e., 87% of the initial concentration). The cryogels showed good blood compatibility, as indicated by negligible adsorption of albumin, antithrombin III, and total protein, and may thus be suitable for extracorporeal heparin removal. PMID:24425361

  2. Dual-Crosslinked Methacrylated Alginate Sub-Microspheres for Intracellular Chemotherapeutic Delivery

    PubMed Central

    Scherrer, Ryan M.; Oldinski, Rachael A.

    2016-01-01

    Intracellular delivery vehicles comprised of methacrylated alginate (Alg-MA) were developed for the internalization and release of doxorubicin hydrochloride (DOX). Alg-MA was synthesized via an anhydrous reaction, and a mixture of Alg-MA and DOX was formed into sub-microspheres using a water/oil emulsion. Covalently crosslinked sub-microspheres were formed via exposure to green light, in order to investigate effects of crosslinking on drug release and cell internalization, compared to traditional techniques such as ultra violet (UV) light. Crosslinking was performed using light exposure alone, or in combination with ionic crosslinking using calcium chloride (CaCl2). Alg-MA sub-microsphere diameters were between 88 – 617 nm, and zeta-potentials were between −20 and −37 mV. Using human lung epithelial carcinoma cells (A549s) as a model, cellular internalization was confirmed using flow cytometry; different sub-microsphere formulations varied the efficiency of internalization, with UV-crosslinked sub-microspheres achieving the highest internalization percentages. While blank (non-loaded) Alg-MA sub-microspheres were non-cytotoxic to A549s, DOX-loaded sub-microspheres significantly reduced mitochondrial activity after five days of culture. Photo-crosslinked Alg-MA sub-microspheres may be a potential chemotherapeutic delivery system for cancer treatment. PMID:27378419

  3. Dual-crosslinked oxidized, methacrylated alginate/PEG hydrogels for bioadhesive applications

    PubMed Central

    Jeon, Oju; Samorezov, Julia E.; Alsberg, Eben

    2013-01-01

    A degradable, cytocompatible bioadhesive can facilitate surgical procedures and minimize patient pain and postsurgical complications. In this study, a bioadhesive hydrogel system based on oxidized, methacrylated alginate/8-arm poly(ethylene glycol) amine (OMA/PEG) has been developed, and the bioadhesive characteristics of the crosslinked OMA/PEG hydrogels are evaluated. Here, we demonstrate that the swelling behavior, degradation profiles, and storage moduli of crosslinked OMA/PEG hydrogels are tunable by varying the degree of alginate oxidation. The crosslinked OMA/PEG hydrogels exhibit cytocompatibility when cultured with human bone marrow-derived mesenchymal stem cells. In addition, the adhesion strength of these hydrogels, controllable by varying the alginate oxidation level and measured using a porcine skin model, is superior to commercially available fibrin glue. This OMA/PEG hydrogel system with controllable biodegradation and mechanical properties and adhesion strength may be a promising bioadhesive for clinical use in biomedical applications, such as drug delivery, wound closure and healing, biomedical device implantation, and tissue engineering. PMID:24035886

  4. Sustained release of antibiotic from poly(2-hydroxyethyl methacrylate) to prevent blinding infections after cataract surgery

    PubMed Central

    Anderson, Erin M.; Noble, Misty L.; Garty, Shai; Ma, Hongyan; Bryers, James D.; Shen, Tueng T.; Ratner, Buddy D.

    2010-01-01

    Intraocular lens implantation after opacified natural lens removal is the primary treatment for cataracts in developed countries. Cataract surgery is generally considered safe, but entails significant risks in countries where sophisticated sterile operating theaters are not widely available. Post-operative infection (endophthalmitis) is a potential blinding complication. Infection often results from bacterial colonization of the new lens implant and subsequent antibiotic-tolerant biofilm formation. To combat this risk, we developed a polymeric hydrogel system that can deliver effective levels of antibiotic over an extended period of time within the globe of the eye. Norfloxacin™ antibiotic was loaded into cross-linked poly(2-hydroxyethyl methacrylate) (pHEMA) gels, which were subsequently surface-modified with octadecyl isocyanate to produce a hydrophobic rate-limiting barrier controlling norfloxacin release. Octadecyl surface modification was characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). A 15-min modification leads to a uniform surface coating and near zero order release of norfloxacin from the matrix. Norfloxacin released from coated pHEMA kills Staphylococcus epidermidis in suspension and on a simulated medical implant surface. With these data, we demonstrate a new and effective system for sustained drug release from a hydrogel matrix with specific application for intraocular lens surgery. PMID:19631376

  5. Superparamagnetic poly(methyl methacrylate) beads for nattokinase purification from fermentation broth.

    PubMed

    Yang, Chengli; Xing, Jianmin; Guan, Yueping; Liu, Huizhou

    2006-09-01

    An effective method for purification of nattokinase from fermentation broth using magnetic poly(methyl methacrylate) (PMMA) beads immobilized with p-aminobenzamidine was proposed in this study. Firstly, magnetic PMMA beads with a narrow size distribution were prepared by spraying suspension polymerization. Then, they were highly functionalized via transesterification reaction with polyethylene glycol. The surface hydroxyl-modified magnetic beads obtained were further modified with chloroethylamine to transfer the surface amino-modified magnetic functional beads. The morphology and surface functionality of the magnetic beads were examined by scanning electron microscopy and Fourier transform infrared. An affinity ligand, p-aminobenzamidine was covalently immobilized to the amino-modified magnetic beads by the glutaraldehyde method for nattokinase purification directly from the fermentation broth. The purification factor and the recovery of the enzyme activity were found to be 8.7 and 85%, respectively. The purification of nattokinase from fermentation broth by magnetic beads only took 40 min, which shows a very fast purification of nattokinase compared to traditional purification methods.

  6. A Sol-Gel-Modified Poly(methyl methacrylate) Electrophoresis Microchip with a Hydrophilic Channel Wall

    SciTech Connect

    Chen, Gang; Xu, Xuejiao; Lin, Yuehe; Wang, Joseph

    2007-07-27

    A sol-gel method was employed to fabricate a poly(methyl methacrylate) (PMMA) electrophoresis microchip that contains a hydrophilic channel wall. To fabricate such a device, tetraethoxysilane (TEOS) was injected into the PMMA channel and was allowed to diffuse into the surface layer for 24 h. After removing the excess TEOS, the channel was filled with an acidic solution for 3 h. Subsequently, the channel was flushed with water and was pretreated in an oven to obtain a sol-gel-modified PMMA microchip. The water contact angle for the sol-gel-modified PMMA was 27.4° compared with 66.3° for the pure PMMA. In addition, the electro-osmotic flow increased from 2.13×10-4 cm2 V-1 s-1 for the native-PMMA channel to 4.86×10-4 cm2 V-1 s-1 for the modified one. The analytical performance of the sol-gel-modified PMMA microchip was demonstrated for the electrophoretic separation of several purines, coupled with amperometric detection. The separation efficiency of uric acid increased to 74 882.3 m-1 compared with 14 730.5 m-1 for native-PMMA microchips. The result of this simple modification is a significant improvement in the performance of PMMA for microchip electrophoresis and microfluidic applications.

  7. Photo-cross-linkable methacrylated gelatin and hydroxyapatite hybrid hydrogel for modularly engineering biomimetic osteon.

    PubMed

    Zuo, Yicong; Liu, Xiaolu; Wei, Dan; Sun, Jing; Xiao, Wenqian; Zhao, Huan; Guo, Likun; Wei, Qingrong; Fan, Hongsong; Zhang, Xingdong

    2015-05-20

    Modular tissue engineering holds great potential in regenerating natural complex tissues by engineering three-dimensional modular scaffolds with predefined geometry and biological characters. In modular tissue-like construction, a scaffold with an appropriate mechanical rigidity for assembling fabrication and high biocompatibility for cell survival is the key to the successful bioconstruction. In this work, a series of composite hydrogels (GH0, GH1, GH2, and GH3) based on a combination of methacrylated gelatin (GelMA) and hydroxyapatite (HA) was exploited to enhance hydrogel mechanical rigidity and promote cell functional expression for osteon biofabrication. These composite hydrogels presented a lower swelling ratio, higher mechanical moduli, and better biocompatibility when compared to the pure GelMA hydrogel. Furthermore, on the basis of the composite hydrogel and photolithograph technology, we successfully constructed an osteon-like concentric double-ring structure in which the inner ring encapsulating human umbilical vascular endothelial cells (HUVECs) was designed to imitate blood vessel tubule while the outer ring encapsulating human osteoblast-like cells (MG63s) acts as part of bone. During the coculture period, MG63s and HUVECs exhibited not only satisfying growth status but also the enhanced genic expression of osteogenesis-related and angiogenesis-related differentiations. These results demonstrate this GelMA-HA composite hydrogel system is promising for modular tissue engineering.

  8. Comparison of computed tomography dose index in polymethyl methacrylate and nylon dosimetry phantoms.

    PubMed

    Sookpeng, Supawitoo; Cheebsumon, Patsuree; Pengpan, Thanyawee; Martin, Colin

    2016-01-01

    The use of computed tomography (CT) scanning has been growing steadily. Therefore, CT dose measurement is becoming increasingly important for patient protection and optimization. A phantom is an important tool for dose measurement. This paper focuses on the evaluation of a CT dosimetry phantom made from nylon, instead of the standard polymethyl methacrylate (PMMA), which is not readily available or is too expensive in some countries. Comparison between phantoms made from the two materials is made in terms of measurements of the CT dose indices (CTDI). These were measured for four different beam widths and kVp settings at the center and periphery in head and body phantoms made from both materials and weighted CTDIs (CTDIw) were calculated. CT numbers along the z-axis of the phantom were also measured at the center and four peripheral positions of each scanned slice to check phantom homogeneity. Results showed that values for the CTDIw measured in the nylon phantoms were slightly higher than those from the PMMA while CT numbers for nylon were lower than those of PMMA. This is because the mass attenuation coefficient of the nylon is higher. Nylon could be used as a substitute material for CT dosimetry phantom to enable measurements and adjustment factors are given which could be used to estimate PMMA values for making comparisons with displayed values. PMID:27051170

  9. Comparison of shape recovery ratios of single-piece poly(methyl methacrylate) intraocular lens haptics.

    PubMed

    Kimura, W; Kimura, T; Sawada, T; Kikuchi, T; Nagai, H; Yamada, Y

    1993-09-01

    We studied shape recovery ratios of several single- and three-piece intraocular lens (IOL) haptics after conducting compression tests for various lengths of time. Results of the comparison of poly(methyl methacrylate) (PMMA) IOL haptics configured of a single piece and of three pieces showed a superior shape recovery ratio for single-piece haptics. Comparisons of the shape recovery ratios among single-piece PMMA haptics and conventional three-piece haptics made of polyvinylidene fluoride (PVDF), PMMA, and polypropylene (PP) revealed that the shape recovery ratio of single-piece PMMA haptics was higher than the ratios of the conventional three-piece PMMA and PP haptics. The ratios of two of three of the single-piece PMMA haptics, however, were lower than the ratios of three-piece PVDF haptics. The form and manufacturing procedures of haptics likely have a significant impact on the shape recovery ratio of haptics, even those made of the same material. Since decentration after IOL surgery could be caused by the condition of the patient's lenticular capsule and Zinn's zonule, it is difficult to conclude that the shape recovery ratio is the only factor in IOL stability. Nevertheless, this study indicates that IOL haptics that cause less decentration and have better mechanical properties should be developed.

  10. Sustained release of antibiotic from poly(2-hydroxyethyl methacrylate) to prevent blinding infections after cataract surgery.

    PubMed

    Anderson, Erin M; Noble, Misty L; Garty, Shai; Ma, Hongyan; Bryers, James D; Shen, Tueng T; Ratner, Buddy D

    2009-10-01

    Intraocular lens implantation after opacified natural lens removal is the primary treatment for cataracts in developed countries. Cataract surgery is generally considered safe, but entails significant risks in countries where sophisticated sterile operating theaters are not widely available. Post-operative infection (endophthalmitis) is a potential blinding complication. Infection often results from bacterial colonization of the new lens implant and subsequent antibiotic-tolerant biofilm formation. To combat this risk, we developed a polymeric hydrogel system that can deliver effective levels of antibiotic over an extended period of time within the globe of the eye. Norfloxacin antibiotic was loaded into cross-linked poly(2-hydroxyethyl methacrylate) (pHEMA) gels, which were subsequently surface-modified with octadecyl isocyanate to produce a hydrophobic rate-limiting barrier controlling norfloxacin release. Octadecyl surface modification was characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). A 15-min modification leads to a uniform surface coating and near zero order release of norfloxacin from the matrix. Norfloxacin released from coated pHEMA kills Staphylococcus epidermidis in suspension and on a simulated medical implant surface. With these data, we demonstrate a new and effective system for sustained drug release from a hydrogel matrix with specific application for intraocular lens surgery.

  11. Blend miscibility of cellulose propionate with poly(N-vinyl pyrrolidone-co-methyl methacrylate).

    PubMed

    Sugimura, Kazuki; Teramoto, Yoshikuni; Nishio, Yoshiyuki

    2013-10-15

    The blend miscibility of cellulose propionate (CP) with poly(N-vinyl pyrrolidone-co-methyl methacrylate) (P(VP-co-MMA)) was investigated. The degree of substitution (DS) of CP used ranged from 1.6 to >2.9, and samples for the vinyl polymer component were prepared in a full range of VP:MMA compositions. Through DSC analysis and solid-state (13)C NMR and FT-IR measurements, we revealed that CPs of DS<2.7 were miscible with P(VP-co-MMA)s of VP≥~10mol% on a scale within a few nanometers, in virtue of hydrogen-bonding interactions between CP-hydroxyls and VP-carbonyls. When the DS of CP exceeded 2.7, the miscibility was restricted to the polymer pairs using P(VP-co-MMA)s of VP=ca. 10-40 mol%; the scale of mixing in the blends concerned was somewhat larger (ca. 5-20 nm), however. The appearance of such a "miscibility window" was interpretable as an effect of intramolecular repulsion in the copolymer component. Results of DMA and birefringence measurements indicated that the miscible blending of CP with the vinyl polymer invited synergistic improvements in thermomechanical and optical properties of the respective constituent polymers. Additionally, it was found that the VP:MMA composition range corresponding to the miscibility window was expanded by modification of the CP component into cellulose acetate propionate. PMID:23987378

  12. Nonlinear optical properties of poly(methyl methacrylate) thin films doped with Bixa Orellana dye

    NASA Astrophysics Data System (ADS)

    Zongo, S.; Kerasidou, A. P.; Sone, B. T.; Diallo, A.; Mthunzi, P.; Iliopoulos, K.; Nkosi, M.; Maaza, M.; Sahraoui, B.

    2015-06-01

    Natural dyes with highly delocalized π-electron systems are considered as promising organic materials for nonlinear optical applications. Among these dyes, Bixa Orellana dye with extended π-electron delocalization is one of the most attractive dyes. Bixa Orellana dye-doped Poly(methyl methacrylate) (PMMA) thin films were prepared through spin coating process for linear and nonlinear optical properties investigation. Atomic force microscopy (AFM) was used to evaluate the roughness of the thin films. The optical constants n and k were evaluated by ellipsometric spectroscopy. The refractive index had a maximum of about 1.456 at 508.5, 523.79 and 511.9 nm, while the maximum of k varies from 0.070 to 0.080 with the thickness. The third order nonlinear optical properties of the hybrid Bixa Orellana dye-PMMA polymer were investigated under 30 ps laser irradiation at 1064 nm with a repetition rate of 10 Hz. In particular the third-order nonlinear susceptibility has been determined by means of the Maker Fringes technique. The nonlinear third order susceptibility was found to be 1.00 × 10-21 m2 V-2 or 0.72 × 10-13 esu. Our studies provide concrete evidence that the hybrid-PMMA composites of Bixa dye are prospective candidates for nonlinear material applications.

  13. Modification of flax fibres by radiation induced emulsion graft copolymerization of glycidyl methacrylate

    NASA Astrophysics Data System (ADS)

    Moawia, Rihab Musaad; Nasef, Mohamed Mahmoud; Mohamed, Nor Hasimah; Ripin, Adnan

    2016-05-01

    Flax fibres were modified by radiation induced graft copolymerization of glycidyl methacrylate (GMA) by pre-irradiation method in an emulsion medium. The effect of reaction parameters on the degree of grafting (DOG) such as concentration of bleaching agent, absorbed dose, monomer concentration, temperature and reaction time were investigated. The DOG was found to be dependent on the investigated parameters. The incorporation of poly(GMA) grafts in the bleached flax fibres was confirmed by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The structural and mechanical changes were evaluated by X-ray diffraction (XRD) and mechanical tester, respectively. The results revealed that reacting bleached flax fibres irradiated with 20 kGy with 5% GMA emulsion containing 0.5% polyoxyethylene-sorbitan monolaurate (Tween 20) surfactant at 40 °C for 1 h led to a maximum DOG of 148%. The grafted fibres showed sufficient mechanical strength and hydrophobicity which make them promising precursors for development of adsorbents after appropriate chemical treatments.

  14. Lithography exposure characteristics of poly(methyl methacrylate) (PMMA) for carbon, helium and hydrogen ions

    NASA Astrophysics Data System (ADS)

    Puttaraksa, Nitipon; Norarat, Rattanaporn; Laitinen, Mikko; Sajavaara, Timo; Singkarat, Somsorn; Whitlow, Harry J.

    2012-02-01

    Poly(methyl methacrylate) is a common polymer used as a lithographic resist for all forms of particle (photon, ion and electron) beam writing. Faithful lithographic reproduction requires that the exposure dose, Θ, lies in the window Θ0⩽Θ<Θ, where Θ0 and Θ represent the clearing and cross-linking onset doses, respectively. In this work we have used the programmable proximity aperture ion beam lithography systems in Chiang Mai and Jyväskylä to determine the exposure characteristics in terms of fluence for 2 MeV protons, 3 MeV 4He and 6 MeV 12C ions, respectively. After exposure the samples were developed in 7:3 by volume propan-2-ol:de-ionised water mixture. At low fluences, where the fluence is below the clearing fluence, the exposed regions were characterised by rough regions, particularly for He with holes around the ion tracks. As the fluence (dose) increases so that the dose exceeds the clearing dose, the PMMA is uniformly removed with sharp vertical walls. When Θ exceeds the cross-linking onset fluence, the bottom of the exposed regions show undissolved PMMA.

  15. Influence of surface treatments to repair recent fillings of silorane-and methacrylate-based composites

    PubMed Central

    Kaneko, Marina; Caldas, Ricardo Armini; Feitosa, Victor Pinheiro; Xediek Consani, Rafael Leonardo; Schneider, Luis Felipe J.; Bacchi, Ataís

    2015-01-01

    Purpose: The aim of this study was to evaluate the tensile bond strength (TBS) of repairs in recent fillings of methacrylate- (MBC) or silorane-based composites (SBC) subsequent to different surface treatments. Materials and Methods: Fifty slabs of Filtek P60 (3M ESPE, St Paul, USA) and Filtek P90 (3M ESPE) were stored for 10 days in distilled water at 37°C. The surface of adhesion was abraded with a 600-grit silicone paper and repaired using each respective composite: G1, no treatment (control); G2, application of adhesive; G3, application of silane and adhesive; G4, sandblasting (Al2O3) and adhesive; and G5, sandblasting (Al2O3), silane, and adhesive. Further 10 slabs of each composite were also evaluated for cohesive strength (G6). After 30 days immersion in distilled water at 37°C, the TBS was determined. Results: TBS results were higher for MBC than for SBC (P = 0.00012). The experimental groups were similar for SBC and the TBS was 27% of its cohesive strength. For P60, sandblasting significantly improved the TBS compared to other groups. With MBC, G4 and G5, the TBS was approximately 47% of its cohesive strength. Conclusion: Sandblasting (Al2O3) improves the repair-strength of MBC, whilst for the SBC all treatments succeed. MBC presents higher repair strength than SBC. PMID:26069413

  16. Highly active ppm level organic copper catalyzed photo-induced ICAR ATRP of methyl methacrylate.

    PubMed

    Jiang, Xiaowu; Wu, Jian; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2014-11-01

    A novel photo-induced homogeneous atom transfer radical polymerization (ATRP) system is constructed using an organic copper salt (Cu(SC(S)N(C2 H5 )2 )2 ) as a photo-induced catalyst at 30 °C. Herein, N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA) is used as a ligand, ethyl 2-bromophenylacetate (EBPA) as an ATRP initiator, and (2,4,6-trimethylbenzoyl) diphenylphosphine oxide (TPO) as a photo-induced radical initiator to establish an ICAR (initiators for continuous activator regeneration) ATRP using methyl methacrylate (MMA) as a modal monomer. The effect of the concentration of the organic copper on the polymerization is investigated in detail. It is found that well-controlled polymerization can be obtained even with the amount of (Cu(SC(S)N(C2 H5 )2 )2 decreasing to a 1.56 ppm level, with the molecular weight of the resultant polymers increasing linearly with monomer conversion while maintaining a narrow molecular weight distribution (M¯w/M¯n < 1.3). PMID:25250767

  17. AGING OF ADHESIVE INTERFACES TREATED WITH BENZALKONIUM CHLORIDE AND BENZALKONIUM METHACRYLATE

    PubMed Central

    Sabatini, Camila; Pashley, David H.

    2015-01-01

    Inhibition of endogenous dentin matrix metalloproteinases (MMPs) within incompletely infiltrated hybrid layers can contribute to the preservation of resin-dentin bonds. This study evaluated the bond stability of interfaces treated with benzalkonium chloride (BAC) and benzalkonium methacrylate (MBAC), and its inhibitory properties in dentin MMP activity. Single-component adhesive ALL-BOND UNIVERSAL, modified with BAC or MBAC in concentrations of 0, 0.5, 1.0 and 2.0% was used for microtensile bond strength (μTBS) evaluation after 24 h, 6 months and 1 yr. Human dentin beams were treated with 37% phosphoric acid, dipped either in 0.5% BAC, 1.0% BAC or water (control) for 60 s and then incubated in SensoLyte generic MMP substrate to determine MMP activity. A significant decrease in μTBS after 6 months and 1 yr was observed for the control group only. No significant differences among groups were shown at 24 h. After 6 months and 1 yr, the control group demonstrated significantly lower μTBS than all treatment groups. Both 0.5% and 1.0%, BAC applied for 60 s inhibited total MMP activity by 31% and 54%, respectively. Both BAC and MBAC contributed to the preservation of resin-dentin bonds likely due to its inhibitory properties of endogenous dentin proteinases. PMID:25639285

  18. Functionalization of poly(methyl methacrylate) (PMMA) as a substrate for DNA microarrays

    PubMed Central

    Fixe, F.; Dufva, M.; Telleman, P.; Christensen, C. B. V.

    2004-01-01

    A chemical procedure was developed to functionalize poly(methyl methacrylate) (PMMA) substrates. PMMA is reacted with hexamethylene diamine to yield an aminated surface for immobilizing DNA in microarrays. The density of primary NH2 groups was 0.29 nmol/cm2. The availability of these primary amines was confirmed by the immobilization of DNA probes and hybridization with a complementary DNA strand. The hybridization signal and the hybridization efficiency of the chemically aminated PMMA slides were comparable to the hybridization signal and the hybridization efficiency obtained from differently chemically modified PMMA slides, silanized glass, commercial silylated glass and commercial plastic Euray™ slides. Immobilized and hybridized densities of 10 and 0.75 pmol/cm2, respectively, were observed for microarrays on chemically aminated PMMA. The immobilized probes were heat stable since the hybridization performance of microarrays subjected to 20 PCR heat cycles was only reduced by 4%. In conclusion, this new strategy to modify PMMA provides a robust procedure to immobilize DNA, which is a very useful substrate for fabricating single use diagnostics devices with integrated functions, like sample preparation, treatment and detection using microfabrication and microelectronic techniques. PMID:14718554

  19. Functionalization of poly(methyl methacrylate) (PMMA) as a substrate for DNA microarrays.

    PubMed

    Fixe, F; Dufva, M; Telleman, P; Christensen, C B V

    2004-01-01

    A chemical procedure was developed to functionalize poly(methyl methacrylate) (PMMA) substrates. PMMA is reacted with hexamethylene diamine to yield an aminated surface for immobilizing DNA in microarrays. The density of primary NH2 groups was 0.29 nmol/cm2. The availability of these primary amines was confirmed by the immobilization of DNA probes and hybridization with a complementary DNA strand. The hybridization signal and the hybridization efficiency of the chemically aminated PMMA slides were comparable to the hybridization signal and the hybridization efficiency obtained from differently chemically modified PMMA slides, silanized glass, commercial silylated glass and commercial plastic Euray trade mark slides. Immobilized and hybridized densities of 10 and 0.75 pmol/cm2, respectively, were observed for microarrays on chemically aminated PMMA. The immobilized probes were heat stable since the hybridization performance of microarrays subjected to 20 PCR heat cycles was only reduced by 4%. In conclusion, this new strategy to modify PMMA provides a robust procedure to immobilize DNA, which is a very useful substrate for fabricating single use diagnostics devices with integrated functions, like sample preparation, treatment and detection using microfabrication and microelectronic techniques. PMID:14718554

  20. Hydrogen peroxide filled poly(methyl methacrylate) microcapsules: potential oxygen delivery materials.

    PubMed

    Mallepally, Rajendar R; Parrish, Chance C; Mc Hugh, Mark A M; Ward, Kevin R

    2014-11-20

    This paper describes the synthesis of H₂O₂-H₂O filled poly(methyl methacrylate) (PMMA) microcapsules as potential candidates for controlled O₂ delivery. The microcapsules are prepared by a water-in-oil solvent emulsion and evaporation method. The results of this study describe the effect of process parameters on the characteristics of the microcapsules and on their in vitro performance. The size of the microcapsules, as determined from scanning electron microscopy, ranges from ∼5 to 30 μm and the size distribution is narrow. The microcapsules exhibit an internal morphology with entrapped H₂O₂-H₂O droplets randomly distributed in the PMMA continuous phase. In vitro release studies of 4.5 wt% H₂O₂-loaded microcapsules show that ∼70% of the H₂O₂ releases in 24h. This corresponds to a total O₂ production of ∼12 cc/gram of dry microcapsules. Shelf-life studies show that the microcapsules retain ∼84 wt% of the initially loaded H₂O₂ after nine months storage at 2-8 °C, which is an attractive feature for clinical applications.

  1. Dual responsive pickering emulsion stabilized by poly[2-(dimethylamino)ethyl methacrylate] grafted cellulose nanocrystals.

    PubMed

    Tang, Juntao; Lee, Micky Fu Xiang; Zhang, Wei; Zhao, Boxin; Berry, Richard M; Tam, Kam C

    2014-08-11

    A weak polyelectrolyte, poly[2-(dimethylamino)ethyl methacrylate] (PDMAEMA), was grafted onto the surface of cellulose nanocrystals via free radical polymerization. The resultant suspension of PDMAEMA-grafted-cellulose nanocrystals (PDMAEMA-g-CNC) possessed pH-responsive properties. The grafting was confirmed by FTIR, potentiometric titration, elementary analysis, and thermogravimetric analysis (TGA); the surface and interfacial properties of the modified particles were characterized by surface tensiometer. Compared to pristine cellulose nanocrystals, modified CNC significantly reduced the surface and interfacial tensions. Stable heptane-in-water and toluene-in-water emulsions were prepared with PDMAEMA-g-CNC. Various factors, such as polarity of solvents, concentration of particles, electrolytes, and pH, on the properties of the emulsions were investigated. Using Nile Red as a florescence probe, the stability of the emulsions as a function of pH and temperature was elucidated. It was deduced that PDMAEMA chains promoted the stability of emulsion droplets and their chain conformation varied with pH and temperature to trigger the emulsification and demulsification of oil droplets. Interestingly, for heptane system, the macroscopic colors varied depending on the pH condition, while the color of the toluene system remained the same. Reversible emulsion systems that responded to pH were observed and a thermoresponsive Pickering emulsion system was demonstrated. PMID:24983405

  2. Pulse laser-induced particle separation from polymethyl methacrylate: a mechanistic study

    NASA Astrophysics Data System (ADS)

    Arif, S.; Armbruster, O.; Kautek, W.

    2013-04-01

    The separation mechanism of opaque and transparent model micro-particles, graphite and polystyrene copolymer spheres, respectively, from polymethyl methacrylate (PMMA) substrates were investigated employing a ns-pulse laser radiating at 532 nm. The particles transparent in the visible wavelength range could be removed from PMMA efficiently in a very narrow fluence range between 1 and 2 J/cm2 according to a simple 1D thermal expansion model. Above this fluence region, with single pulses, the transparent microspheres caused local ablation of the PMMA substrate in the optical microlens nearfield. This process led to removal of the particles themselves due to the expansion of the ablation plasma. The irregularly shaped graphite particles shaded the underlying substrate from the incoming radiation so that no optical nearfield damage mechanism could be observed. Therefore, a substantial cleaning window between 0.5 and more than 16 J/cm2 was provided. The graphite data suggest an ablation mechanism of the particulates themselves due to a high optical absorption coefficient.

  3. Aging of adhesive interfaces treated with benzalkonium chloride and benzalkonium methacrylate.

    PubMed

    Sabatini, Camila; Pashley, David H

    2015-04-01

    Inhibition of endogenous dentin matrix metalloproteinases (MMPs) within incompletely infiltrated hybrid layers can contribute to the preservation of resin-dentin bonds. This study evaluated the bond stability of interfaces treated with benzalkonium chloride (BAC) and benzalkonium methacrylate (MBAC), and the inhibitory properties of these compounds on dentin MMP activity. Single-component adhesive ALL-BOND UNIVERSAL, modified with BAC or MBAC at concentrations of 0, 0.5, 1.0, and 2.0%, was used for microtensile bond strength (μTBS) evaluation after 24 h, 6 months, and 1 yr. Beams produced from human dentin were treated with 37% phosphoric acid, dipped in 0.5% BAC, 1.0% BAC, or water (control) for 60 s, and then incubated in SensoLyte generic MMP substrate to determine MMP activity. A significant decrease in the μTBS after 6 months and 1 yr was observed for the control group only. No significant differences among groups were shown at 24 h. After 6 months and 1 yr, the control group demonstrated significantly lower μTBS than all treatment groups. When applied for 60 s, 0.5% BAC inhibited total MMP activity by 31%, and 1.0% BAC inhibited total MMP activity by 54%. Both BAC and MBAC contributed to the preservation of resin-dentin bonds, probably because of their inhibitory properties of endogenous dentin proteinases.

  4. Invivo absorption behaviour of theophylline from starch-methyl methacrylate matrix tablets in beagle dogs.

    PubMed

    Fernández-Campos, F; Ferrero, C; Colom, H; Jiménez-Castellanos, M R

    2015-01-30

    This study evaluates in vivo the drug absorption profiles from potato starch-methyl methacrylate matrices(*) using theophylline as a model drug. Healthy beagle dogs under fasting conditions were used for in vivo studies and plasma samples were analyzed by a fluorescence polarization immunoassay analysis (FPIA method). Non-compartmental and compartmental (population approach) analysis was performed to determine the pharmacokinetic parameters. The principle of superposition was applied to predict multiple dose plasma concentrations from experimental single dose data. An in vitro-in vivo correlation (IVIVC) was also assessed. The sustained absorption kinetics of theophylline from these formulations was demonstrated by comparison with two commercially available oral sustained-release theophylline products (Theo-Dur(®) and Theolair(®)). A one-compartment model with first order kinetics without lag-time best describes the absorption/disposition of theophylline from the formulations. Results revealed a theophylline absorption rate in the order FD-HSMMA≥Theo-Dur(®)≥OD-CSMMA>Theolair(®)≥FD-CSMMA. On the basis of simulated plasma theophylline levels, a twice daily dosage (every 12h) with the FD-CSMMA tablets should be recommended. A Level C IVIVC was found between the in vitrot50% and the in vivo AUC/D, although further optimization of the in vitro dissolution test would be needed to adequately correlate with in vivo data.

  5. Low-temperature polymerization of methyl methacrylate emulsion gels through surfactant catalysis.

    PubMed

    Zhang, Tan; Xu, Gu; Regev, Oren; Blum, Frank D

    2016-01-01

    Poly(methyl methacrylate) (PMMA)/silica/cetyltrimethylammonium bromide (CTAB) composites were prepared through surfactant catalyzed free radical polymerizations at 40 °C. Fumed silica particles controlled the morphology of the polymeric composites producing porous structures. The internal structures of the porous composite were determined using temperature-modulated differential scanning calorimetry (TMDSC). The fumed silica particles were encapsulated by an incompletely covered CTAB monolayer, with a crystallization temperature, T(C,CTAB)=76 °C, and a mixed PMMA/CTAB shell, with T(C,CTAB)=63 °C. The fumed silica surfaces acted as inhibitors for PMMA free radical polymerizations. Much of the PMMA formed in the composites was adsorbed on the silica, as evidenced by its elevated glass transition temperature compared to bulk. The enhanced decomposition of the initiator was catalyzed by CTAB and resulted in free radical polymerization of PMMA at 40 °C, which is considerably lower than the temperatures normally used for PMMA synthesis by free radical means with thermal initiation. These lowered polymerization temperatures allow energy efficient production of composites, which can incorporate temperature sensitive materials. PMID:26397919

  6. A hematoxylin and eosin-like stain for glycol methacrylate embedded tissue sections.

    PubMed

    Troyer, H; Babich, E

    1981-01-01

    A staining procedure is described for use with glycol methacrylate embedded tissue sections which does not stain the plastic embedment or remove the sections from the glass slides. The basic dye is celestine blue B. It is prepared by treating 1 g of the dye with 0.5 ml concentrated sulfuric acid. It is then dissolved with the following solution. Add 14 ml glycerine to 100 ml 2.5% ferric ammonium sulfate and warm the solution to 50 C. Finally adjust the pH to 0.8 to 0.9 The acid staining solution consists of 0.075% ponceau de xylidine and 0.025% acid fuchsin in 10% acetic acid. Slides containing the dried plastic sections are immersed in the celestine blue solution for five minutes and in the ponceau-fuchsin solution for ten minutes with an intervening water rinse. After a final wash, the sections are air dried and coverslipped. This staining procedure colors the tissues nearly the same as hematoxylin and eosin procedures.

  7. Study of plasma-induced graft polymerization of stearyl methacrylate on cotton fabric substrates

    NASA Astrophysics Data System (ADS)

    Li, Yongqiang; Zhang, Yan; Zou, Chao; Shao, Jianzhong

    2015-12-01

    A simple and facile method to prepare the cotton fabric with hydrophobicity was described in the present work. In the one-step process, the cotton fabric pre-impregnated with the monomer solution of stearyl methacrylate (SMA) was placed in the plasma chamber and followed by glow discharge of the Helium low temperature plasma. The cotton fabrics before and after the plasma treatment were characterized by field emission scanning electron microscopy (FESEM), infrared spectroscopic analysis (FTIR), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA), respectively. The wettability of the cotton fabrics was evaluated by contact angle measurement. Fabric Hand Values and mechanical properties were also measured in the experiment. The results showed that polymer films could be coated on the cotton fibers through the plasma induced grafting polymerization of SMA. The modified cotton fabrics exhibited an extraordinary hydrophobicity with a contact angle of 149° for a 5 μL water droplet and excellent thermal stability. The relative hand value and mechanical breaking strength of the cotton fabrics declined slightly after graft polymerization of SMA by the plasma.

  8. Improved performance of α-amylase immobilized on poly(glycidyl methacrylate-co-ethylenedimethacrylate) beads.

    PubMed

    He, Tian; Tian, Yong-Le; Qi, Liang; Zhang, Jing; Zhang, Zhi-Qi

    2014-04-01

    α-Amylase was successfully immobilized onto poly(glycidyl methacrylate-co-ethylenedimethacrylate) (PGMA/EDMA) beads with high immobilization efficiency of 87.8%. PGMA/EDMA beads with a relatively uniform diameter of 2-3 μm were prepared by single-step swelling polymerization. After amination with ethanediamine and activation with glutaraldehyde, PGMA/EDMA beads showed commendable α-amylase immobilization capacity of 35.1 mg g(-1) carrier. Compared with free form, immobilized α-amylase had increasement of 12.94 mg mL(-1) for Km and 0.124 mmol mL(-1) min(-1) for Vmax, improved acid resistance (the optimal pH from 7 to 5), presented better thermal stability by retaining 61% activity than 40% at 90 °C, and displayed high operational reusability by retaining 58% of its initial activity after nine uses. Moreover, less than 10% of the free enzyme and more than 80% of the immobilized enzyme retained activity after 180 min pre-incubation at 50 °C. The easy modification, high immobilization efficiency and good properties of immobilized α-amylase in the present study indicate that PGMA/EDMA beads are suitable for α-amylase immobilization. The enhancement of acid resistance and thermo stability is doubtless of benefit for the industrial use of α-amylase.

  9. Antioxidant Properties of 2-Hydroxyethyl Methacrylate-Based Copolymers with Incorporated Sterically Hindered Amine.

    PubMed

    Poláková, L; Raus, V; Kostka, L; Braunová, A; Pilař, J; Lobaz, V; Pánek, J; Sedláková, Z

    2015-09-14

    A series of model linear copolymers of 2-hydroxyethyl methacrylate (HEMA) and a sterically hindered amine derivative [N-(2,2,6,6-tetramethyl-piperidin-4-yl)methacrylamide (HAS)] were synthesized and characterized. Scavenging activities of the copolymers against reactive oxygen species (peroxyl and hydroxyl radicals) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals were determined. It was found that copolymers with medium HAS content (3.5-4.0 mol %) were better scavengers than copolymers with lower and higher HAS content and also than polyHEMA and polyHAS homopolymers and the HAS monomer. Importantly, these copolymers compared favorably even to established low-molecular weight antioxidant standards (BHA and dexpanthenol). Monomer reactivity ratios were determined, and the microstructure of the copolymers was assessed. Subsequently, cross-linked copolymers in the powder and film forms with optimal HAS content were synthesized. Their scavenging activities against the three types of radicals were determined, revealing that these hydrogels are potent scavengers of reactive oxygen species. PMID:26258477

  10. Synthesis of antibacterial methacrylate monomer derived from thiazole and its application in dental resin.

    PubMed

    Luo, Weixun; Huang, Qiting; Liu, Fang; Lin, Zhengmei; He, Jingwei

    2015-09-01

    A non-quaternary ammonium antibacterial methacrylate monomer MEMT derived from thiazole was synthesized and applied into UDMA/TEGDMA dental resin with a series of mass fraction (10 wt%, 20 wt%, and 30 wt%). Double bond conversion, polymerization shrinkage, water sorption, solubility, flexural strength and modulus, and antibacterial activity of MEMT containing resin formulations were investigated with UDMA/TEGDMA as control resin. The results showed that MEMT containing dental resin had higher double bond conversion than control resin. Compared with control polymer, all MEMT containing polymer had comparable or lower polymerization shrinkage, water sorption and solubility, except for the polymer with 30 wt% of MEMT which had higher water sorption and solubility than control polymer. The MEMT had no influence on flexural strength and modulus before water immersion, but all MEMT containing polymers had lower flexural strength and modulus than control polymer after water immersion. The MEMT could endow dental polymer with obvious antibacterial activity by immobilizing MEMT into the polymeric network.

  11. Fundamental study on dissolution behavior of poly(methyl methacrylate) by quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Konda, Akihiro; Yamamoto, Hiroki; Yoshitake, Shusuke; Kozawa, Takahiro

    2016-03-01

    Ionizing radiations such as extreme ultraviolet (EUV) and electron beam (EB) are the most promising exposure source for next-generation lithographic technology. In the realization of high resolution lithography, it is necessary for resist materials to improve the trade-off relationship among sensitivity, resolution, and line width roughness (LWR). In order to overcome them, it is essential to understand basic chemistry of resist matrices in resist processes. In particular, the dissolution process of resist materials is a key process. Therefore, it is essential for next-generation resist design for ionizing radiation to clarify the dissolution behavior of the resist film into developer. However, the details in dissolution process of EUV and EB resist films have not been investigated thus far. In this study, main chain scission and dissolution behavior of poly(methyl methacrylate) (PMMA) as main chain scission type resist was investigated using quartz crystal microbalance (QCM) method and gel permeation chromatography (GPC) in order to understand the relationship between the degree of PMMA degradation and dissolution behavior. The relationship between the molecular weight after irradiation and the swelling behavior was clarified.

  12. Cytotoxicity and cytokine expression induced by silorane and methacrylate-based composite resins

    PubMed Central

    LONGO, Daniele Lucca; PAULA-SILVA, Francisco Wanderley Garcia; FACCIOLI, Lucia Helena; GATÓN-HERNÁNDEZ, Patrícia Maria; de QUEIROZ, Alexandra Mussolino; da SILVA, Léa Assed Bezerra

    2016-01-01

    ABSTRACT The successful use of composite resins in Dentistry depends on physicochemical properties, but also on the biological compatibility of resins, because of the close association between pulp and dentin. Objective The aim of this study was to evaluate cytotoxicity and cytokine production induced by light-cured or non-light-cured methacrylate-based and silorane composite resins in RAW 264.7 macrophages. Material and Methods Cells were stimulated with the extracts from light-cured or non-light-cured composite resins. After incubation for 24 h, cytotoxicity was assessed with the lactate dehydrogenase (LDH) and methyl thiazolyl tetrazolium (MTT) assays, and total protein was quantified using the Lowry method. TNF-α detection was examined with an enzyme-linked immunosorbent assay (ELISA) conducted with cell supernatants after cell stimulation for 6, 12, and 24 h. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s post hoc test (α=0.05). Results KaloreTM and FiltekTM Silorane were cytotoxic with or without light curing (p<0.05) after 24 h of incubation. KaloreTM stimulated the early production of TNF-α in comparison with control (p<0.05), whereas FiltekTM Silorane did not affect TNF-α levels after 6 and 12 h (p>0.05). However, after 24 h FiltekTM Silorane inhibited the production of TNF-α (p<0.05). Conclusions KaloreTM and FiltekTM Silorane were cytotoxic regardless of light curing. The extract obtained from KaloreTM after 15 days of incubation stimulated the production of TNF-α, unlike that obtained from FiltekTM Silorane. PMID:27556204

  13. Electrospun zwitterionic poly(sulfobetaine methacrylate) for nonadherent, superabsorbent, and antimicrobial wound dressing applications.

    PubMed

    Lalani, Reza; Liu, Lingyun

    2012-06-11

    Zwitterionic poly(sulfobetaine methacrylate) (PSBMA) has been well studied for its superhydrophilic and ultralow biofouling properties, making it a promising material for superabsorbent and nonadherent wound dressings. Electrospinning provides multiple desirable features for wound dressings, including high absorptivity due to high surface-area-to-volume ratio, high gas permeation, and conformability to contour of the wound bed. The goal of this work is to develop a fibrous membrane of PSBMA via electrospinning and evaluate its properties related to wound dressing applications. Being superhydrophilic, PSBMA fibers fabricated by a conventional electrospinning method would readily dissolve in water, whereas if cross-linker is added, the formation of hydrogel would prevent electrospinning. A three-step polymerization-electrospinning-photo-cross-linking process was developed in this work to fabricate the cross-linked electrospun PSBMA fibrous membrane. Such electrospun membrane was stable in water and exhibited high water absorption of 353% (w/w), whereas the PSBMA hydrogel only absorbed 81% water. The electrospun membrane showed strong resistance to protein adsorption and cell attachment. Bacterial adhesion studies using Gram negative P. aeruginosa and Gram positive S. epidermidis showed that the PSBMA electrospun membrane was also highly resistant to bacterial adhesion. The Ag(+)-impregnated electrospun PSBMA membrane was shown microbicidal, against both S. epidermidis and P. aeruginosa. Such electrospun PSBMA membrane is ideal for a novel type of nonadherent, superabsorbent, and antimicrobial wound dressing. The superior water absorption aids in fluid removal from highly exudating wounds while keeping the wound hydrated to support healing. Because of the resistance to protein, cell, and bacterial adhesion, the dressing removal will neither cause patients' pain nor disturb the newly formed tissues. The dressing also prevents the attachment of environmental bacteria

  14. Evaluation of porous networks of poly(2-hydroxyethyl methacrylate) as interfacial drug delivery devices.

    PubMed

    Dziubla, T D; Torjman, M C; Joseph, J I; Murphy-Tatum, M; Lowman, A M

    2001-11-01

    Long-term implantable drug delivery devices are desirable to achieve rapid and reliable delivery of bioactive substances to the body. The limitation of most implantable devices is the resulting chronic inflammatory response and fibrous encapsulation of the implant, which prevents effective drug delivery for prolonged periods. One method of overcoming this problem is the addition of an intermediary that could prevent capsule formation. Biocompatible materials with interconnected pore structures greater than 8-10 microm have been shown to support the ingrowth and maintenance of vascularized tissue. In this investigation, we evaluate the efficacy of using porous hydrogel sponges for the tissue interface in an implantable drug delivery device. Porous networks of poly(2-hydroxyethyl methacrylate) (PHEMA) were synthesized using a thermally initiated free-radical solution polymerization. To characterize the microstructure of the PHEMA networks, scanning electron microscopy and mercury porosimetry were used. By altering the solvent fraction in the reaction mixture, PHEMA sponges were synthesized with interconnected pores ranging in size from from 6 to 15 microm with porosities of 55% to 87%. Following the in vitro evaluation, sponges were attached to the distal end of a 20-gauge catheter tubing, and implanted subcutaneously and intraperitoneally. After 5 months implantation, insulin was infused into the devices from external pumps and rapid insulin absorption was observed in conjunction with dramatic lowering of blood glucose levels. From histological evaluation of explanted devices, we observed highly vascularized tissue surrounding the mesenteric implants. These results indicate that it may be possible to use PHEMA sponges for a tissue intermediary for long-term implantable drug delivery devices. PMID:11561895

  15. Transdermal gelation of methacrylated macromers with near-infrared light and gold nanorods.

    PubMed

    Gramlich, William M; Holloway, Julianne L; Rai, Reena; Burdick, Jason A

    2014-01-10

    Injectable hydrogels provide locally controlled tissue bulking and a means to deliver drugs and cells to the body. The formation of hydrogels in vivo may involve the delivery of two solutions that spontaneously crosslink when mixed, with pH or temperature changes, or with light (e.g., visible or ultraviolet). With these approaches, control over the kinetics of gelation, introduction of the initiation trigger (e.g., limited penetration of ultraviolet light through tissues), or alteration of the material physical properties (e.g., mechanics) may be difficult to achieve. To overcome these limitations, we used the interaction of near-infrared (NIR) light with gold nanorods (AuNRs) to generate heat through the photothermal effect. NIR light penetrates tissues to a greater extent than other wavelengths and provides a means to indirectly initiate radical polymerization. Specifically, this heating coupled with a thermal initiator (VA-044) produced radicals that polymerized methacrylated hyaluronic acid (MeHA) and generated hydrogels. A range of VA-044 concentrations changed the gelation time, yielding a system stable at 37 ° C for 22 min that gels quickly (~3 min) when heated to 55 ° C. With a constant irradiation time (10 min) and laser power (0.3 W), different VA-044 and AuNR concentrations tuned the compressive modulus of the hydrogel. By changing the NIR irradiation time we attained a wide range of moduli at a set solution composition. In vivo mouse studies confirmed that NIR laser irradiation through tissue could gel an injected precursor solution transdermally.

  16. Design and characterization of an adhesive matrix based on a poly(ethyl acrylate, methyl methacrylate).

    PubMed

    Cilurzo, Francesco; Minghetti, Paola; Pagani, Stefania; Casiraghi, Antonella; Montanari, Luisa

    2008-01-01

    The main issue in the development of transdermal patches made of poly(ethyl acrylate, methyl methacrylate) (Eudragit NE 40D, PMM) is the shrinkage phenomenon during the spreading of the latex onto the release liner. To solve this problem, the latex is usually freeze-dried and then re-dissolved in an organic solvent (method 1). To simplify the production process, we prepared an adhesive matrix by adding to the commercial PMM latex a plasticizer and an additive (anti-shrinkage agent) that avoids the shrinkage of the water dispersion spread onto the release liner (method 2). In some cases the active ingredient itself, such as potassium diclofenac (DK) and nicotine (NT), works as anti-shrinkage agent. In this work, the effects of the preparation method, types and concentrations of the plasticizer (triacetin and tributyl citrate) on the adhesive properties of the transdermal patches were investigated. The adhesive properties of the prepared patch were determined by texture analysis, peel adhesion test and shear adhesion. The PMM/plasticizer interactions were evaluated by ATR-FTIR spectroscopy. Furthermore, the in vitro skin permeation profiles of DK and NT released from the patch were determined by Franz cell method. Generally speaking, the variables that mainly modify the adhesive properties are the concentration and type of the plasticizer. The skin permeation profiles of DK and NT from the patch prepared by method 2 overlapped with those obtained with the commercial products. The results underline that the PMM latex can be used conveniently in the development of transdermal patches. PMID:18563579

  17. Mechanistic study of secondary organic aerosol components formed from nucleophilic addition reactions of methacrylic acid epoxide

    NASA Astrophysics Data System (ADS)

    Birdsall, A. W.; Miner, C. R.; Mael, L. E.; Elrod, M. J.

    2014-08-01

    Recently, methacrylic acid epoxide (MAE) has been proposed as a precursor to an important class of isoprene-derived compounds found in secondary organic aerosol (SOA): 2-methylglyceric acid (2-MG) and a set of oligomers, nitric acid esters and sulfuric acid esters related to 2-MG. However, the specific chemical mechanisms by which MAE could form these compounds have not been previously studied. In order to determine the relevance of these processes to atmospheric aerosol, MAE and 2-MG have been synthesized and a series of bulk solution-phase experiments aimed at studying the reactivity of MAE using nuclear magnetic resonance (NMR) spectroscopy have been performed. The present results indicate that the acid-catalyzed MAE reaction is more than 600 times slower than a similar reaction of an important isoprene-derived epoxide, but is still expected to be kinetically feasible in the atmosphere on more acidic SOA. The specific mechanism by which MAE leads to oligomers was identified, and the reactions of MAE with a number of atmospherically relevant nucleophiles were also investigated. Because the nucleophilic strengths of water, sulfate, alcohols (including 2-MG), and acids (including MAE and 2-MG) in their reactions with MAE were found to be of a similar magnitude, it is expected that a diverse variety of MAE + nucleophile product species may be formed on ambient SOA. Thus, the results indicate that epoxide chain reaction oligomerization will be limited by the presence of high concentrations of non-epoxide nucleophiles (such as water); this finding is consistent with previous environmental chamber investigations of the relative humidity-dependence of 2-MG-derived oligomerization processes and suggests that extensive oligomerization may not be likely on ambient SOA because of other competitive MAE reaction mechanisms.

  18. Mechanistic study of secondary organic aerosol components formed from nucleophilic addition reactions of methacrylic acid epoxide

    NASA Astrophysics Data System (ADS)

    Birdsall, A. W.; Miner, C. R.; Mael, L. E.; Elrod, M. J.

    2014-12-01

    Recently, methacrylic acid epoxide (MAE) has been proposed as a precursor to an important class of isoprene-derived compounds found in secondary organic aerosol (SOA): 2-methylglyceric acid (2-MG) and a set of oligomers, nitric acid esters, and sulfuric acid esters related to 2-MG. However, the specific chemical mechanisms by which MAE could form these compounds have not been previously studied with experimental methods. In order to determine the relevance of these processes to atmospheric aerosol, MAE and 2-MG have been synthesized and a series of bulk solution-phase experiments aimed at studying the reactivity of MAE using nuclear magnetic resonance (NMR) spectroscopy have been performed. The present results indicate that the acid-catalyzed MAE reaction is more than 600 times slower than a similar reaction of an important isoprene-derived epoxide, but is still expected to be kinetically feasible in the atmosphere on more acidic SOA. The specific mechanism by which MAE leads to oligomers was identified, and the reactions of MAE with a number of atmospherically relevant nucleophiles were also investigated. Because the nucleophilic strengths of water, sulfate, alcohols (including 2-MG), and acids (including MAE and 2-MG) in their reactions with MAE were found to be of similar magnitudes, it is expected that a diverse variety of MAE + nucleophile product species may be formed on ambient SOA. Thus, the results indicate that epoxide chain reaction oligomerization will be limited by the presence of high concentrations of non-epoxide nucleophiles (such as water); this finding is consistent with previous environmental chamber investigations of the relative humidity dependence of 2-MG-derived oligomerization processes and suggests that extensive oligomerization may not be likely on ambient SOA because of other competitive MAE reaction mechanisms.

  19. Effect of Staining Solutions on Color Stability of Silorane & Methacrylate Restorative Material

    PubMed Central

    S. Madhyastha, Prashanthi; G. Naik, Dilip; Kotian, Ravindra; Srikant, N.; M. R. Bhat, Kumar

    2015-01-01

    Color stability throughout the functional lifetime of restorations is important for the durability of treatment and of cosmetic importance. The purpose of this study was to evaluate the discoloration properties of a silorane-based (Filtek P90) and methacrylate-based (Z100) composites upon exposure to different staining solutions that are used on day to day basis (turmeric, tea, coffee, cocoa, lime, yoghurt and distilled water) for different immersion periods (1, 7, 14 and 28 days). The colors of all specimens before and after storage in the solutions were measured by a reflectance spectrophotometer based on CIE Lab system and the color differences were calculated. Data were statistically analyzed by repeated measures of ANOVA and sidak post hoc test (for immersion period);‘t’ test (for each material) and one way ANOVA (for staining agents). All the staining agents showed significant difference in staining over time in both the materials. However, Z100 showed higher quantum of discoloration at all time periods at each staining agents (p<0.005). In conclusion, the silorane-based resin (Filtek P90) composites exhibited better color stability (less change in ΔE) after exposure to the staining solutions. Among the staining agents cocoa was found to be least staining followed by lime, yoghurt, coffee, tea whereas turmeric discolored the composites to the maximum. Highest discoloration was seen at day 28 in all staining agents. Cocoa and lime discolored to maximum at early stages but remained stable thereafter whereas tea, coffee and turmeric progressively discolored the composite over time.

  20. Polystyrene-divinylbenzene-glycidyl methacrylate stationary phase grafted with poly (amidoamine) dendrimers for ion chromatography.

    PubMed

    Guo, Dandan; Lou, Chaoyan; Zhang, Peimin; Zhang, Jiajie; Wang, Nani; Wu, Shuchao; Zhu, Yan

    2016-07-22

    In this work, a novel ion exchange stationary phase based on different generations of poly (amidoamine) dendrimers (PAMAM) was developed for the determination of inorganic anions and carbohydrates. Synthesis of the PAMAM was carried out with the polymerization reaction of ethylenediamine and methyl acrylate. The synthesized PAMAM was then grafted to the polystyrene-divinylbenzene-glycidyl methacrylate (PS-GMA) to form PAMAM-based beads. These beads were finally modified with 1,4-butanediol diglycidyl ether (BDDE) to generate the anion exchanger, which were characterized by scanning electron microscopy (SEM), brunauer-emmett-teller (BET), fourier transform infrared spectroscopy (FTIR), and elemental analysis. Elemental analysis, breakthrough curves and capacity factors showed that more epoxy groups and higher PAMAM generations in stationary phase could result in higher anion exchange capacity. The efficiency, durability and stability of the proposed anion exchanger were investigated by using six inorganic anions (fluoride, chloride, nitrite, bromide, nitrate and sulfate) and four carbohydrates (trehalose, glucose, maltotriose and galacturonic acid) as analytes, respectively. The reliability of the proposed ion chromatographic stationary phase was demonstrated by determining the content of galacturonic acid in polysaccharides from Poria cocos and Atractylodes macrocephala. The relative standard deviations of retention time, peak height, and peak area for galacturonic acid were 0.39%, 1.22%, and 2.02%, respectively. The spiked recoveries were in the range of 88.29%-100.51% for plant polysaccharides. Due to the good structural homogeneity, intense internal porosity, biological compatibility and high density of active groups in PAMAM, this grafted stationary phase showed good ion-exchange characteristics, especially in biological charged molecules.