Showing papers on "Glycidyl methacrylate published in 2001"

Modification of crosslinked glycidyl methacrylate-based polymers for boron-specific column extraction

Abstract: Terpolymers of glycidyl methacrylate (0.4 mol) with methyl methacrylate (0.5 mol) and divinyl benzene (0.1 mol) in spherical beads form have been modified with N -methyl- d -glucamine in N -methyl pyrrolidone solvent. Polymers with (2.05 mmol g −1 ) functionality have moderate swelling ability (1.81 v / v 0 ) and show excellent boron uptake ability (2.15 mmol g −1 ) for extraction of trace quantities of H 3 BO 3 from aqueous solutions. The resinous polymer with 110–210 μm size has a reasonable breakthrough capacity (0.835 mmol g −1 ) and a sharp elution profile in the column extractions. No interferences come from Ca(II), Mg(II) and Fe(III) ions (0.1 M), though slightly in the presence of these ions due to coprecipitation of borates by the metal hydroxides formed on the resin particles. The capacity of the resin and flow rate do not change even after 20 recyclings in the column extractions. The method has been shown to be promising for large-scale boron extractions from aqueous solutions.

Dispersion polymerization of glycidyl methacrylate in supercritical carbon dioxide

Abstract: Herein we report a successful dispersion polymerization of glycidyl methacrylate (GMA) in carbon dioxide using a block copolymer consisting of polystyrene and poly(1,1-dihydroperfluorooctyl acrylate) (PFOA) as a stabilizer. Poly(GMA) was effectively emulsified in carbon dioxide using the amphiphilic diblock copolymer surfactant. Spherical particles were produced, although PFOA homopolymer was not particularly effective as a stabilizer. The initial concentrations of the monomer and stabilizer and the reaction pressure had substantial effects on the resulting size of the colloidal particles.

Biologically active polymers. IV. Synthesis and antimicrobial activity of polymers containing 8‐hydroxyquinoline moiety

Abstract: Polymers containing 8-hydroxyquinoline moiety were prepared. Modifications of the base polymer of glycidyl methacrylate were carried out in order to introduce chloromethyl groups, either by the hydrolysis of the poly(glycidyl methacrylate) and the chloroacetylation of the hydrolyzed polymer by the reaction with chloroacetyl chloride or by aminating the poly(glycidyl methacrylate) either with ethylenediamine or with hexamethylenediamine, followed by reacting the aminated polymers with chloroacetyl chloride. The polymers containing 8-hydroxyquinoline moiety were prepared by reacting the chloromethyl groups containing polymers with potassium salt of 8-hydroxy quinoline. The antimicrobial activity of the polymers obtained was examined against gram-negative bacteria (Escherichia coli) and gram-positive bacteria (Bacillus subtilus) as well as the fungus Trichophyton rubrum. Generally, all three polymers proved effective against the tested microorganisms, but growth inhibitory effects varied from one another. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1364–1374, 2001

Environmentally benign formation of polymeric microspheres by rapid expansion of supercritical carbon dioxide solution with a nonsolvent.

Abstract: A novel method is reported for forming polymer microparticles, which reduce atmospheric emissions of environmentally harmful volatile organic compounds such as toluene and xylene used as paint solvent in paint industry. The polymer microparticles have formed through rapid expansion from supercritical solution with a nonsolvent (RESS-N). Solubilization of poly(styrene)-b-(poly(methyl methacrylate)-co-poly (glycidyl methacrylate)) copolymer (PS-b-(PMMA-co-PGMA), MW = 5000, PS/PMMA/PGMA = 2/5/3), poly(ethylene glycol) (PEG, M. W = 4000), bisphenol A type epoxy resin (EP, MW = 3000), poly(methyl methacrylate) (PMMA; MW = 15 000, 75 000, 120 000), and poly(oxyalkylene) alkylphenyl ether (MW = 4000) in carbon dioxide (CO2) was achieved with the use of small alcohols as cosolvents. The solubility of the PS-b-(PMMA-co-PGMA) is extremely low in either CO2 or ethanol but becomes 20 wt % in a mixture of the two. Because ethanol is a nonsolvent for the polymer, it can be used as a cosolvent in rapid expansion from su...

Dental composites reinforced with hydroxyapatite: mechanical behavior and absorption/elution characteristics.

Abstract: The purpose of this study was to analyze the behavior in water as well as the mechanical and surface properties of experimental composites designed for dental restoration. Studied materials were composed of a visible- light-cured monomer mixture as a matrix (bisphenol-a- glycidyl methacrylate with triethyleneglycol dimethacrylate or hydroxyethyl methacrylate) and either micrometric or nanometric hydroxyapatite (HA) particles as a reinforcing filler. The surface of the filler particles was modified by using different coupling agents (citric, hydroxysuccinic, acrylic, or methacrylic acid). The hydrolytic stability of the evaluated materials was studied through elution-in-water and water-uptake tests. Mechanical and surface properties were examined through the results of flexural, hardness, and surface roughness tests. Means and standard deviations were calculated for each variable. Analysis of variance and multiple comparison tests were performed. Materials con- taining bisphenol-a-glycidyl methacrylate:triethyleneglycol dimethacrylate and micrometric-HA coated with citrate, ac- rylate, or methacrylate displayed the most favorable results. Improvements should be obtained by increasing the total filler amount, and by the introduction of nanometric-HA filler into a micrometric-HA reinforced composite resin sys- tem. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res 56: 297-305, 2001

Glycidyl methacrylate based polymer resins with diethylene triamine tetra acetic acid functions for efficient removal of Ca(II) and Mg(II)

Abstract: Crosslinked terpolymer beads prepared by suspension polymerization of glycidyl methacrylate (GMA) (0.4 mol), methyl methacrylate (MMA) (0.5 mol) and divinyl benzene (DVB) (0.1 mol) mixtures have been modified through epoxy functions in two steps: (i) by treating with excess of diethylene triamine (DETA); and (ii) by subsequent reaction with potassium chloroacetate. The resulting polymer possessing diethylene triamine tetra acetic acid (DTTA) functions (with degree of functionalization DF:1.70 mmol·g −1 ) is an efficient sorbent for removal of Ca (II) and Mg (II) ions in ppm levels. Interestingly when the sodium form of the resin is used in relatively high concentrations (0.1 M) sorbed amounts will be 10–45% in excess of the theoretical capacity due to precipitation of the metal hydroxides on polymer particles beside chelation with the metal ions. Having EDTA-like chelating units, the polymer is able to absorb also heavy metal ions such as Fe (III), Zn (II), Cd (II), Pb (II), Ni (II), Cu (II), Co (II) ions. Not having hydrolysable linkages, metal-free resins can be obtained by acid treatment (4 M HCl) without loosing its activity. The resin with DTTA functions seems to be applicable in large scale water softening processes.

Affinity monoliths generated by in situ polymerization of the ligand.

Abstract: An affinity monolith with a novel immobilization strategy was developed leading to a tailored pore structure. Hereby the ligand is conjugated to one of the monomers of the polymerization mixture prior to polymerization. After the polymerization, a monolithic structure was obtained either ready to use for affinity chromatography or ready for coupling of additional ligand to further increase the binding capacity. The model ligand, a peptide directed against lysozyme, was conjugated to glycidyl methacrylate prior to the polymerization. With this conjugate, glycidyl methacrylate, and ethylene dimethacrylate, a monolith was formed and tested with lysozyme. A better ligand presentation was achieved indicated by the higher affinity constant compared to a conventional sorbent.

Immobilization of invertase on a new type of macroporous glycidyl methacrylate

Abstract: Invertase was immobilized via its carbohydrate moiety. The immobilized enzyme has a specific activity of 5500 IU g−1, with 45% activity yield on immobilization. In a packed bed reactor, 90% 2.5 M sucrose was converted at a flow rate of 4 bed volumes h−1. The obtained specific productivity at 40 °C of 3 kg l−1 h−1 is the best one so far. Long-term stability was 290 days in 2.5 M sucrose at 40 °C and at a flow rate of 3 bed volumes h−1.

Fracture toughness assessment of poly(ethylene terephthalate) blends with glycidyl methacrylate modified polyolefin elastomer using essential work of fracture method

Abstract: The static fracture toughness of poly(ethylene terephthalate) (PET) melt blended with a modifier containing glycidyl methacrylate (GMA)-grafted ethylenepropylene rubber and homopolymerized GMA was studied on injection molded specimens by adopting the essential work of fracture (EWF) method. It was found that the essential and nonessential or plastic work both decrease with an increasing amount of modifier (up to 20 wt %) if the PET matrix is amorphous and nonaged. The scatter in the EWF data for the blend with 10 wt % modifier was found by presuming concurrent mechanisms between microcrystallization and morphology-dependent cavitation and fibrillation processes.

Photochemical reactions of quaternary ammonium dithiocarbamates as photobase generators and their use in the photoinitiated thermal crosslinking of poly(glycidyl methacrylate)

Abstract: The photochemical behavior of quaternary ammonium salts (QA salts) with N,N-dimethyldithiocarbamate as photobase generators and the photoinitiated thermal crosslinking of poly(glycidyl methacrylate) (PGMA) with the QA salts were investigated. The formation of basic compounds in the photolysis of 1-phenacyl-(1-azonia-4-azabicyclo[2,2,2]octane) N,N-dimethyldithiocarbamate was ascertained by the color change of phenol red as an acid–base indicator. 1H NMR spectra of photoproducts in CDCl3 under N2 showed that the photolysis of 1-naphthoylmethyl-(1-azonia-4-azabicyclo[2,2,2]octane) N,N-dimethyldithiocarbamate resulted in the quantitative formation of triethylenediamine and a dithiocarbamate derivative. The presence of oxygen in the photolysis decreased the photolysis rate. The amine was also detected in its photolysis in polystyrene films. The effects of ammonio groups and counteranions of QA salts on the photoinitiated thermal crosslinking of PGMA films were also investigated. Quaternary ammonium dithiocarbamates acted as excellent photobase generators and effective photoinitiated thermal crosslinkers for PGMA. © 2001 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 39: 1329–1341, 2001

Studies on copolymerization of n‐isopropylacrylamide and glycidyl methacrylate

Abstract: Free-radical homopolymerization of N-isopropyl acrylamide (NIPA, monomer 1) and copolymerizations of NIPA with glycidyl methacrylate (GMA, monomer 2) were conducted in deuterated dioxane at 70 °C. The conversion of the monomers was followed by 1H NMR spectroscopy. After the polymerization reactions the polymers were precipitated and analyzed. Reactivity ratios were determined using both Fineman–Ross and extended Kelen–Tudős methods. Values obtained by these two methods were r1 = 0.39, r2 = 2.69 and r1 = 0.30, r2 = 2.66, respectively. In both cases, r ∼ 1, which is indicative of an ideal copolymerization resulting in a first-order Markov distribution of the monomers in the final copolymer. The compositional heterogeneities of the polymers were estimated by following the instantaneous copolymer compositions as functions of conversion. Given the different reactivities of the two monomers it is concluded that a copolymer with a homogeneous distribution of monomers may be obtained not by a batch reaction, but by slowly and continuously adding GMA into the polymerizing reaction mixture. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 3716–3725, 2001

Influence of the immobilisation process on the activity of β-galactosidase bound to nylon membranes grafted with glycidyl methacrylate: Part 2. Non-isothermal behaviour

Abstract: β-Galactosidase was immobilised via diazotisation or condensation on nylon membranes, chemically grafted with glycidyl methacrylate (GMA) and having identical physical transport properties, such as hydraulic and thermoosmotic permeabilities. Immobilisation by diazotisation involves the binding of the enzyme to the activated membranes through the tyrosine residues of the macromolecule, while immobilisation by condensation occurs through arginine residues. The performance of both membranes types was studied as a function of substrate concentration, average temperature and temperature gradients in a bioreactor operating under non-isothermal conditions. Both membrane types exhibit apparent K m values of the immobilised form higher than that of the free enzyme. Under non-isothermal conditions the apparent K m of the immobilised β-galactosidase approached values more close to that of the free enzyme, recovering in this way the loss of affinity consequent to the immobilisation process. Moreover, membranes obtained via diazotisation resulted more efficient than those obtained via condensation, showing higher percentage activity increases with respect to all the experimental variables studied. This behaviour has been attributed to the different immobilisation technique, since the multipoint enzyme attachment through the arginine residues of the macromolecule affects the catalytic structure of the catalytic site more than the attachment by diazotisation. Activity increases under non-isothermal conditions were found to decrease with the increases of substrate concentration and average temperature. The values of the yield increases with 1 °C of temperature difference across both catalytic membranes confirm the useful employment of the technology of the non-isothermal bioreactors in productive biotechnological processes.

Functionalization of high-density polyethylene in the molten state by glycidyl methacrylate grafting

Abstract: :This study concerns the melt-free radical grafting of glycidyl methacrylate (GMA) onto high-density polyethylene (HDPE). We studied the effect of two initiators (tert-butyl cumyl peroxide and di-tert-butyl peroxide) onto HDPE. Crosslinking of polymer was observed in the presence of 0.3 wt % tert-butyl cumyl peroxide but not with 0.3 wt % di-tert-butyl peroxide. The grafting was carried out in a Brabender batch mixer at 190 °C. The grafting yield of GMA onto HDPE (determined by infrared spectrometry) is weak (<1 wt % for an initial concentration in monomer of 6 wt %). Moreover, it was noted that the degree of grafting did not vary with the concentration and the nature of peroxide used. To increase the grafting yield of GMA, we added to the HDPE/peroxide/GMA system an electron-donating monomer, such as styrene. Adding this comonomer multiplied the rate of grafted GMA 3- or 4-fold, resulting in a ratio [styrene]i/[GMA]i = 1 mol/mol with [GMA]i = 6 wt %. So, the copolymerization is favored compared with the homopolymerization. This kind of copolymer presenting reactive functions is very attractive in the field of compatibilizing immiscible polymers. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 581–590, 2001

Semipreparative capillary electrochromatography

Abstract: Capillaries with inner diameters of 550 microm have successfully been packed with 1.5-microm octadecyl silica particles using frits made of macroporous polymers by the UV photopolymerization of a solution of glycidyl methacrylate and trimethylolpropane trimethacrylate. This type of frit is found superior to one made of low-melting point poly(styrene-co-divinylbenzene) beads. Bubble formation is not observed to occur within these capillary columns under our experimental conditions. Separations can be achieved with sample injection volumes as high as 1 microL. To demonstrate its semipreparative use, a mixture of 500 nL of taxol (20 mM) and its precursor, baccatin III (30 mM), is separated using such a column with a Tris buffer.

Kinetic model of a methacrylate-based monolith polymerization

Abstract: Monolithic stationary phases are becoming more and more important in the field of liquid chromatography, because they enable extremely fast separations. Methacrylate-based monoliths are produced via a free-radical bulk polymerization of glycidyl methacrylate and ethylene dimethacrylate using a benzoyl peroxide as an initiator. Preparation of large monoliths represents a big problem because of the heat release during the polymerization, which consequently leads to the distortion of the structure. A closer investigation of the polymerization, using differential scanning calorimetry, was performed in order to determine global kinetic parameters. A multiple heating rate method, based on the work of Ozawa, Flynn, and Wall, was applied for estimation of the values of the apparent activation energy, preexponential factor, and reaction order. Global polymerization kinetics is of first order with A = 1.681 × 10 9 s -1 and E a,app = 81.5 kJ/mol, where the heat of polymerization is approximately 190 J/g. In addition, the influence of air and nitrogen atmosphere on polymerization is presented.

Reactive processing of polymers : Melt grafting of glycidyl methacrylate on ethylene propylene copolymer in the presence of a coagent

Abstract: Glycidyl methacrylate (GMA) was grafted on ethylene-propylene copolymer during melt processing with peroxide initiation in the presence and absence of a more reactive comonomer (coagent), trimethylolpropane triacrylate (Tris). The characteristics of the grafting systems in terms of the grafting reaction yield and the nature and extent of the competing side reactions were examined. The homopolymers of GMA (Poly-GMA) and Tris (Poly-Tris) and the GMA-Tris copolymer (GMA-co-Tris) were synthesized and characterized. In the absence of the coagent, high levels of poly-GMA, which constituted the major competing reaction, was formed, giving rise to low GMA grafting levels. Further, this grafting system resulted in a high extent of gel formation and polymer crosslinking due to the high levels of peroxide needed to achieve optimum GMA grafting and a consequent large drop in the melt index (increased viscosity) of the polymer. In the presence of the coagent, however, the grafting system required much lower peroxide concentration, by almost an order of magnitude, to achieve the optimum grafting yield. The coagent-containing GMA-grafting system has also resulted in a drastic reduction in the extent of all competing reactions, and in particular, the GMA homopolymerization, leading to improved GMA grafting efficiency with no detectable gel or crosslinking. The mechanisms of the grafting reactions, in the presence and absence of Tris, are proposed.

Albumin release from biodegradable hydrogels composed of dextran and poly(ethylene glycol) macromer.

Abstract: Biodegradable hydrogels based on glycidyl methacrylate dextran (GMD) and dimethacrylate poly(ethylene glycol) (DMP) were proposed for colon-specific drug delivery. GMD was synthesized by coupling of glycidyl methacrylate with dextran in the presence of 4-(N,N-dimethyl-amino)pyridine (DMAP) using dimethylsulfoxide as a solvent. Methacrylate-terminated poly (ethylene glycol) (PEG) macromer was prepared by the reaction of PEG with methacryloyl chloride. GMD/DMP hydrogels were prepared by radical polymerization of phosphate buffer solution (0.1M, pH 7.4) of GMD and DMP, using ammonium peroxydisulfate (APS) and UV as initating system. The synthetic GMD, DMP, and GMD/DMP hydrogels were characterized by fourier transform infrared (FT-IR) spectroscopy. The FITC-albumin loaded hydrogels were prepared by adding FITC-albumin solution before UV irradiation. Swelling capacity of GMD/DMP hydrogels was controlled not only by molecular weight of dextran, but also by incorporation ratio of DMP. Degradation of the hydrogels has been studied in vitro with dextranase. FITC-albumin release from the GMD/DMP hydrogels was affected by molecular weight of dextran and the presence of dextranase in the release medium.

New biodegradable hydrogels based on a photo-cross-linkable polyaspartamide and poly(ethylene glycol) derivatives. Release studies of an anticancer drug

Abstract: The functionalization of α,β-poly(N-2-hydroxyethyl)-dl-aspartamide (PHEA) with glycidyl methacrylate (GMA) gives rise to a water-soluble photosensitive copolymer PHEA-GMA (PHG). Aqueous solutions of PHG alone or in combination with various concentrations of poly(ethylene glycol) dimethacrylate or poly(ethylene glycol) diacrylate (PEGDA) have been exposed to a source of UV rays at 313 nm in order to obtain polymeric networks. All samples have been prepared both as water-swellable microparticles and as gel systems. Microparticles have been characterised by Fourier transform IR spectrophotometry, dimensional analysis and swelling measurements in aqueous media mimicking biological fluids. In vitro chemical and enzymatic hydrolysis studies showed that all the prepared samples undergo a partial degradation at pH 1, 7.4 and 10 as well as after incubation with enzymes such as esterase. The effect of the cross-linking density on the rheological behavior of gel systems has also been investigated. PHG/PEGDA hydrogel is able to incorporate, during UV-irradiation, 5-fluorouracil (5-FU), chosen as a model drug, and to release it in simulated biological fluids, as confirmed by in vitro drug release studies at pH 1 and 7.4. PHG/PEGDA gel containing 5-FU is able to release this drug in a prolonged way, more slowly than a commercial ointment, as confirmed by in vitro studies at pH 5.5 and 7.4 using a Franz diffusion cell system and a synthetic membrane.

Oxidative graft polymerization of aniline on modified Si(100) surface

Abstract: Chemical modification of the argon plasma-pretreated Si(100) surface by UV-induced surface graft polymerization with either glycidyl methacrylate (GMA) or glycidyl acrylate (GA) was carried out. The GA graft polymerized Si substrate was further subjected to coupling reaction with aniline (An) and finally oxidative graft polymerization of An. The composition and microstructure of the graft-polymerized Si(100) surfaces were studied by X-ray photoelectron spectroscopy (XPS) and imaging XPS, respectively. The graft concentrations of the GMA polymer, GA polymer, and An polymer increased with increasing concentration of the respective monomer used for graft polymerization. The graft polymerization efficiency of GA on the Ar plasma-pretreated Si(100) was much higher than that of GMA. Ethanol, when used as a solvent, catalyzed the coupling reaction of the epoxide groups of GA with An and should be of more than 40 vol % in concentration to achieve the optimum effect. The protonation−deprotonation characteristics, ...

Efforts to decrease crosslinking extent of polyethylene in a reactive extrusion grafting process

Abstract: Grafting of acrylic acid and glycidyl methacrylate onto low density polyethylene (LDPE) was performed by using a corotating twin-screw extruder. The effects of residence time and concentration of initiator and monomers on degree of grafting and gel content of grafting LDPE were studied systematically. Paraffin, styrene, p-benzoquinone, triphenyl phosphite, tetrachloromethane, and oleic acid were added to try to decrease the extent of crosslinking of LDPE. 4-hydroxyl-2,2,6,6-tetramethyl-1-piperidinyloxy (4-hydroxyl-TEMPO) and dipentamethylenethiuram tetrasulfide were also tried to inhibit crosslinking reaction of LDPE during its extruding grafting process. It was found that p-benzoquinone, triphenyl phosphite and tetrachloromethane were good inhibitors for crosslinking of LDPE. (C) 2000 John Wiley & Sons, Inc.