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     

Synthesis and characterization of emulsion copolymer of N‐cyclohexylmaleimide and methyl methacrylate

Copolymers of N‐cyclohexylmaleimide (ChMI) and methyl methacrylate (MMA) were synthesized by the emulsion semibatch copolymerization method. The effects of the monomer mixture composition on the average molecular weight (M_n and M_w ), glass transition temperature (T_g), degradation temperature, mechanical properties, and rheological behavior of the copolymers were investigated. The results show that M_n and M_w have maximum values when the ChMI feed content was about 20% (by wt). The degradation temperature and T_g of the copolymers increase with increasing ChMI moieties in the copolymer. The mechanical properties (tensile strength and impact strength) decrease with an increasing ChMI feed content. All copolymers in the melt show pseudoplastic behavior. The flow index n increases with an increasing ChMI feed content. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1070–1075, 2002; DOI 10.1002/app.10394     

Kinetics for copolymerization of methyl methacrylate with N‐cyclohexylmaleimide

The kinetics for the radical copolymerization of methyl methacrylate (MMA) with N‐cyclohexylmaleimide (NCMI) was investigated. The initial copolymerization rate R_p is proportional to the initiator concentration to the power of 0.54. The apparent activation energy of the overall copolymerization was measured to be 69.0 kJ/mol. The monomer reactivity ratios were determined to be r_NCMI = 0.42 and r_MMA = 1.63. R_p reduces slightly, and the molecular weight of the resultant copolymer decreases with increasing the concentration of the chain transfer agent N‐dodecanethiol (RSH). The more the transfer agent, the narrower the molecular weight distribution of the resulting copolymer. The following chain‐transfer constant of RSH for the copolymerization of MMA with NCMI in benzene at 50°C was obtained: C_s = 0.23. The glass transition temperature (T_g) of the copolymer increases with increasing f_NCMI, which indicates that adding NCMI can improve the heat resistance of Plexiglas. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1293–1297, 1999     

Blends of poly(vinyl chloride) (PVC)/natural rubber‐g‐(styrene‐co‐methyl methacrylate) for improved impact resistance of PVC

To improve the mechanical properties of poly(vinyl chloride) (PVC), the possibility of combining PVC with elastomers was considered. Modification of natural rubber (NR) by graft copolymerization with methyl methacrylate (MMA) and styrene (St) was carried out by emulsion polymerization by using redox initiator to provide an impact modifier for PVC. The impact resistance, dynamic mechanical analysis (DMA), and scanning electron microscopy (SEM) of St and MMA grafted NR [NR‐g‐(St‐co‐MMA)]/PVC (graft copolymer product contents of 5, 10, and 15%) blends were investigated as a function of the amount of graft copolymer product. It was found that the impact strength of blends was increased with an increase of the graft copolymer product content. DMA studies showed that NR‐g‐(St‐co‐MMA) has partial compatibility with PVC. SEM confirmed a shift from brittle failure to ductility with an increase graft copolymer content in the blends. The mechanical properties showed that NR‐g‐(St‐co‐MMA) interacts well with PVC and can also be used as an impact modifier for PVC. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1666–1672, 2004     

Bulk and solution copolymerization of methyl methacrylate and vinyl acetate

A series of batch, bulk and solution (in toluene) copolymerizations of methyl methacrylate and vinyl acetate was performed under various reaction conditions to high monomer conversions. In addition, low conversion bulk experiments were performed to estimate monomer reactivity ratios using the error in variables model method, based on terminal model (Mayo–Lewis) kinetics. A combination of the low and high conversion data with data from a previous study yielded reactivity ratio (r) estimates of 27.465 and 0.0102 for r_MMA and r_VAc, respectively, using the integrated copolymer composition (Meyer–Lowry) equation. In the high conversion experiments the effects of various factors on the reaction rate, cumulative copolymer composition, number‐ and weight‐average molecular weights, and molecular weight distribution were studied. The factors included the monomer feed composition, initiator concentration, temperature, solvent concentration, and the addition of n‐dodecyl mercaptan chain transfer agent. These factors were examined in light of the wide difference in the monomer reactivity ratios. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 1238–1255, 2001     

Graft‐modified HCPE with methyl methacrylate by the mechanochemistry reaction. II. Physical‐mechanical properties and processability

In this article, the physical‐mechanical properties and processability of graft‐modified highly chlorinated polyethylene (HCPE; chlorine contents: ≥ 60%) with methyl methacrylate (MMA) by mechanochemistry reaction were studied. The results showed that the HCPE‐g‐MMA system is superior to unmodified HCPE in physical‐mechanical properties, particularly in processability. In addition, the HCPE‐g‐MMA system, with about 62% chlorine content, was the same as PVC in its physical‐mechanical properties. The HCPE‐g‐MMA system, with about 65.5% chlorine content, is the same as chlorinated poly(vinyl chloride) (CPVC) in its physical‐mechanical properties, except that the Vicat softening temperature and processability of HCPE‐g‐MMA system are superior to PVC and CPVC. Compared with PVC and CPVC, the HCPE‐g‐MMA system proves better due to its lack of a toxic monomer. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 282–287, 2004     

UV‐radiation induced graft copolymerization of methyl methacrylate onto sodium salt of partially carboxymethylated psyllium

UV‐radiation induced grafting of methyl methacrylate onto sodium salt of partially carboxymethylated psyllium has been carried out using ceric ammonium nitrate as a photoinitiator in an aqueous medium. The reaction variables including concentrations of initiator, nitric acid, monomer, and amount of the backbone as well as time and temperature have been varied for establishing the optimized reaction conditions for grafting. The influence of these reaction conditions on the grafting yields has been discussed. The overall activation energy of grafting has been calculated. The infrared spectroscopic, thermogravimetric analysis, and scanning electron microscopic techniques have been used for the characterization of graft copolymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Free‐radical copolymerization and kinetic treatment of methyl methacrylate with N‐P‐tolylmaleimide

The free‐radical copolymerization of methyl methacrylate (MMA) with N‐P‐tolylmalemide (NPTMI) at 77°C in cyclohexanone solution initiated by AIBN was studied. The copolymer composition was calculated from the nitrogen content estimated by the Mico–Kijedldahl's method and by elemental analysis. The reactivity ratios have been calculated by Fineman and Ross method. The monomer reactivity ratios were r_NPTMI = 1.24, r_MMA = 2.1. The glass transition temperature (T_g) of the copolymers were determined by torsion braid analysis (TBA). The thermal stability was determined by thermogravimetric analysis (TGA). T₅₀, temperature at which the weight loss reaches 50%, was abstained. The results showed that the M _n and M _w increased, whereas the NPTMI feed content increased. The T_g and T₅₀ increased dramatically. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 867–870, 2004     

Synthesis and characterization of epoxy resin modified with γ‐thiopropyl triethoxy silane

Organic/inorganic hybrids with 1 to 7% silica contents were synthesized from bisphenol‐A and epichlorohydrin by utilizing γ‐thiopropyl triethoxy silane (KH580). The reactive coupling agent KH580 was introduced to epoxy resin to obtain high adhesive strength material for engineering industry. It was hypothesized that the multiple reactive functional silanol group Si? OH of KH580 after hydrolyzing reacted with epoxy resin to increase the shear strength and toughness of epoxy resin. IR spectra indicated that bonded stationary phase was formed. Shear strength of epoxy resin–based composite increased and then decreased after SiO₂ content reached 5 wt %; the optimal value was 24.78 MPa. SEM analysis showed that toughness of SiO₂/epoxy resin–based composite also increased and then decreased when the content of SiO₂ is more than 5 wt %. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Radiation‐induced graft copolymerization of MMA monomer onto UHMWPE: Adhesion improvement

Graft copolymerization of methyl methacrylate monomer onto ultra high molecular weight polyethylene (UHMWPE) and acid‐etched UHMWPE was conducted using preirradiation method in air in the presence of a Mohr salt and sulfuric acid to improve adhesion to the bone cement. The grafted samples were characterized by Fourier transform infrared (FTIR) spectroscopy, gravimetric method, goniometry, and interfacial bonding strength measurements. The FTIR results showed the presence of ether, carbonyl, and hydroxyl groups for grafted films. The gravimetric results showed that the chromic acid etching and graft copolymerization had a synergetic effect so, the irradiated, then chromic acid etched at room temperature and grafted sample (Rad etch25) had the highest grafting degree. The interfacial bonding strength between UHMWPE and poly methyl methacrylate bone cement was considerably improved by graft copolymerization and chromic acid etching. The surface morphology was studied by scanning electron microscopy. The substitution of polar groups into the backbone of UHMWPE by chromic acid etching and graft copolymerization changed its contact angles with water and methylene iodide and increased its surface energy, as evidenced by contact angle measurements. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Atom transfer radical copolymerization of methyl methacrylate with N‐cyclohexylmaleimide

Atom transfer radical polymerization has been applied to simultaneously copolymerize methyl methacrylate (MMA) and N‐cyclohexylmaleimide (NCMI). Molecular weight behaviour and kinetic study on the copolymerization with the CuBr/bipyridine(bpy) catalyst system in anisole indicate that MMA/NCMI copolymerization behaves in a ‘living’ fashion. The influence of several factors, such as temperature, solvent, initiator and monomer ratio, on the copolymerization were investigated. Copolymerization of MMA and NCMI in the presence of CuBr/bpy using cyclohexanone as a solvent instead of anisole displayed poor control. The monomer reactivity ratios were evaluated as r_NCMI = 0.26 and r_MMA=1.35. The glass transition temperature of the resulting copolymer increases with increasing NCMI concentration. The thermal stability of plexiglass could be improved through copolymerization with NCMI. © 2000 Society of Chemical Industry     

Improvement of mechanical stability of beechwood by radiation‐induced in situ copolymerization of allyl glycidyl ether with acrylonitrile and methyl methacrylate

Acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether (AGE), AGE + AN monomer, AGE + MMA monomer, and monomer mixtures were used to conserve and consolidate beechwood. After the impregnation of these monomer mixtures in the wood, polymerization was accomplished by gamma irradiation. The fine structures of wood + polymer(copolymer) composites were investigated by scanning electron microscopy (SEM). The copolymer obtained from AGE + MMA monomer mixtures showed the optimum compatibility with the wood. The compressive strength and Brinell hardness numbers determined for untreated and treated wood samples indicated that the mechanical strength was greater in wood + polymer(copolymer) composites than in untreated wood and was greatest in the samples containing AGE + AN and AGE + MMA copolymers. All monomer couples used in this study increased the mechanical strength of the wood and protected the samples against aging. AGE + MMA copolymers were the most effective in protecting the wood against various environmental attacks. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1515–1523, 1999     

Radical copolymerization between methyl methacrylate and N‐cyclohexylmaleimide with thiol as an inifer

N‐dodecanethiol (RSH) was found efficient to initiate the radical copolymerization of methyl methacrylate (MMA) with N‐cyclohexylmaleimide (NCMI) at 40–60°C. The initial copolymerization rate, R_p, increases respectively with increasing [RSH] and the mol fraction of NCMI in the comonomer feed, f_NCMI. The molecular weight of the copolymer decreases with increasing [RSH]. The initiator transfer constant of RSH was determined to be C_I = 0.21. The apparent activation energy of the overall copolymerization was measured to be 46.9 kJ/mol. The monomer reactivity ratios were determined to be r_NCMI = 0.32 and r_MMA = 1.35. The glass transition temperature of the copolymer increases obviously with increasing f_NCMI, which indicates that adding NCMI may improve the heat resistance of plexiglass. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 1417–1423, 1999     

Surface modification of natural rubber film by UV‐induced graft copolymerization with methyl methacrylate

Methyl methacrylate (MMA) was directly grafted on natural rubber (NR) or sulfur prevulcanized (SP) NR surface. The rubber sheet was primarily treated with argon plasma, followed by exposure to air for generating active functional groups. After immersing in a mixture of 30% hydrogen peroxide and MMA in ethanol and water (1 : 1), the MMA grafting took place after UV‐irradiation for 30–120 min. Results from the contact angle measurement and attenuated total reflection–Fourier transform infrared (ATR‐FTIR) spectroscopy showed that the highest amount of MMA grafting was achieved when using 13 wt % of MMA and UV irradiation time of 60 min. The tensile strength and percentage elongation at break of the modified SPNR sheet, having similar MMA grafting to that of NR, were in acceptable range as indicated in the standard glove's test (ASTM D3577). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 2270–2276, 2007     

Synthesis and characterization of N‐acryloylcarbazole/methyl methacrylate copolymers

Copolymers of N‐acryloylcarbazole (A) and methyl methacrylate (M) were synthesized in different in‐feed ratios. The composition of the copolymer was determined by the help of ¹H NMR spectrum. The comonomer reactivity ratios determined by Kelen‐Tudos (KT) and nonlinear error‐in‐variables methods were r_A = 1.12 ± 0.16, r_M = 0.94 ± 0.14, and r_A = 1.05, r_M = 0.90, respectively. Complete spectral assignments of the ¹H and ¹³C ¹H NMR spectra of the copolymers were done by the help of distortionless enhancement by polarization transfer (DEPT) and two‐dimensional NMR techniques, such as heteronuclear single quantum coherence (HSQC), total correlation spectroscopy (TOCSY), and heteronuclear multiple bond correlation (HMBC). The methine, α‐methyl, and carbonyl carbon resonances were found to be sequence sensitive. The signals obtained were broad because of the restricted rotation of bulky carbazole group and the quadrupolar effect of nitrogen present in carbazole moiety. Glass transition temperatures (T_g) were determined by differential scanning calorimetry and were found to be characteristic of copolymer composition. As the N‐acryloylcarbazole content increases, the T_g increases from 378.3 K for poly(methyl methacrylate) to 430.4 K for poly(N‐acryloylcarbazole). Variation in T_g with the copolymer composition were found to be in good agreement with theoretical values obtained from Johnston and Barton equations. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2667–2676, 2006     

Formation and structure of poly(methyl methacrylate) gels containing triphenyl vinyl silane

A series of Poly(methyl methacrylate) gels (PMMA) were prepared for making optical lenses by solution free radical crosslinking copolymerization of 2,2,2,‐trifluoroethyl methacrylate (TFEMA), methyl methacrylate (MMA), ethylene glycol dimethacrylate (EGDM), and triphenyl vinyl silane (TPVS) comonomer systems. They were then studied in toluene at a total monomer concentration of 5 molL^?1 and 70°C. The conversion of monomer, volume swelling ratio, weight fraction, and gel point were measured as a function of the TPVS concentration, temperature, and chain transfer agents up to the onset of macrogelation. Structural characteristics of the gels were examined by using equilibrium swelling in toluene, gel fraction, and Fourier‐transform infrared (FTIR) analysis. The morphology of the copolymers was also investigated by Scanning electron microscopy (SEM). The dilution of the monomer mixture resulted in an increase in the gel point and swelling degree and a decrease in the percentage of conversion and gel fraction. Finally, TPVS is a compatible vinyl type silicone comonomer for this system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Synthesis and characterization of poly(methyl methacrylate‐co‐maleic anhydride) copolymers and its potential as a compatibilizer for amorphous polyamide blends

Poly(methyl methacrylate‐co‐maleic anhydride) copolymers (MMA‐MA) have been synthesized by solution method, using toluene as solvent and benzoyl peroxide as initiator. The MMA‐MA copolymers were characterized by size exclusion chromatography, Fourier transforms infrared spectroscopy (FTIR), and titration. It was found that the modified polymerization procedure used in this work was more effective in controlling the molecular weight when adding different amounts of maleic anhydride (MA) than procedures previously used. In spite of the significant difference in reactivity ratios between MMA and MA, up to 50% of the MA added to the reactor was incorporated into the copolymer. The evidences for reactions of the MA groups of the MMA‐MA copolymer with the amine end groups of the amorphous polyamide (aPA) during melt blending was obtained by rheological measurements. In this work, the molecular weight and the content of MA reactive functional groups in the MMA‐MA copolymer were varied independently and its effects on the interaction with aPA were studied. It was observed that a compromise between molecular weight and the level of reactive functional group of the compatibilizer should be sought to improve the compatibilization of the polymer systems. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007