Adsorption of IgG on spacer‐arm and L‐arginine ligand attached poly(GMA/MMA/EGDMA) beads

This work presents data on human immunoglobulin G (HIgG) adsorption onto L ‐arginine ligand attached poly(GMA/MMA/EGDMA)‐based affinity beads which were synthesized from methyl methacrylate (MMA) and glycidiyl methacrylate (GMA) in the presence of a crosslinker (i.e., ethylene glycol dimethacrylate; EGDMA) by suspension polymerization. The epoxy groups of the poly(GMA/MMA/EGDMA) beads were converted into amino groups after reaction with ammonia or 1,6‐diaminohexane (i.e., spacer‐arm). With L ‐arginine as a ligand, it was covalently immobilized on the aminated (poly(GMA/MMA/EGDMA)‐ AA) and/or the spacer‐arm attached (poly(GMA/MMA/EGDMA)‐SA) beads, using glutaric dialdehyde as a coupling agent. Both affinity poly(GMA/MMA/EGDMA)‐based beads were used in HIgG adsorption/desorption studies under defined pH, ionic strength, or temperature conditions in a batch reactor, using acid‐treated poly(GMA/MMA/EGDMA) beads as a control system. The poly(GMA/MMA/EGDMA)‐SA affinity beads resulted in an increase in the adsorption capacity to HIgG compared with the aminated counterpart (i.e., poly(GMA/MMA/EGDMA)‐AA). The maximum adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA affinity beads were found to be 112.36 and 142 mg g^?1, and the affinity constants (K_d), evaluated by the Langmuir model, were 2.48 × 10^?7 and 6.98 × 10^?7M, respectively. Adsorption capacities of the poly(GMA/MMA/EGDMA)‐AA and poly(GMA/MMA/EGDMA)‐SA were decreased with HIgG by increasing the ionic strength adjusted with NaCl. Adsorption kinetic of HIgG onto both affinity adsorbents was analyzed with first‐ and second‐order kinetic equations. The first‐order equation fitted well with the experimental data. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 672–679, 2007     

Chitosan‐grafted poly(hydroxyethyl methacrylate‐co‐glycidyl methacrylate) membranes for reversible enzyme immobilization

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 K_m 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     

Synthesis and characterization of magnetic beads containing aminated fibrous surfaces for removal of Reactive Green 19 dye: kinetics and thermodynamic parameters

BACKGROUND: Poly(HEMA‐co‐MMA) beads were prepared from 2‐hydroxyethyl‐methacrylate (HEMA) and methylmethacrylate (MMA) in the presence of FeCl₃. Thermal co‐precipitation of Fe(III) ions containing beads with Fe(II) ions was carried out under alkaline conditions. The magnetic beads were grafted with poly(glycidylmethacrylate; p(GMA)), and the epoxy groups of the grafted p(GMA) brushes were converted into amino groups by reaction with ammonia. RESULTS: The magnetic beads were characterized by surface area measurement, electron spin resonance (ESR), Mössbauer spectroscopy and scanning electron microscopy (SEM). The maximum adsorption of Reactive Green‐19 (RG‐19) dye on the p(GMA) grafted and amine modified magnetic beads was around pH 3.0. The adsorption capacity of magnetic beads was 84.6 mg dye g^?1. The effects of adsorbent dosage, ionic strength and temperature have also been reported. Batch kinetic sorption experiments showed that a pseudo‐second‐order rate kinetic model was applicable. CONCLUSION: The p(GMA) grafted and amine modified magnetic beads (adsorbent) were expected to have the advantage of mobility of the grafted chains in the removal of acidic dyes from aqueous solutions. The magnetic beads have potential as an adsorbent for removal of pollutants under various experimental conditions without significant reduction in their initial adsorption capacity. Copyright © 2011 Society of Chemical Industry     

Immobilization of Candida lipolytica lipase on macroporous beaded terpolymers with epoxy groups

A series of macroporous beaded terpolymers with epoxy groups were synthesized by suspension polymerization with glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA), and the third monomers including styrene, methyl methacrylate, n‐butyl acrylate (BA), butyl methacrylate (BMA), and 2‐hydroxyethyl methacrylate for immobilization of Candida lipolytica lipase. The effect of various third monomers on loading and activity recovery of immobilized lipase were studied. Terpolymers with BA as the third monomer were found to give the biggest loading of lipase, and the activity recovery of lipase immobilized on poly(GMA‐EGDMA‐BA) terpolymers reached 79.0%. As the content of BA (%) increasing, the loading of lipase enhanced, but the activity recovery reached 88.5% for the initial stage and decreased to 46.9% at last. The poly(GMA‐EGDMA‐BA‐10) showed an optimal result in lipase immobilization. Lipase immobilized on poly(GMA‐EGDMA‐BA‐10) carriers had broader pH and higher temperature stability. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Immobilization of invertase onto crosslinked poly(p‐chloromethylstyrene) beads

Invertase was immobilized onto poly(p‐chloromethylstyrene) (PCMS) beads that were produced by a suspension polymerization with an average size of 186 μm. The beads had a nonporous but reasonably rough surface. Because of this, a reasonably large external surface area (i.e., 14.1 m²/g) could be achieved with the proposed carrier. A two‐step functionalization protocol was followed for the covalent attachment of invertase onto the bead surface. For this purpose, a polymeric ligand that carried amine groups, polyethylenimine (PEI), was covalently attached onto the bead surface by a direct chemical reaction. Next, the free amine groups of PEI were activated by glutaraldehyde. Invertase was covalently attached onto the bead surface via the direct chemical reaction between aldehyde and amine groups. The appropriate enzyme binding conditions and the batch‐reactor performance of the immobilized enzyme system were investigated. Under optimum immobilization conditions, 19 mg of invertase was immobilized onto each gram of beads with 80% retained activity after immobilization. The effects of pH and temperature on the immobilized invertase activity were determined and compared with the free enzyme. The kinetic parameters K_M and V_M were determined with the Michealis–Menten model. K_M of immobilized invertase was 1.75 folds higher than that of the free invertase. The immobilization caused a significant improvement in the thermal stability of invertase, especially in the range of 55–65°C. No significant internal diffusion limitation was detected in the immobilized enzyme system, probably due to the surface morphology of the selected carrier. This result was confirmed by the determination of the activation energies of both free and immobilized invertases. The activity half‐life of the immobilized invertase was approximately 5 times longer than that of the free enzyme. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1268–1279, 2002     

Vinyl triazole carrying metal‐chelated beads for the reversible immobilization of glucoamylase

Poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [poly(EGDMA–VTAZ)] beads with an average diameter of 100–200 μm were obtained by the copolymerization of ethylene glycol dimethacrylate (EGDMA) with 1‐vinyl‐1,2,4‐triazole (VTAZ). The copolymer hydrogel bead composition was determined by elemental analysis and was found to contain 5 EGDMA monomer units for each VTAZ monomer unit. The poly(EGDMA–VTAZ) beads were characterized by swelling studies and scanning electron microscopy (SEM). The specific surface area of the poly(EGDMA–VTAZ) beads was found 65.8 m²/g. Cu²⁺ ions were chelated on the poly(EGDMA–VTAZ) beads. The Cu²⁺ loading was 82.6 μmol/g of support. Cu²⁺‐chelated poly(EGDMA–VTAZ) beads with a swelling ratio of 84% were used in the immobilization of Aspergillus niger glucoamylase in a batch system. The maximum glucoamylase adsorption capacity of the poly(EGDMA–VTAZ)–Cu²⁺ beads was 104 mg/g at pH 6.5. The adsorption isotherm of the poly(EGDMA–VTAZ)–Cu²⁺ beads fitted well with the Langmuir model. Adsorption kinetics data were tested with pseudo‐first‐ and second‐order models. The kinetic studies showed that the adsorption followed a pseudo‐second‐order reaction model. The Michaelis constant value for the immobilized glucoamylase (1.15 mg/mL) was higher than that for free glucoamylase (1.00 mg/mL). The maximum initial rate of the reaction values were 42.9 U/mg for the free enzyme and 33.3 U/mg for the immobilized enzyme. The optimum temperature for the immobilized preparation of poly(EGDMA–VTAZ)–Cu²⁺–glucoamylase was 65°C; this was 5°C higher than that of the free enzyme at 60°C. The glucoamylase adsorption capacity and adsorbed enzyme activity slightly decreased after 10 batch successive reactions; this demonstrated the usefulness of the enzyme‐loaded beads in biocatalytic applications. The storage stability was found to increase with immobilization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Surface modification of nylon membrane by glycidyl methacrylate graft copolymerization for antibody immobilization

Surface of nylon membrane was modified by the graft copolymerization of glycidyl methacrylate (GMA) using persulfate and thiosulfate as redox initiator system. Effect of various reaction parameters such as initiator concentration, monomer concentration, polymerization time, and temperature on degree of grafting was also studied. Maximum grafting of 100% was achieved by using equimolar concentration (0.008M) of redox initiator and 0.5M of GMA monomer at 70°C in 60 min. Grafted nylon membranes with various graft levels of GMA were characterized by various techniques such as fourier transform infrared spectroscopy, thermo gravimetric analysis, and scanning electron microscopy. The GMA grafted nylon (NyM‐g‐GMA) membranes with different graft levels were evaluated as a support for immobilization of rabbit anti goat antibody (RAG IgG). Antibody (Ab) immobilized NyM‐g‐GMA membranes were evaluated using ELISA and Bradford protein estimation method. Nylon membrane with 60% graft level showed optimum immobilization of Ab at RAG IgG conc. of 0.625 μg/mL with low nonspecific binding. Maximum immobilization efficiency (I.E.%) of 56% was observed for membrane with 60% graft level at 50 μg/mL of RAG IgG in PBS (pH 7.4). Ab immobilized NyM‐g‐GMA discs were found to be stable up to 6 weeks at 4°C and 2 days at 37°C. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Human serum albumin adsorption on poly[(glycidyl methacrylate)‐co‐(methyl methacrylate)] beads modified with a spacer‐arm‐attached L‐histidine ligand

Poly(GMA/MMA) beads were synthesized from glycidyl methacrylate (GMA) and methyl methacrylate (MMA) in the presence of a cross‐linker (i.e. ethyleneglycol dimethacrylate) (EGDMA) via suspension polymerization. The epoxy groups of the poly(GMA/MMA) beads were converted into amino groups with either ammonia or 1,6‐diaminohexane (i.e. spacer‐arm). An L ‐histidine ligand was then covalently immobilized on the aminated (poly(GMA/MMA)‐AH) and/or the spacer‐arm attached (poly(GMA/MMA)‐SAH) beads using glutaric dialdehyde as a coupling agent. Both affinity adsorbents were used in human serum albumin (HSA) adsorption/desorption studies under defined pH, ionic strength or temperature conditions in a batch reactor. The spacer‐arm attached affinity adsorbent resulted in an increase in the adsorption capacity to HSA when compared to the aminated counterpart (i.e. poly(GMA/MMA)‐AH). The maximum adsorption capacities of the affinity adsorbents were found to be significantly high, i.e. 43.7 and 80.2 mg g^?1 (of the beads), while the affinity constants, evaluated by the Langmuir model, were 3.96 × 10^?7 and 9.53 × 10^?7 mol L^?1 for poly(GMA/MMA)‐AH and poly(GMA/MMA)‐SAH, respectively. The adsorption capacities of the affinity adsorbents were decreased for HSA by increasing the ionic strength, adjusted with NaCl. The adsorption kinetics of HSA were analysed by using pseudo‐first and pseudo‐second‐order equations. The second‐order equation fitted well with the experimental data. Copyright © 2005 Society of Chemical Industry     

Immobilization horseradish peroxidase on amine-functionalized glycidyl methacrylate-<Emphasis Type="Italic">g</Emphasis>-poly(ethylene terephthalate) fibers for use in azo dye decolorization

Activated fibers were used as a new support material for the immobilization of horseradish peroxidase (HRP). Poly(ethylene terephthalate) (PET) fibers were grafted with glycidyl methacrylate (GMA) using benzoyl peroxide (Bz₂O₂) as initiator. 1,6-diaminohexane (HMDA) was then covalently attached to this GMA grafted PET fibers. HMDA-GMA-g-PET fibers were activated with glutaraldehyde and HRP was successfully immobilized. Both on the free HRP and the immobilized HRP activities, pH, temperature, thermal stability, and reusability were investigated. Both free enzyme and immobilized enzyme were used in a batch process for the degradation of azo dye. About 98% of azo dye removal was observed with immobilized HRP, while 79% of azo dye removal was found with the free HRP. 45 min of the contact time is sufficient for the maximum azo dye removal. The HRP immobilized on modified PET fibers were very effective for removal of azo dye from aqueous solutions.     

Adsorption of trypsin onto magnetic ion‐exchange beads of poly(glycidylmethacrylate‐co‐ethyleneglycoldimethacrylate)

Magnetic beads were prepared from glycidyl methacrylate (GMA), and ethyleneglycol dimethylmethacrylate (EGDMA) in the presence of Fe₃O₄ nano‐powder via suspension polymerization. The magnetic beads were characterized by surface area measurement, electron spin resonance (ESR), and scanning electron microscopy (SEM). ESR data revealed that the beads were highly super‐paramagnetic. The effects of contact time, pH, ionic strength, and temperature on the adsorption process have been studied. Adsorption equilibrium was established in about 120 min. The maximum adsorption of trypsin on the magnetic beads was obtained as 84.96 mg g^?1 at around pH 7.0. At increased ionic strength, the contribution of the electrostatic component to the overall binding decreased, and so the adsorption capacity. The experimental equilibrium data obtained trypsin adsorption onto magnetic beads fitted well to the Langmuir isotherm model. The result of kinetic analyzed for trypsin adsorption onto magnetic ion‐exchange beads showed that the second order rate equation was favorable. It was observed that after six adsorption–elution cycle, magnetic beads can be used without significant loss in trypsin adsorption capacity. Finally, the magnetic beads were used for separation of bovine serum albumin (BSA) and trypsin from binary solution in a batch system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Porous dye affinity beads for albumin separation from human plasma

Porous polymeric beads were obtained by the suspension polymerization of 2‐hydroxyethyl methacrylate (HEMA) and ethylene glycol dimethacrylate (EGDMA). Poly(HEMA–EGDMA) beads were characterized by surfacearea measurements, swelling studies, FTIR, scanning electron microscopy (SEM), and elemental analysis. Poly (HEMA–EGDMA) beads had a specific surface area of 56 m²/g. SEM observations showed that the poly(HEMA–EGDMA) beads abounded macropores. Poly(HEMA–EGDMA) beads with a swelling ratio of 55%, and containing different amounts of Reactive Red 120 (9.2–39.8 μmol/g) were used in the adsorption/desorption of human serum albumin (HSA) from aqueous solutions and human plasma. The nonspecific adsorption of HSA was very low (0.2 mg/g). The maximum HSA adsorption amount from aqueous solution in phosphate buffer was 60.1 mg/g at pH 5.0. Higher HSA adsorption value was obtained from human plasma (up to 95.7 mg/g) with a purity of 88%. The equilibrium monolayer adsorption amount, Q_max was determined as 172.4 mg/g. The dimensionless separation factor (R_L) value shows that the adsorption behavior of HSA onto the Reactive Red 120 attached poly(HEMA–EGDMA) beads was favorable (0 < R_L < 1). Desorption of HSA from Reactive Red 120 attached poly (HEMA–EGDMA) beads was performed using 0.1M Tris/HCl buffer containing 0.5M NaCl. It was observed that HSA could be repeatedly adsorbed and desorbed with Reactive Red 120‐attached poly(HEMA–EGDMA) beads without significant loss in the adsorption amount. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

High impact poly(lactic acid)/poly(ethylene octene) blends prepared by reactive blending

Poly(ethylene octene) grafted with glycidyl methacrylate (POE‐g‐GMA) was prepared and used to toughen poly (lactic acid) (PLA) via reactive blending. It was found that the notched Izod impact strength of PLA/POE‐g‐GMA blends improved dramatically when the content of elastomer was higher than 10 wt%. Reactive compatibilization between PLA and POE‐g‐GMA were studied by Fourier transform infrared spectroscopy (FTIR) and “Molau test,” the results showed the end carboxyl groups of PLA reacted with the epoxide groups of POE‐g‐GMA during blending. This considerably improved the compatibilization, leading to better wetting of the dispersed phase by the PLA matrix and finer dispersed POE‐g‐GMA particles with narrow distribution. Moreover, the critical interparticle distance (L_c) of the dispersed domains for PLA/POE‐g‐GMA blends system at room temperature was also identified. POLYM. ENG. SCI., 2013. © 2012 Society of Plastics Engineers     

Synthesis and characterization of poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) copolymer beads for heavy‐metal removal

We prepared poly(ethylene glycol dimethacrylate–1‐vinyl‐1,2,4‐triazole) [poly(EGDMA–VTAZ)] beads (average diameter = 150–200 μm) by copolymerizing ethylene glycol dimethacrylate (EGDMA) with 1‐vinyl‐1,2,4‐triazole (VTAZ). The copolymer composition was characterized by elemental analysis and found to contain five EGDMA monomer units for each VTAZ monomer unit. The poly(EGDMA–VTAZ) beads had a specific surface area of 65.8 m²/g. Poly(EGDMA–VTAZ) beads were characterized by Fourier transform infrared spectroscopy, elemental analysis, surface area measurements, swelling studies, and scanning electron microscopy. Poly(EGDMA–VTAZ) beads with a swelling ratio of 84% were used for the heavy‐metal removal studies. The adsorption capacities of the beads for Cd(II), Hg(II), and Pb(II) were investigated in aqueous media containing different amounts of these ions (5–750 mg/L) and at different pH values (3.0–7.0). The maximum adsorption capacities of the poly(EGDMA–VTAZ) beads were 85.7 mg/g (0.76 mmol/g) for Cd(II), 134.9 mg/g (0.65 mmol/g) for Pb(II), and 186.5 mg/g (0.93 mmol/g) for Hg(II). The affinity order toward triazole groups on a molar basis was observed as follows: Hg(II) > Cd(II) > Pb(II). pH significantly affected the adsorption capacity of the VTAZ‐incorporated beads. The equilibrium data were well fitted to the Redlich–Peterson isotherm. Consideration of the kinetic data suggested that chemisorption processes could have been the rate‐limiting step in the adsorption process. Regeneration of the chelating‐beads was easily performed with 0.1M HNO₃. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4276–4283, 2006     

Preparation of copolymer brush-type restricted access microspheres with adjustable adsorption selectivity to variety of dyes

Restricted access materials (RAMs) with adjustable selectivity was developed for the removal and detection of residual dyes for the solve problems of dye contamination. In this work, using homemade poly(4-vinylbenzyl chloride-co-divinylbenzene) (P_VBC/DVB) microspheres as substrate and successive two-step surface-initiated atom transfer radical polymerization (SI-ATRP) as synthesis method, the two types of monomers, sodium 4-vinylbenzene sulfonate (Nass) and styrene (St) were first grafted for constructing mixed interactions of adsorption sites, and then the hydrophilic glycidyl methacrylate (GMA) was polymerized, following by hydrolysis to construct diol groups on the external P_VBC/DVB as the restricted access sites. The developed P_VBC/DVB@poly(St-co-Nass)@poly(GMA) of adsorption properties was investigated by six dyes including methylene blue (MB), basic fuchsin (BF), acid fuchsin (AF), neutral red (NR), methyl orange (MO), and Congo red (CR), the adsorption capacities of those dyes and the removal rate for the binary mixed dye solution both rely on the ratio of St/Nass, confirming the adjustable adsorption selectivity. When P_VBC/DVB@poly(St-co-Nass)@poly(GMA) was packed as solid phase extraction adsorbent in couple with UV–vis spectrum, it was applied to the determination of MB and BF in the water, fish and shrimp, good linearity with satisfactory recoveries for MB and BF are obtained to show the favorable practicability.     

Monodisperse‐porous N‐methyl‐D‐glucamine functionalized poly(vinylbenzyl chloride‐co‐divinylbenzene) beads as boron selective sorbent

To generate a new sorbent with high boron adsorption capacity, we synthesized monodisperse‐porous poly(vinylbenzyl chloride‐co‐divinylbenzene), poly(VBC‐co‐DVB), beads 8.5 μm in size by a new “modified seeded polymerization” technique. By using their chloromethyl functionality, the beads were derivatized by a simple, direct reaction with a boron‐selective ligand, N‐methyl‐D ‐glucamine (NMDG). The selection of poly(VBC‐co‐DVB) beads as a starting material allowed to obtain high boron sensitive‐ligand density on the beads depending on their high chloromethyl content. In the batch adsorption runs performed using NMDG‐attached poly(VBC‐co‐DVB) beads as sorbent, boron removal was efficiently performed in a wide pH range between 4 and 11. Quantitative boron removal was observed with the sorbent concentration of 4 g/L. In the same runs, plateau value of equilibrium adsorption isotherm was obtained as 14 mg boron/g beads. Relatively higher boron adsorption was explained by high ligand density and high specific surface area of the sorbent. Boron adsorption isotherms were analyzed using Langmuir and Freundlich models. In the kinetic runs performed for boron removal, the equilibrium was attained within 10 min at a value of 98%. The fast kinetic behavior was explained by the smaller particle size and enhanced porosity of the new sorbent. Infinite solution volume model and unreacted core model were used to evaluate boron adsorption onto the NMDG‐attached poly(VBC‐co‐DVB) beads. The results indicated that the adsorption process is controlled by the particle‐diffusion step. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Poly(glycidyl methacrylate‐co‐3‐thienyl‐methylmethacrylate) based working electrodes for hydrogen peroxide biosensing

BACKGROUND: Hydrogen peroxide biosensors based on Poly(glycidyl methacrylate‐co‐3‐thienylmethylmethacrylate)/ Polypyrrole [Poly(GMA‐co‐MTM)/PPy] composite film were reported. Poly(GMA‐co‐MTM) including various amounts of GMA and MTM monomers was synthesized via the radical polymerization. Enzyme horseradish peroxidase (HRP) was trapped in Poly(GMA‐co‐MTM)/PPy composites during the electropolymerization reaction between pyrrole and thiophene groups of MTM monomer, and chemically bonded via the epoxy groups of GMA. Analytical parameters of the fabricated electrodes were calculated and are discussed in terms of film electroactivity and mass transfer conditions of the composite films. RESULTS: The amount of electroactive HRP was found to be 1.25, 0.34 and 0.213 µg for the working electrodes of Poly(GMA_30%‐ co‐MTM_70%)/PPy/HRP, Poly(GMA_85%‐co‐MTM_15%)/PPy/HRP and Poly(GMA_90%‐co‐MTM_10%)/PPy/HRP, respectively. Optimal response of the fabricated electrodes was obtained at pH 7 and an operational potential of ? 0.35 V. It was observed that effective enzyme immobilization and electroactivity of the composite films could be changed by changing the ratios of GMA and MTM fractions of Poly(GMA‐co‐MTM) based working electrodes. CONCLUSION: The amount of electroactive enzyme increases with increasing MTM content of the final copolymer. High operational stabilities of the biosensors can be attributed to the strong covalent enzyme linkage via the epoxy groups of GMA due to preventing enzyme deterioration and loss. A more convenient microenvironment for mass transfer was provided for the electrodes by higher GMA ratios. It is observed that mass transfer is dominated by the mechanism of electron transfer to obtain effective sensitivity values. This work contributes to discussions clarifying the problems regarding the design parameters of biosensors. Copyright © 2011 Society of Chemical Industry     

Reactive mixing of PET and PET/PP blends with glycidyl methacrylate–modified styrene‐b‐(ethylene‐co‐olefin) block copolymers

Styrene‐b‐(ethylene‐co‐butylene)‐b‐styrene (SEBS) and styrene‐b‐(ethylene‐co‐propylene) (SEP, SEPSEP) block copolymers with different styrene contents and different numbers of blocks in the copolymer chain were functionalized by melt radical grafting with glycidyl methacrylate (GMA) and employed as compatibilizers for PET‐based blends. Binary blends of PET with both functionalized (SEBS‐g‐GMA, SEP‐g‐GMA, SEPSEP‐g‐GMA) and neat (SEBS, SEP, SEPSEP) copolymers (75 : 25 w/w) and ternary blends of PET and PP (75 : 25 w/w) with various amounts (2.5–10 phr) of both modified and unmodified copolymers were prepared in an internal mixer, and their properties were evaluated by SEM, DSC, melt viscosimetry, and tensile and impact tests. The roles of the chemical structure, grafting degree, and concentration of the various copolymers on blend compatibilization was investigated. The blends with the grafted copolymers showed a neat improvement of phase dispersion and interfacial adhesion compared to the blends with nonfunctionalized copolymers. The addition of grafted copolymers resulted in a marked increase in melt viscosity, which was accounted for by the occurrence of chemical reactions between the epoxide groups of GMA and the carboxyl/hydroxyl end groups of PET during melt mixing. Blends with SEPSEP‐g‐GMA and SEBS‐g‐GMA, at concentrations of 5–10 phr, showed a higher compatibilizing effect with enhanced elongation at break and impact resistance. The effectiveness of GMA‐functionalized SEBS was then compared to that of maleic anhydride–grafted SEBS. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 98: 2201–2211, 2005     

Toughened polyoxymethylene by polyolefin elastomer and glycidyl methacrylate grafted high‐density polyethylene

Ternary blends of polyoxymethylene (POM), polyolefin elastomer (POE), and glycidyl methacrylate grafted high density polyethylene (GMA‐g‐HDPE) with various component ratios were studied for their mechanical and thermal properties. The size of POE dispersed phase increased with increasing the elastomer content due to the observed agglomeration. The notched impact strength demonstrated a parabolic tendency with increasing the elastomer content and reached the peak value of 10.81 kJ/m² when the elastomer addition was 7.5 wt%. The disappearance of epoxy functional groups in the POM/POE/GMA‐g‐HDPE blends indicated that GMA‐g‐HDPE reacted with the terminal hydroxyl groups of POM and formed a new graft copolymer. Higher thermal stability was observed in the modified POM. Both storage modulus and loss modulus decreased from dynamic mechanical analysis tests while the loss factor increased with increasing the elastomer content. GMA‐g‐HDPE showed good compatibility between the POM matrix and the POE dispersed phase due to the reactive compatibilization of the epoxy groups of GMA and the terminal hydroxyl groups of POM. A POM/POE blend without compatibilizer was researched for comparison, it was found that the properties of P‐7.5(POM/POE 92.5 wt%/7.5 wt%) were worse than those of the blend with the GMA‐g‐HDPE compatibilizer. POLYM. ENG. SCI., 57:1119–1126, 2017. © 2017 Society of Plastics Engineers     

Immobilization of β‐galactosidase from Escherichia coli onto modified natural silk fibers

A polymeric support based on the natural silk fibers was prepared and characterized for covalent immobilization of β‐galactosidase from Escherichia coli. The silk fibers were grafted using polyacrylonitrile in presence of benzophenone as a photo‐initiator. The grafted fibers were then activated by treatment with hydrazine hydrate followed by glyoxal cross‐linker. FTIR spectra, scanning electron microscope (SEM) in addition to the staining test derived from the Coomassie protein assay were utilized for investigation of the modification and immobilization steps. Also, the activity of both free and immobilized β‐galactosidase was evaluated as a function of the various important parameters like grafting percentage, pH, and temperature. In addition, the kinetic parameters K_m and v_max for both free and immobilized enzyme were anticipated using Michaelis–Menten equation. The results in this study indicated that the prepared modified woven silk fibers could be used effectively as a polymeric support for immobilization of β‐galactosidase. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2923–2931, 2013     

Adsorptive removal of technetium‐99 using macroporous poly(GMA‐co‐EGDMA) modified with diethylene triamine

The possibility of sorption of technetium‐99 in the form of pertechnetate anion (TcO₄^?) and the sorption kinetics for removing TcO₄^? from aqueous solution by chelating polymers based on glycidyl methacrylate (GMA) were investigated. Two samples of macroporous crosslinked poly(glycidyl methacrylate‐co‐ethylene glycol dimethacrylate) (PGME), with different amount of the crosslinker (ethylene glycol dimethacrylate, EGDMA), were synthesized by suspension copolymerization and functionalized with diethylene triamine (deta). We propose that nonspecific sorption of pertechnetate anion via electrostatic interactions takes place at the protonated amino groups of macroporous crosslinked copolymer. The results of batch experiments performed at pH 1–14 showed fast sorption kinetics for removing TcO₄^? by amino‐functionalized PGME‐deta in a wide range of pH, that is, from 1.0 to 9.0. Almost complete removal of TcO₄^? (91–98%) was reached within 180 min in the stated pH range (1.0–9.0), with the sorption half‐times of under 25 min. The partitioning coefficients of linear adsorption isotherms, with 180‐min equilibrium time, reach the high values of 2130 mL g^?1 and 1698 mL g^?1 for the two samples of synthesized PGME‐deta. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011