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Hydroxyethyl Methacrylate (hydroxyethyl + methacrylate)
Selected AbstractsPlasma-induced grafting of hydroxyethyl methacrylate (HEMA) onto chitosan membranes by a swelling methodPOLYMER INTERNATIONAL, Issue 2 2003Yeping Li Abstract Hydroxyethyl methacrylate (HEMA) was grafted onto chitosan membranes by plasma-graft polymerization. Effects of monomer concentration, plasma power and plasma time on the amount of grafting were investigated. The results showed that there were two processes: grafting polymerization and etching of the membrane. The surface of the grafted membrane was evaluated by FTIR. Scanning electron microscopy indicated that the surface morphology of the grafted membrane could be adjusted through plasma power. Water contact angles of the chitosan surface decreased from 78.2° to 45.4° while the amount of grafting increased from 0 to 12.2%, indicating improved hydrophilicity of the membrane surface. Permeation coefficients through the original membrane, the membrane treated at 55,W for 15,min, and the membrane treated at 55,W for 30,min for creatinine were 9.12,×,10,7, 10.6,×,10,7 and 8.57,×,10,7,cm2,s,1, respectively. Thermogravimetry and mechanical testing showed that there were no significant changes on the bulk property of chitosan membrane after modification. © 2003 Society of Chemical Industry [source] Surface-Grafted Gel-Brush/Metal Nanoparticle HybridsADVANCED FUNCTIONAL MATERIALS, Issue 6 2010Edmondo M. Benetti Abstract Polymer brushes are classically defined and are to date employed as assemblies of macromolecules tethered at one end to a surface. The concept of preparing surface-grafted gels by crosslinking such brushes is attractive since it gives rise to new opportunities related to the constraints present in this type of structure. Aiming at the development of nanostructured films possessing precisely adjustable chemical, mechanical, and optical properties, the present article describes the preparation of novel grafted layers based on gel-brush/metal nanoparticle hybrids. These films were synthesized by surface-initiated atom transfer radical polymerization of hydroxyethyl methacrylate with a small percentage of a crosslinker. The swelling, morphological, and mechanical properties of the gel-brushes are shown to be highly dependent on the relative amount of crosslinker used. The gel-brushes are subsequently used as matrixes for the controlled synthesis of silver nanoparticles with overall characteristics that are specifically tunable as a function of the macromolecular structure of the brush template. [source] Synthesis and rheological characterization of graft copolymers of butyl and hydroxyethyl methacrylates on starchesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Mariló Gurruchaga Abstract To study the possibility of using some acrylic-grafted polysaccharides as matrix tablets, graft copolymers of butyl methacrylate and hydroxyethyl methacrylate on starch and on hydroxypropyl starch were synthesized. In this work, the effects of the different chemical compositions of the various synthesized graft copolymers on the hydrophilicity and rheological characteristics were examined. Water absorption values that ranged from 5 to 45% were obtained. Rheological testing determined with dispersions (5% w/w) in water showed that the graft copolymers formed weak gels of high viscosity. Moreover, the synthesized powders showed good flow and good compaction. These measurements pointed toward the possibility of their application for drug release. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] Chitosan-grafted poly(hydroxyethyl methacrylate- co -glycidyl methacrylate) membranes for reversible enzyme immobilizationJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2007M. Yakup Ar Abstract Epoxy group-containing poly(hydroxyethyl methacrylate/glycidyl methacrylate), p(HEMA/GMA), membrane was prepared by UV initiated photopolymerization. The membrane was grafted with chitosan (CH) and some of them were chelated with Fe(III) ions. The CH grafted, p(HEMA/GMA), and Fe(III) ions incorporated p(HEMA/GMA)-CH-Fe(III) membranes were used for glucose oxidase (GOD) immobilization via adsorption. The maximum enzyme immobilization capacity of the p(HEMA/GMA)-CH and p(HEMA/GMA)-CH-Fe(III) membranes were 0.89 and 1.36 mg/mL, respectively. The optimal pH value for the immobilized GOD preparations is found to have shifted 0.5 units to more acidic pH 5.0. Optimum temperature for both immobilized preparations was 10°C higher than that of the free enzyme and was significantly broader at higher temperatures. The apparent Km values were found to be 6.9 and 5.8 mM for the adsorbed GOD on p(HEMA/GMA)-CH and p(HEMA/GMA)-CH-Fe(III) membranes, respectively. In addition, all the membranes surfaces were characterized by contact angle measurements. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3084,3093, 2007 [source] Preparation and characterization of infection-resistant antibiotics-releasing hydrogels rods of poly[hydroxyethyl methacrylate- co -(poly(ethylene glycol)-methacrylate]: Biomedical application in a novel rabbit penile prosthesis modelJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2008M. Yakup Ar Abstract In this work, preparation and characterization of novel three different antibiotic loaded penile prosthesis in the rod form were investigated by copolymerization of 2-hydroxyethylmethacrylate (HEMA) with poly(ethylene glycol)-methacrylate, (PEG-MA). To achieve this goal, a series of novel copolymer hydrogels were prepared in rod form using HEMA and PEG-MA monomers via UV initiated photopolymerization. The thermal stability of the copolymer was found to be lowered by increase in the ratio of PEG-MA in the rod structure. Contact angle measurements on the surface of copolymer hydrogel demonstrated that the copolymer gave rise to a significant hydrophilic surface compared with pure poly(HEMA). The blood protein adsorption and platelet adhesion were significantly reduced on the surface of the copolymer hydrogels compared with control pure poly(HEMA). Poly(HEMA:PEG-MA;1:1)-1 formulation containing different antibiotics (20 mg antibiotic/g polymer) released about 90, 91, and 55% of the total loaded cephtriaxon, vancomycin, and gentamicin in 48 h at pH 7.4, respectively. Finally, antibiotics loaded biocompatible poly(HEMA:PEG-MA;1:1)-1 hydrogel compositions was used as a penile prosthesis in preventing cavernous tissue infections in a rabbit prosthesis model. The efficacy of the three different antibiotics loaded hydrogel system was evaluated in four different groups of rabbits, in which various infectious agents were inoculated. The animals were sacrificed after predetermined time periods, and clinical, histological and microbiological assessment on the implant side were carried out to detect infections. Eventually, we concluded that three different antibiotic loaded penile prostheses (i.e. poly(HEMA:PEG-MA;1:1)-1 hydrogel systems) were as effective as parenteral antibiotics applications. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] COVALENT IMMOBILIZATION OF INVERTASE ON CHEMICALLY ACTIVATED POLY (STYRENE-2-HYDROXYETHYL METHACRYLATE) MICROBEADSJOURNAL OF FOOD BIOCHEMISTRY, Issue 3 2008HAYDAR ALTINOK ABSTRACT A carrier for invertase enzyme was synthesized from styrene (S) and 2- hydroxyethyl methacrylate (HEMA) in the form of microbeads. These poly (styrene-2-hydroxyethyl methacrylate), P(S-HEMA) microbeads were activated by epichlorohydrin (ECH) treatment for covalent immobilization. The free and immobilized invertase were assayed in the hydrolysis of sucrose to glucose, and the obtained results were compared. The optimum pH was 4.5 for free and 5.5 for immobilized invertase. The optimum temperature of invertase shifted from 45C to 55C upon immobilization. For free and immobilized enzymes, kinetic parameters were calculated as 4.1 × 10,3 mol L,1and 9.2 × 10,3 mol L,1for Km, and 6.6 × 10,2 mol L,1 min,1and 4.1 × 10,1 mol L,1 min,1for Vmax, respectively. After 1 month of storage at 4C, free enzyme retained 36% of its initial activity, while for the ECH-activated P(S-HEMA) immobilized enzyme, P(S-HEMA)-E, this value was observed as 67%. In repeated batch use, i.e., 20 times in 3 days, 78% retention of the initial activity was observed for P(S-HEMA)-E system. PRACTICAL APPLICATIONS Immobilization of enzymes are very important for many industrial applications, e.g., food, medicine, pharmacology, etc. Invertase converts sucrose to glucose and fructose, which have wide applications in food industry especially as sweeteners. Glucose,fructose mixture has much lower crystallinity compared to sucrose and therefore used in the production of noncrystallizing jams and creams. They are also used as liquid sweeteners. Immobilization enables repeated use, provides significant reduction in the operation costs, facilitates easy separation and speeds up recovery of enzyme and extends the stability of enzyme by protecting the active material from deactivation. Industrial application of immobilized invertase may decrease the production cost of glucose,fructose mixture because it could be used repeatedly for long periods. Although invertase is not a very expensive enzyme, the technique can also be applied to expensive ones for biotechnological productions. [source] Plasma-induced grafting of hydroxyethyl methacrylate (HEMA) onto chitosan membranes by a swelling methodPOLYMER INTERNATIONAL, Issue 2 2003Yeping Li Abstract Hydroxyethyl methacrylate (HEMA) was grafted onto chitosan membranes by plasma-graft polymerization. Effects of monomer concentration, plasma power and plasma time on the amount of grafting were investigated. The results showed that there were two processes: grafting polymerization and etching of the membrane. The surface of the grafted membrane was evaluated by FTIR. Scanning electron microscopy indicated that the surface morphology of the grafted membrane could be adjusted through plasma power. Water contact angles of the chitosan surface decreased from 78.2° to 45.4° while the amount of grafting increased from 0 to 12.2%, indicating improved hydrophilicity of the membrane surface. Permeation coefficients through the original membrane, the membrane treated at 55,W for 15,min, and the membrane treated at 55,W for 30,min for creatinine were 9.12,×,10,7, 10.6,×,10,7 and 8.57,×,10,7,cm2,s,1, respectively. Thermogravimetry and mechanical testing showed that there were no significant changes on the bulk property of chitosan membrane after modification. © 2003 Society of Chemical Industry [source] Photopolymerization of alicyclic methacrylate hydrogels for controlled releasePOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2009Jing Han Abstract Alicyclic hydroxy methacrylate monomer, o -hydroxycyclohexyl methacrylate (HCMA), was synthesized and characterized by Fourier transformed infrared spectroscopy (FT-IR) and proton nuclear magnetic resonance spectroscopy (1H-NMR). Photopolymerization kinetics of HCMA was investigated via real-time infrared spectroscopy (RT-IR). Polymeric network hydrogels based on hydroxyethyl methacrylate (HEMA) and HCMA were prepared by using the photopolymerization technique. Mechanical strength, swelling characteristic, and controlled release behavior of hydrogels with various feed compositions were studied. Poly(HEMA-co-HCMA) hydrogel had higher storage modulus than that of poly(HEMA) hydrogel as investigated by dynamic mechanical analysis (DMA). Acid orange 8 was used as a model drug for the investigation of drug release behavior of copolymeric hydrogels. Results indicated that increase in HCMA ratio in hydrogel composition could reduce the swelling rate and prolong the release time. Scanning electron microscopy (SEM) was also utilized to study the surface morphology of hydrogels, and the results indicated that HCMA content influenced pore diameter on the hydrogel surface. Copyright © 2008 John Wiley & Sons, Ltd. [source] Effects of hydrophilic monomer types on poly(styrene-acrylate)/montmorillonite nanocomposites made by in-site emulsion polymerization,POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 6 2009Fa-Ai Zhang Abstract Organic modified montmorillonite (OMMT) was made of pristine montmorillonite (MMT) treated with cetyl trimethylammonium bromide (CTAB). Two kinds of nanocomposites, poly(styrene-acrylate)/MMT (P(S-A)/MMT) and poly (styrene-acrylate)/OMMT (P(S-A)/OMMT) were prepared from styrene (St), hydrophilic acrylate monomer, and MMT (or OMMT) by in-site emulsion polymerization. Effects of different monomers, , -hydroxyethyl methacrylate (HEMA), acrylic acid (AA), methacryclic acid (MAA) on the thermal stability of the two nanocomposites were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). The structures of the nanocomposites were characterized by infrared spectroscopy (IR) and X-ray diffraction (XRD). The morphology of the nanocomposite was observed by transmission electron microscope (TEM). The results showed that the thermal stabilities of the two composites were enhanced by the addition of HEMA, AA, or MAA. The P(S-A)/OMMT nanocomposite showed higher thermal stability than that of the P(S-A)/MMT nanocomposite. In particular, HEMA improved the thermal stability of the P(S-A)/OMMT nanocomposite, which is more efficient than methacrylic acid (MA) and AA. Copyright © 2009 John Wiley & Sons, Ltd. [source] Kinetics of acrylate emulsion polymerization containing hydrophilic hydroxyl monomer in the presence of nano-SiO2 particlesPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 3 2009Cai-Li Yu Abstract Kinetics of acrylate emulsion polymerization containing hydrophilic hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) in the presence of nano-SiO2 were investigated. The influence of temperature, emulsifier level, hydroxyl monomer content and the level of nano-SiO2 on monomer conversion, polymerization rate (Rp), and the particle size was studied. The results showed that the presence of nano-SiO2 increased the Rp when the level was below 5% but decreased when the level was above 7.5%, the more levels, the more seriously. As the temperature and emulsifier levels increased, and the presence of hydroxyl monomer, the Rp increased. The active energy of the system was 142.01,kJ/mol and the relationship of Rp and the concentration of emulsifier (E) was Rp,,,[E]0.38. The mean particle size increased, particle size distribution became broader as the nano-SiO2 levels increased. Copyright © 2008 John Wiley & Sons, Ltd. [source] Interaction of ,-gliadin with polyanions: Design considerations for sequestrants used in supportive treatment of celiac diseaseBIOPOLYMERS, Issue 5 2010Li Liang Abstract Copolymers of sodium 4-styrene sulfonate (SS) and hydroxyethyl methacrylate (HEMA) were investigated as sequestrants of ,-gliadin, a gluten protein, for the treatment of gluten intolerance. The interactions of ,-gliadin with poly(SS) and poly(HEMA- co -SS) with 9 and 26 mol% SS content were studied at gastric (1.2) and intestinal (6.8) pH using circular dichroism and measurements of turbidity, dynamic light scattering and zeta potential. The interactions and their influence on ,-gliadin secondary and aggregated structures depended mainly on the ratio of polymer negative and protein positive charges at pH 1.2, and on polymer SS content at polymer concentrations providing in excess of negative charges at either pH. Poly(SS) could not form complex particles with ,-gliadin in a sufficient excess of negative charges. Copolymerization with HEMA enhanced the formation of complex particles. Poly(HEMA- co -SS) with intermediate SS content was found to be the most effective sequestrant for ,-gliadin. This study provides insight into design considerations for polymer sequestrants used in the supportive treatment of celiac disease. © 2009 Wiley Periodicals, Inc. Biopolymers 93:418,428, 2010. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source] An antibiotic releasing contact lensACTA OPHTHALMOLOGICA, Issue 2009J CIOLINO Purpose To characterize a drug-eluting contact lens designed to release ciprofloxacin to the eye in a controlled manner for an extended period of time. Methods Thin fiilms, containing ciprofloxacin or fluorescein encapsulated in PLGA (Poly[lactic-co-glycolic acid]), were coating by pHEMA (poly[hydroxyethyl methacrylate]) by ultraviolet light polymerization, creating prototype contact lenses. The films were characterized by scanning electron microscopy. Release studies were conducted in phosphate buffered saline at 37°C with continuous shaking. Ciprofloxacin eluted from the contact lens was studied in an antimicrobial assay to verify antimicrobial effectiveness. Results Ciprofloxacin and fluorescein were released from the contact lenses in a controlled manner, demonstrating zero-order release kinetics under infinite sink conditions for over 4 weeks. The rate of drug release was controlled by modifying either the ratio of drug to PLGA or the molecular weight of the PLGA employed. Both the PLGA and the pHEMA affected release kinetics. Ciprofloxacin released from the contact lenses inhibited ciprofloxacin-sensitive Staphylococcus aureus at all time-points tested. Conclusion A thin drug-PLGA film coated with pHEMA could potentially be used to create contact lenses which can serve as a platform for ocular delivery of antibiotics and other medications, with widespread therapeutic applications. [source] Synthesis and rheological characterization of graft copolymers of butyl and hydroxyethyl methacrylates on starchesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2008Mariló Gurruchaga Abstract To study the possibility of using some acrylic-grafted polysaccharides as matrix tablets, graft copolymers of butyl methacrylate and hydroxyethyl methacrylate on starch and on hydroxypropyl starch were synthesized. In this work, the effects of the different chemical compositions of the various synthesized graft copolymers on the hydrophilicity and rheological characteristics were examined. Water absorption values that ranged from 5 to 45% were obtained. Rheological testing determined with dispersions (5% w/w) in water showed that the graft copolymers formed weak gels of high viscosity. Moreover, the synthesized powders showed good flow and good compaction. These measurements pointed toward the possibility of their application for drug release. © 2008 Wiley Periodicals, Inc. 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