Preparation and application in drug controlled delivery of pH‐sensitive P(CE‐co‐DMAEMA‐co‐MEG) hydrogel

A pH‐sensitive hydrogel [P(CE‐co‐DMAEMA‐co‐MEG)] was synthesized by the free‐radical crosslinking polymerization of N,N‐dimethylaminoethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether methacrylate(MPEG‐Mac) and methoxyl poly(ethylene glycol)‐poly(caprolactone)‐methacryloyl methchloride (PCE‐Mac). The effects of pH and monomer content on swelling property, swelling and deswelling kinetics of the hydrogels were examined and hydrogel microstructures were investigated by SEM. Sodium salicylate was chosen as a model drug and the controlled‐release properties of hydrogels were pilot studied. The results indicated that the swelling ratios of the gels in stimulated gastric fluids (SGF, pH = 1.4) were higher than those in stimulated intestinal fluids (SIF, pH = 7.4), and followed a non‐Fickian and a Fickian diffusion mechanism, respectively. In vitro release studies showed that its release rate depends on different swelling of the network as a function of the environmental pH and DMAEMA content. SEM micrographs showed homogenous pore structure of the hydrogel with open pores at pH 1.4. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40737.     

Synthesis and phase separation of poly(N‐isopropyl acrylamide‐co‐methoxy polyethyleneglycol monomethacrylate)

The poly(N‐isopropyl acrylamide‐co‐methoxy polyethyleneglycol monomethacrylate, NIPAM‐co‐MPEG) with different length of ethylene oxide (EO) were synthesized from their monomers, NIPAM and MPEGs. The numbers of repeating units of EO were 6, 10, 24, and 46. The chemical structure and mole ratio of the monomers was determined by Fourier transform infrared (FTIR), ¹H‐NMR, and ¹³C‐NMR spectroscopy. The d‐spacing increased with the number of EO and the values of the copolymers were in the range of 0.437–0.452 nm. The lower critical solution temperature of the poly(NIPAM‐co‐MPEG) shifted to higher temperature as the number of EO and the amount of MPEG increased. The change of chemical shift for methoxy proton in MPEG exhibited a larger than those of the other protons of the poly(NIPAM‐co10?2MPEG). Activation energy (E_a) for methoxy proton in MPEG showed a larger value than that of the methyl proton in NIPAM. These NMR results indicate the fact that more significant conformational transformations occur in the methoxy group through the phase separation than in the methyl group in NIPAM. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1833–1841, 2006     

Synthesis and characterization of a novel stimuli‐responsive magnetite nanohydrogel based on poly(ethylene glycol) and poly(N‐isopropylacrylamide) as drug carrier

A novel stimuli‐responsive magnetite nanohydrogel (MNHG), namely [poly(ethylene glycol)‐block‐poly(N‐isopropylacrylamide‐co‐maleic anhydride)₂]‐graft‐poly(ethylene glycol)/Fe₃O₄ [PEG‐b‐(PNIPAAm‐co‐PMA)₂]‐g‐PEG/Fe₃O₄, was successfully developed. For this purpose, NIPAAm and MA monomers were block copolymerized onto PEG‐based macroinitiator through atom transfer radical polymerization technique to produce PEG‐b‐(PNIPAAm‐co‐PMA)₂. The synthesized Y‐shaped terpolymer was crosslinked through the esterification of maleic anhydride units using PEG chains to afford a hydrogel. Afterward, magnetite nanoparticles were incorporated into the synthesized hydrogel through the physical interactions. The chemical structures of all synthesized samples were characterized using Fourier transform infrared and proton nuclear magnetic resonance spectroscopies. Morphology, thermal stability, size, and magnetic properties of the synthesized MNHG were investigated. In addition, the doxorubicin hydrochloride loading and encapsulation efficiencies as well as stimuli‐responsive drug release ability of the synthesized MNHG were also evaluated. The drug‐loaded MNHG at physiological condition exhibited negligible drug release values. In contrast, at acidic (pH 5.3) condition and a little bit higher temperature (41 °C) the developed MNHG showed higher drug release values, which qualified it for cancer chemotherapy due to especial physiology of cancerous tissue in comparison with the surrounding normal tissue. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46657.     

Poly(HEMA)/cyclodextrin‐based hydrogels for subconjunctival delivery of cyclosporin A

To enhance the solubility and ocular permeability of immunosuppressive agent, cyclosporine A (CsA), three types of delivery systems were prepared using (2‐hydroxypropyl)‐β‐cyclodextrin (HPβCD), and 2‐hydroxyethyl methacrylate (HEMA). Those systems are (i) hydrogels of HPβCD with crosslinking agent ethylene glycol diglycidylether, (ii) poly(HEMA) hydrogels, and (iii) different amounts of HPβCD‐containing poly(HEMA) hydrogels indicated as poly(HEMA‐co‐HPβCD). In the presence of HEMA, hydrogels have desired mechanical integrity with lower equilibrium content than that of hydrogels without HEMA. CsA was loaded into the HPβCD‐based hydrogels by embedding from its aqueous suspensions in higher amounts than that of the poly(HEMA) hydrogels that were loaded by CsA–HPβCD complex solution. Although the poly(HEMA) hydrogels are releasing total CsA in 3 days, long‐term release was realized from HPβCD‐based hydrogels. For subconjunctival administration, regarding to the amounts of loaded CsA, release profiles, and mechanical integrity, the most suitable system is poly(HEMA‐co‐HPβCD) hydrogels in high HPβCD content. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40397.     

Effects of the process parameters on the initial burst release of poly(lactide‐co‐glycolide) microspheres containing bovine serum albumin by the double‐emulsion solvent evaporation/extraction method

The effects of fabrication parameters on the morphology, drug loading, and initial burst release of poly(lactide‐co‐glycolide) microspheres loaded with bovine serum albumin were investigated to establish an optimal process and system for the in vivo delivery of therapeutic proteins. Through the addition of salts or sugars to induce an osmotic pressure in the external water phase, large microspheres were seen to have their morphology, drug loading, and initial burst release significantly affected. However, the effect was not observed for compact microspheres less than 10 μm in diameter. The presence of poly(vinyl alcohol), Pluronic F127, and Tween 80 in the internal water phase had detrimental effects on the drug loading because of the depressed stability of the primary emulsion and competitive interactions of surface‐active substances with the polymer. However, the simultaneous addition of salts to the external water phase resulted in enhanced drug loading and decreased initial burst. The polymer concentration and volume of the internal water phase were important factors influencing the characteristics of the microspheres. These parameters were optimized for achieving the maximal drug loading and a low initial burst. The solvent extraction method yielded microspheres with a higher drug loading and a lower initial burst in comparison with the solvent evaporation method. Different ranges of protein encapsulation efficiencies were obtained with blends of poly(lactide‐co‐glycolide) and poly(ethylene glycol), depending on the molecular weight and content of poly(ethylene glycol). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Encapsulation of curcumin by methoxy poly(ethylene glycol‐b‐aromatic anhydride) micelles

Suitable carrier systems for sustained release of curcumin were studied by using the self‐assembled polymeric micelles. Poly(ethylene glycol) methyl ether and poly(aromatic anhydride) were used as the hydrophilic and hydrophobic blocks, respectively, in forming amphiphilic diblock copolymers. Four different types of polymers methoxy poly(ethylene glycol‐ b‐1,3‐bis(p‐carboxyphenoxy)propane) (mPEG₅₀₀₀CPP, mPEG₂₀₀₀CPP), methoxy poly(ethylene glycol‐b‐1,6‐bis(p‐carboxyphenoxy)hexane) (mPEG₅₀₀₀CPH, mPEG₂₀₀₀CPH) were synthesized via melt condensation approach. Micelles were formed at very low polymer concentration with stable hydrophobic cores. The particle sizes of micelles remained stable during degradation period. All four different polymeric micelles showed low cytotoxicity toward human fibroblasts cells and can kill cancer cells in very low concentrations. High loading efficiency and drug content were observed in curcumin‐loaded micelles. Curcumin showed mild initial burst (30% of drug loading in the first 24 h) when released from the micelles and its release was sustained for at least 18 days. These micelles, especially those of mPEG₅₀₀₀CPP, show potential to serve as the delivery vehicles for sustained release of curcumin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

Poly(methyl methacrylate)/poly(ethylene glycol)/poly(ethylene glycol dimethacrylate) micelles: Preparation,characterization, and application as doxorubicin carriers

A crosslinked amphiphilic copolymer [poly(ethylene glycol) (PEG)–poly(methyl methacrylate) (PMMA)–ethylene glycol dimethacrylate (EGDM)] composed of PMMA, PEG, and crosslinking units (EGDM) was synthesized by atom transfer radical polymerization to develop micelles as carriers for hydrophobic drugs. By adjusting the molar ratio of methyl methacrylate and EGDM, three block copolymer samples (P0, P1, and P2) were prepared. The measurement of gel permeation chromatography and ¹H‐NMR indicated the formation of crosslinked structures for P1 and P2. Fluorescence spectroscopy measurement indicated that PEG–PMMA–EGDM could self‐assemble to form micelles, and the critical micelle concentration values of the crosslinked polymer were lower than those of linear ones. The prepared PEG–PMMA–EGDM micelles were used to load doxorubicin (DOX). The drug‐loading efficiencies of P1 and P2 were higher than that of P0 because the crosslinking units enhanced the micelles' stability. With increasing drug‐loading contents, DOX release from the micelles in vitro was decreased, and in the crosslinked formulations, the release rate was also slower. An in vitro release study indicated that DOX release from the micelles for the linear samples was faster than that for crosslinked micelles. The drug feeding amount increased and resulted in an increase in the drug‐loading content, and the loading efficiency decreased. These PEG–PMMA–EGDM micelles did not show toxicity in vitro and could reduce the cytotoxicity of DOX in the micelles; this suggested that they are good candidates as stable drug carriers. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39623.     

Injectable and thermosensitive poly(organophosphazene) hydrogels for a 5‐fluorouracil delivery

The drug solubility and its release profiles of an anticancer drug from an injectable thermosensitive poly(organophosphazene) hydrogel bearing hydrophobic L ‐isoleucine ethyl ester and hydrophilic α‐amino‐ω‐methoxy‐poly(ethylene glycol) with and without hydrolysis‐sensitive glycyl lactate ethyl ester or functional glycyl glycine have been investigated. 5‐Fluorouracil (5‐FU) was used as a model anticancer drug. The aqueous solutions of 5‐FU incorporated poly(organophosphazenes) were an injectable fluid state at room temperature and formed a transparent gel at body temperature. The poly(organophosphazene) solution could enhance the solubility of 5‐FU and its solubility (34.26 mg/mL) was increased up to 10‐fold compared to that in phosphate‐buffered saline (3.39 mg/mL, pH 7.4, 4°C). The in vitro drug release profiles from poly(organophosphazene) hydrogels were established in phosphate‐buffered saline at pH 7.4 at 37°C and the release of 5‐FU was significantly affected by the diffusion‐controlled stage. The results suggest that the injectable and thermosensitive poly(organophosphazene) hydrogel is a potential carrier for 5‐FU to increase its solubility, control a relatively sustained and localized release at target sites and thus decrease systemic side effects. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Acrylate/EVA reactive blends and semi‐IPN: Chemical,chemical–physical,and thermo‐optical characterization

In the present work, blends between poly(methyl methacrylate) (PMMA) or its copolymer with butyl methacrylate P(MMA‐co‐BMA) and poly(ethylene‐co‐vinyl acetate) (EVA) rubbers obtained applying the reactive blending principles were deeply investigated to clarify the chemistry of the system. A copolymeric phase, which is created in situ, was isolated and its chemical structure was determined through NMR analysis. The blends were also crosslinked with a flexible dimethacrylate to realize semi‐interpenetrated networks. The blends were characterized for their properties of interest (mechanical and optical behaviors). Particularly, an accurate investigation of the optical properties as a function of the temperature was performed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Novel thermosensitive hydrogel composites based on poly(d,l‐lactide‐co‐glycolide) nanoparticles embedded in poly(n‐isopropyl acrylamide) with sustained drug‐release behavior

To reach sustained drug release, a new composite drug‐delivery system consisting of poly(d,l ‐lactide‐co‐glycolide) (PLGA) nanoparticles (NPs) embedded in thermosensitive poly(N‐isopropyl acrylamide) (PNIPAAm) hydrogels was developed. The PNIPAAm hydrogels were synthesized by free‐radical polymerization and were crosslinked with poly(ethylene glycol) diacrylate, and the PLGA NPs were prepared by a water‐in‐oil‐in‐water double‐emulsion solvent‐evaporation method. The release behavior of the composite hydrogels loaded with albumin–fluorescein isothiocyanate conjugate was studied and compared with that of the drug‐loaded neat hydrogel and PLGA NPs. The results indicate that we could best control the release rate of the drug by loading it to the PLGA NPs and then embedding the whole system in the PNIPAAm hydrogels. The developed composite hydrogel systems showed near zero‐order drug‐release kinetics along with a reduction or omission of initial burst release. The differential scanning calorimetry results reveal that the lower critical solution temperature of the developed composite systems remained almost unchanged (<1°C increase only). Such a characteristic indicated that the thermosensitivity of the PNIPAAm hydrogel was not distinctively affected by the addition of PLGA NPs. In conclusion, an approach was demonstrated for the successful preparation of a new hybrid hydrogel system having improved drug‐release behavior with retained thermosensitivity. The developed systems have enormous potential for many biotechnological applications. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40625.     

Hollow poly(N‐isopropylacrylamide)‐co‐poly(acrylic acid) microgels with high loading capacity for drugs

A convenient approach has been developed for the preparation of microsize hydrogels composed of crosslinked poly(acrylic acid) (PAA) and poly(N‐isopropylacrylamide) (PNIPAm). First, semi‐interpenetration polymer networks of hydropropylcellulose (HPC) and PNIPAm‐co‐PAA copolymer are formed through the copolymerization and crosslinking of monomer acrylic acid and N‐isopropylacrylamide in HPC aqueous solution. After the selective removal of HPC from networks due to ionization of PAA units and disruption of hydrogen bonding with increasing pH, PNIPAm‐co‐PAA microgels are obtained, whose volume is confirmed to be responsive to both temperature and pH. Doxorubicin hydrochloride (Dox) can be encapsulated in PNIPAm‐co‐PAA microgels with high drug loading driven by the electrostatic interaction, and a sustained‐release characteristic of Dox from the microgels is observed under physiological pH value and temperature. In vitro cell experiments, the drug‐loaded microgels can be taken up by LoVo cells and release their payload in cell cytoplasm without loss of drug efficacy. This indicates that PNIPAm‐co‐PAA microgels might be a potential drug delivery carriers especially for water‐soluble or polypeptide drugs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

A facile preparation of pH‐temperature dual stimuli‐responsive supramolecular hydrogel and its controllable drug release

A series of pH‐temperature dual stimuli‐responsive random copolymers poly[N,N‐dimethylaminoethyl methacrylate‐co‐poly(poly(ethylene glycol) methyl ether methacrylate][poly(DMAEMA‐co‐MPEGMA)] were synthesized by free radical polymerization. The supramolecular hydrogel was formed by pseudopolyrotaxane, which was prepared with the host‐guest interactions between α‐cyclodextrin (α‐CD) and poly(ethylene glycol) (PEG) side chains. Fourier transform infrared (FT‐IR), nuclear magnetic resonance (¹H NMR), and X‐ray diffraction (XRD) confirmed the structures of the hydrogels. The pH‐temperature dual stimuli responsive properties of the hydrogels were characterized by rheometer. Finally, the controllable drug release behavior of the hydrogel, which was used 5‐fluorouracil (5‐Fu) as the model drug, was investigated at different temperatures and different pH values. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43279.     

Modification of porous suspension‐PVC particles by stabilizer‐free aqueous dispersion polymerization of absorbed monomers

The modification of porous PVC particles by an in‐situ stabilizer‐free polymerization/crosslinking of a monomer/crosslinker/peroxide solution absorbed within the PVC particles is presented. The modifying crosslinked polymers are polystyrene (PS) crosslinked with DVB (divinyl benzene), polymethyl methacrylate (PMMA) crosslinked with ethylene glycol dimethacrylate (EGDMA), and styrene‐MMA copolymer crosslinked with DVB. The modified PVC particles characterization includes polymerization yield, non‐extractables, ¹³C solid‐state CPMAS NMR, porosity measurements and also morphology and dynamic mechanical behavior (DMTA). The levels of nonextractable fractions found and ¹³C solid‐state CPMAS NMR results are indicative of low chemical interaction in the semi‐IPN PVC particles. Particle porosity levels and SEM observations indicate that styrene and MMA mainly polymerize within the PVC particles' bulk and just small amounts in the pores. MMA polymerization in the PVC pores is as crusts covering the PVC pore surfaces, whereas styrene polymerization in the PVC pores is by filling the pores. Dynamic mechanical studies show that tanδ and the storage modulus curves are influenced by the incorporation of PS and XPS but not by the incorporation of PMMA and XPMMA.     

Synthesis of block copolymers via redox polymerization

Polymerization and copolymerization of vinyl monomers such as acrylamide, acrylonitrile, vinyl acetate, and acrylic acid with a redox system of Ce(IV) and organic reducing agents containing hydroxy groups were studied. The reducing compounds were poly(ethylene glycol)s, halogen‐containing polyols, and depolymerization products of poly(ethylene terephthalate). Copolymers of poly(ethylene glycol)s‐b‐polyacrylonitrile, poly(ethylene glycol)s‐b‐poly(acrylonitrile‐co‐vinyl acetate), poly(ethylene glycol)s‐b‐polyacrylamide, poly(ethylene glycol)s‐b‐poly(acrylamide‐co‐vinyl acetate), poly(1‐chloromethyl ethylene glycol)‐bpoly(acrylonitrile‐co‐vinyl acetate), and bis[poly(ethylene glycol terephthalate)]‐b‐poly(acrylonitrile‐co‐vinyl acetate) were produced. The yield of acrylamide polymerization and the molecular weight of the copolymer increased considerably if about 4% vinyl acetate was added into the acrylamide monomer. However, the molecular weight of the copolymer was decreased when 4% vinyl acetate was added into the acrylonitrile monomer. Physical properties such as solubility, water absorption, resistance to UV light, and viscosities of the copolymers were studied and their possible uses are discussed. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1385–1395, 1999     

Synthesis and characterization of a porous poly(hydroxyethylmethacrylate‐co‐ethylene glycol dimethacrylate)‐based hydrogel device for the implantable delivery of insulin

Poly(hydroxyethylmethacrylate‐co‐ethylene glycol dimethacrylate) [poly(HEMA‐co‐EGDMA)]‐based hydrogel devices were synthesized by a free‐radical polymerization reaction with 2‐hydroxyethylmethacrylate as the monomer, different concentrations of ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent, and ammonium persulfate/N,N,N′,N′‐tetra‐methyl ethylenediamine as the free‐radical initiator. The porosity of the poly(HEMA‐co‐EGDMA) hydrogels was controlled with water as the porogen. The Fourier transform infrared spectrum of poly(HEMA‐co‐EGDMA) showed absorption bands associated with ? C?O stretching at 1714 cm^?1, C? O? C stretching vibrations at 1152 cm^?1, and a broad band at 3500–3800 cm^?1 corresponding to ? OH stretching. Atomic force microscopy studies showed that the hydrogel containing 67% water had pores in the range of 3500–9000 nm, whereas the hydrogel containing 7% water did not show measurable pores. The hydrogel synthesized with 1% EGDMA showed 50% thallium‐201 release within the first 30 min and about 80% release within 60 min. In vitro insulin‐release studies suggested that the hydrogel with 27% water showed sustained release up to 120 min, whereas the hydrogels with 47 and 67% water showed that nearly all of the insulin was released within 60 min. Hydrogel devices synthesized with 27% water and filled with insulin particles showed sustained release for up to 8 days, whereas the hydrogels synthesized with 47 and 67% water released insulin completely within 3 days of administration. Animal studies suggested that the hydrogel devices synthesized with 27% water and filled with insulin‐loaded particles (120 IU) were able to control blood glucose levels for up to 5 days after implantation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Polycarbonate microspheres containing tumor necrosis factor‐α genes and magnetic powder as potential cancer therapeutics

Amphiphilic polycarbonate copolymers including methoxy‐terminated poly(ethylene glycol)‐co‐poly (5,5‐dimethyl trimethylene carbonate) [Poly(PEG‐b‐TMC)] and poly(ethylene glycol)‐co‐poly(trimethylene carbonate) [Poly(PEG‐b‐DTC)] were synthesized. The water‐in‐oil‐in‐water (W/O/W) solvent evaporation technique was adopted to produce anticancer magnetic Poly(PEG‐b‐DTC) microspheres containing tumor necrosis factor‐α (TNF‐α) genes and Fe₃O₄ magnetic ultrafine powder. Drug release studies showed that the microspheres can sustain a steady release rate of TNF‐α genes in 0.1M phosphate buffer saline solution in vitro for up to 60 h. In vitro cytotoxicity assays demonstrated that the microspheres have high inhibition and antitumor action to human hepatocellular carcinoma (Bel‐7204) cells in vitro. In vivo inhibition on the growth of hepatic carcinomas and histopathologic observation indicated that the microspheres possess a markedly high antitumor activity to human hepatocellular carcinoma (Bel‐7204). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and thermal properties of poly(acrylonitrile‐co‐allyl glycidyl ether)‐graft‐methoxypoly(ethylene glycol) copolymers as novel solid–solid phase‐change materials for thermal energy storage

We synthesized a series of poly(acrylonitrile‐co‐allyl glycidyl ether)‐graft‐methoxypoly(ethylene glycol) (PAA‐g‐MPEG) copolymers as novel polymeric solid–solid phase‐change materials by grafting methoxypoly(ethylene glycol) (MPEG) to the main chain of poly(acrylonitrile‐co‐allyl glycidyl ether) (PAA). PAA was the skeleton, and MPEG was a functional side chain, which stored and released heat during its phase‐transition process. Fourier transform infrared spectroscopy and ¹H‐NMR spectroscopy analysis were performed to investigate the chemical structures. The crystalline morphology and crystal structures were also measured with polarized optical microscopy and X‐ray diffraction. Moreover, the thermal‐energy‐storage properties, thermal stability, and thermal reliability of the PAA‐g‐MPEG copolymers were characterized by differential scanning calorimetry and thermogravimetric analysis (TGA) methods. These analysis results indicate that the MPEG chains were successfully grafted onto PAA, and we found that the PAA‐g‐MPEG copolymers had typical solid–solid phase‐transition temperatures in the range 11–54 °C and high latent heat enthalpies between 44 and 85 J/g. In addition, the as‐prepared PAA‐g‐MPEG copolymers showed reusability and thermal reliability, as shown by the thermal cycle testing and TGA curves. Therefore, the synthesized PAA‐g‐MPEG copolymers have considerable potential for thermal energy storage. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46641.     

Cationic copolymerization behavior of a bicyclic orthoester having hydroxy group with glycidyl phenyl ether and volume change on their copolymerization

This article describes cationic ring‐opening copolymerization of a bicyclic orthoester having hydroxy group (BOE‐OH) and glycidyl phenyl ether (GPE), and the volume shrinkage behavior during the copolymerization. THF soluble polyethers [poly(BOE‐OH‐co‐GPE)] were obtained by the copolymerizations at 80–180°C, while crosslinked poly(BOE‐OH‐co‐GPE) was obtained by the copolymerizations at 220–250°C. This crosslinking reaction may originate from the dehydration of methylol groups in the side chain of poly(BOE‐OH‐co‐GPE). The volume shrinkage during the cationic copolymerization reduced as the increase of the BOE‐OH feed ratio. By contrast, the volume shrinkage on the crosslinking polymerization was almost independent on the BOE‐OH feed ratio. Poly(BOE‐OH‐co‐GPE)s with higher BOE‐OH composition showed lower thermal weight loss temperature owing to the release of H₂O by dehydration of methylol groups. The BOE‐OH component in the THF soluble poly(BOE‐OH‐co‐GPE)s lowered the glass transition temperature (T_g), while that in the crosslinked poly(BOE‐OH‐co‐GPE) increased the T_g probably because of the higher crosslinking density. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 1356–1361, 2006     

Synthesis and characterization of binary copolymers of methyl methacrylate with glycidyl methacrylate and 2‐hydroxy ethyl methacrylate as carriers for cellulase

Cellulase was immobilized directly on methyl methacrylate‐glycidyl methacrylate copolymer (MMA‐co‐GMA) and methyl methacrylate‐2‐hydroxy ethyl methacrylate copolymer (MMA‐co‐HEMA) by covalent attachment and crosslinking methods. The properties of the immobilized cellulase were investigated and compared with those of the free one. For the assays carried out through crosslinking method at 25°C and pH 7, the retained activities were found to be 91.92% and 74.63%, respectively, for MMA‐co‐GMA and MMA‐co‐HEMA crosslinked with 0.1% of 1‐cyclohexyl‐3‐(2‐morpholino‐ethyl) carbodiimide metho‐p‐toluenesulfonate (CMCT), respectively. The immobilized cellulase had better stability and higher retained activities with respect to pH, temperature, and storage stability than the free one. In the repeated use experiments, the immobilized cellulase using (MMA‐co‐GMA)‐CMCT (0.1%) and (MMA‐co‐HEMA)‐CMCT (0.1%) did not change after 10 and eight times of repeated use and maintained 67% and 62% from their original activities after 25 times, respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Effect of methyl methacrylate on the properties of transparent flame retardant unsaturated phosphate ester copolymer

The effect of methyl methacrylate (MMA) on the properties of transparent flame retardant unsaturated phosphate ester copolymer (poly[UPE‐co‐MMA]) prepared by bulk polymerization technique was investigated. Fourier transform infrared spectra, gel fraction (G) test, and dynamic mechanical analysis revealed the structure and crosslinking density of poly(UPE‐co‐MMA) copolymers. The thermal degradation and flame retardancy of copolymers were indicated by thermogravimetric analysis, limiting oxygen index (LOI), and microscale combustion calorimeter (MCC) test. Besides, the mechanical properties and transparency were tested with testing machines and solid ultraviolet absorption spectra. As the MMA content increased to 50%, the copolymer contained 50 wt% MMA showed the maximal G (88.93%) and transmittance was up to 91.72%. From the poly(UPE‐co‐MMA) copolymers, the tensile strength increased from 14.62 to 26.95 MPa, assigned to the increase of crosslinking density of copolymers. The char yield of poly(UPE‐co‐MMA) was up to 21.18 wt%, which was a result of decomposition of phosphate groups, producing a phosphorus‐rich layer that increased the thermal stability of the residues. LOI and MCC results confirm that the introduction of MMA can retain the flame retardancy of copolymer remarkably. POLYM. ENG. SCI., 59:2103–2109, 2019. © 2019 Society of Plastics Engineers