Graft copolymerization of acrylonitrile and methacrylonitrile onto gelatin by mutual irradiation method

In order to improve upon certain properties of gelatin graft copolymerization of acrylonitrile (AN) and methacrylonitrile (MAN) onto gelatin has been studied in aqueous medium using γ rays as a source of initiation. Optimum conditions for affording maximum percentage of grafting have been evaluated as a function of various reaction parameters. The grafted polyacrylonitrile (PAN) was isolated from the graft copolymer by acid hydrolysis, and the average molecular weight (M_v) of the isolated polymer has been determined viscometrically. The graft copolymers were characterized by IR spectroscopic methods and thermogravimetric analysis (TGA). Acrylonitrile was found to be more reactive than methacrylonitrile toward graft copolymerization. © 1994 John Wiley & Sons, Inc.     

Free‐radical copolymerization of [(4‐isopropyl phenyl) oxycarbonyl] methyl methacrylate with acrylonitrile and methyl methacrylate

The present investigation has been achieved in accordance with the Diels–Alder reaction (1,4 cycloaddition) to produce a new halogenated bicyclic adduct. ortho‐Bromoallylbenzoate is a new dienophile that was prepared in a pure form, and its structure was confirmed. The Diels–Alder syntheses of hexachlorocyclopentadiene and the new dienophile were studied to determine the optimum condensation reaction conditions under a temperature range of 90–160°C, reaction times of 1–8 h, and molar diene/dienophile ratios from 1:1 to 5:1 as a consequence. The optimum conditions reached were a temperature of 140°C, an initial diene/dienophile molar ratio of 3:1, and a duration time of 6 h. The maximum stoichometric yield under these optimum conditions (82.5%) was obtained. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 2331–2338, 2003     

Atom transfer radical copolymerization of glycidyl methacrylate and methyl methacrylate

Glycidyl methacrylate (GMA) and methyl methacrylate (MMA) copolymers were synthesized by atom transfer radical polymerization (ATRP). The effect of different molar fractions of GMA, ranging from 0.28 to 1.0, on the polymer polydispersity index (weight‐average molecular weight/number‐average molecular weight) as the indicator of a controlled process was investigated at 70°C, with ethyl 2‐bromoisobutyrate as an initiator and 4,4′‐dinonyl‐2,2′‐bipyridyne (dNbpy)/CuBr as a catalyst system in anisole. The monomer reactivity ratios (r values) were obtained by the application of the conventional linearization Fineman–Ross method (r_GMA = 1.24 ± 0.02 and r_MMA = 0.85 ± 0.03) and by the Mayo–Lewis method (r_GMA = 1.19 ± 0.04 and r_MMA = 0.86 ± 0.03). The molecular weights and polydispersities of the copolymers exhibited a linear increase with GMA content. The copolymer compositions were determined by ¹H‐NMR and showed a domination of syndiotactic structures. The glass‐transition temperatures (T_g) of the copolymers analyzed by differential scanning calorimetry (DSC) decreased in the range 105–65°C with increasing GMA units. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Modification of some mechanical properties of spruce by radiation induced copolymerization of acrylonitrile and methyl methacrylate with allyl glycidyl ether

In this study, spruce samples were impregnated with acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether (AGE), AGE/AN or AGE/MMA monomers and monomer mixtures. In situ polymerization (copolymerization) was achieved by gamma irradiation. The relationship between the mechanical properties of the wood‐polymer(copolymer) composites and the kind and quantity of polymers and copolymers, irradiation dose and artificial aging treatment of the wood was investigated. The fine structure of wood‐polymer(copolymer) composites was determined by Scanning Electron Microscopy. The presence of homopolymer and copolymers increased the mechanical properties of the wood. The compressive strength and Brinell Hardness Numbers, determined for untreated and treated wood samples, indicated that the mechanical strength of wood‐polymer (copolyrner) was significantly increased in the presence of P(AGE/MMA). At maximum percent conversion, the percentage increase in the compressive strength with regard to the applied force perpendicular to the fibers in spruce was 218%. After aging for 28 days, it was found that there were no significant changes in mechanical stability.     

Graft copolymerization of acrylonitrile and methyl methacrylate monomer mixtures on crumb natural rubber

Graft copolymerization of mixtures of acrylonitrile and methyl methacylate on crumb natural rubber was carried out in toluene at 60°C. The nitrogen content of the grafted copolymer was determined by elemental analysis and used to estimate the composition of the copolymer samples. It was found that the amount of acrylonitrile monomeric units incorporated into the polymer was disproportionately lower than the acylonitrile content of the feed and explanations in terms of the e‐value of the monomers and the inherent heterogenous nature of the polymerization mixture were offered. The miscibility of the natural rubber‐g‐polyacrylonitrile‐co‐poly(methyl methacrylate) with poly(vinyl chloride) was studied by viscometry, differential scanning calorimetry, and phase contrast microscopy. It was found that the natural rubber‐g‐polyacrylonitrile‐co‐poly(methyl methacrylate) formed semimiscible blends with poly(vinyl chloride). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1872–1877, 2002; DOI 10.1002/app.10474     

Radiochemical graft copolymerization of methacrylonitrile and binary mixture of methacrylonitrile with 4-vinylpyridine onto isotactic polypropylene fiber

Graft copolymerization of methacrylonitrile (MAN) and its binary mixture with 4-vinylpyridine (4-VP) onto isotactic polypropylene (IPP) fiber has been studied in aqueous medium by the preirradiation method. Optimum conditions for obtaining the maximum percentage of grafting have been evaluated. Rate of grafting (Rg) has been determined as a function of total initial monomer concentration. The graft copolymers are characterized by IR spectroscopy, by thermogravimetric analysis, and by isolating the polymer from the graft copolymer. The effect of MAN, an acceptor monomer, on percentage of grafting of 4-VP, a donor monomer, has been discussed in the light of the mechanism proposed for grafting by the radiochemical method. © 1994 John Wiley & Sons, Inc.     

Synthesis and group transfer polymerization and copolymerization of p-vinylbenzyl methacrylate

Summary p-Vinylbenzyl methacrylate was synthesized by the phase transfer catalyzed esterification of potassium methacrylate with p-chloromethylstyrene. p-Vinylbenzyl methacrylate was homopolymerized and copolymerized with methyl methacrylate by group transfer polymerization through the methacryloyl group, resulting in reactive polymethacrylates containing pendant styrene groups.     

Efficiency of ligands in atom transfer radical polymerization of lauryl methacrylate and block copolymerization with methyl methacrylate

Atom transfer radical polymerization of lauryl methacrylate (LMA) was carried out in the presence of various ligands using ethyl-2-bromoisobutyrate as initiator and CuBr as catalyst in toluene at 95 °C. The ligands used were 2,2′-bipyridyl,4,4′-dimethyl-2,2′-bipyridyl, N,N,N′,N′,N″-pentamethyldiethylenetriamine (PMDETA) and N-(n-propyl)-2-pyridylmethanimine (PPMI). Controlled polymerization was observed with PMDETA and PPMI ligands and poly(LMA)s with narrow molecular weight distribution (MWD) (M_w/M_n≤1.2) were obtained. The first-order time-conversion plot showed the presence of termination in the presence of PMDETA. A linear first-order time-conversion plot with a small induction period (∼10 min) was observed in the presence of PPMI ligand. Di-block copolymers of LMA and methylmethacrylate with controlled molecular weight and narrow MWDs were synthesized via sequential monomer addition.     

不同共聚单体与丙烯腈的共聚合及其表征

采用四种共聚单体衣康酸(IA)、丙烯酸甲酯(MA)、丙烯酰胺(AM)、甲基丙烯酸甲酯(MMA)分别与丙烯腈(AN)进行自由基溶液共聚合,讨论了不同共聚单体对聚合反应动力学及所得纺丝原液的粘度的影响,对聚合物的热性能进行了DSC分析,考察了不同共聚单体对聚丙烯腈原丝热性能的影响。结果表明:AN/IA体系随IA含量的增加其反应速率明显下降;与其它单体相比AM更可能有效地降低聚丙烯腈原丝的预氧化温度,缓和放热,而衣康酸次之。同时,IA含量过大,会导致原丝预氧化时的降解。     

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     

High temperature bulk copolymerization of methyl methacrylate and acrylonitrile. I. Reactivity ratio estimation

The copolymerization of methyl methacrylate and acrylonitrile has been studied in the bulk phase. Experiments for estimating reactivity ratios were conducted at 60, 100, 120, and 140°C. Tidwell–Mortimer and the feed composition constraint approaches were used to design the experiments. The error in variables model (EVM) method was employed to evaluate the reactivity ratios and analyze the error involved. The results show that the reactivity ratios do not vary significantly with temperature up to 140°C. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 843–851, 2006     

Effect of copolymerization with methacrylonitrile on the dielectric relaxation of polyacrylonitrile

Dielectric relaxation in the glass transition region of polyacrylonitrile (PAN), polymethacrylonitrile (PMAN), and their random copolymers containing 6–46 wt % MAN has been studied in the frequency range 10²–10⁵ Hz and temperature range 40–160°C. Changes in the dielectric constant increment, relaxation temperature, and the loss peak amplitude with changing MAN content in the copolymers were observed. Dielectric constant increment and loss peak amplitude showed maxima around 6–12 wt % MAN content while the relaxation temperature increased continuously over the entire range. The results are discussed in terms of the possible structural differences arising from the effect of the introduction of MAN units on the dipolar interactions between the nitrile groups.     

Improvement of the physical properties of poly(methyl methacrylate) by copolymerization with pentafluorophenyl methacrylate

Copolymers of methyl methacrylate (MMA) and pentafluorophenyl methacrylate (PFPMA) of various compositions were prepared with a free‐radical initiator. When PFPMA was included in the copolymers, the glass‐transition temperatures increased and showed a positive deviation from the Gordon–Taylor equation. A copolymer containing 20 wt % PFPMA exhibited almost zero orientational birefringence, and the photoelastic birefringence became zero when the copolymer contained 13 wt % PFPMA. When 20 wt % PFPMA was incorporated into the MMA copolymer, its water absorption decreased to 0.4 wt % versus 1.8 wt % for poly(methyl methacrylate) (PMMA) under the same condition. The flammability of the PFPMA/MMA copolymer was reduced in comparison with that of the MMA homopolymer. The refractive indices of the PFPMA/MMA copolymers were very close to that of PMMA, and the transmittances of the copolymers were slightly better than that of PMMA. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Solvent effects in free radical copolymerization of styrene and methacrylonitrile

The reactivity ratios for the free radical copolymerization at 60°C of methacrylonitrile (M₁) and styrene have been determined in benzene, benzonitrile, acetonitrile and benzyl alcohol solutions. In the first three systems there is a minor solvent effect on r₁ which may be attributable to changes in the dielectric constant of the solution. In benzyl alcohol there is a marked solvent effect, which has not been satisfactorily explained, on both r₁ and r₂.     

Improvement of the mechanical stability of oak by radiation-induced in-situ copolymerization of allyl glycidyl ether with acrylonitrile and methyl methacrylate

This study deals with the improvement of the mechanical stability of oak, which belongs to the hardwoods, by radiation-induced in-situ copolymerization of certain monomers. Acrylonitrile (AN), methyl methacrylate (MMA), allyl glycidyl ether/acrylonitrile (AGE/AN), and allyl glycidyl ether/methyl methacrylate (AGE/MMA) monomers and monomer mixtures were employed to conserve and consolidate the wood. After impregnating oak with these monomer mixtures, polymerization was accomplished by γ-irradiation. The relationships between the mechanical properties of the wood/(co)polymer composites and the anatomic structure of the wood, the types and the quantity of the polymer and copolymer, the irradiation dose and the aging process were explored. The fine structure of the wood/(co)polymer composites and the compatibility of wood with polymer and copolymer were investigated by scanning electron microscopy. The existence of polymer and copolymer in the wood enhanced the mechanical durability of the wood. The results of the hardness and the compressive strength tests applied in the parallel and perpendicular directions to the fibers of the wood/(co)polymer composites show that P(AGE/MMA), P(AGE/AN) copolymers are effective in raising the mechanical durability. In the case of P(AGE/MMA), the increase in the compressive strength perpendicular to the fibers in the oak wood is 179% at highest conversion. Similar results were also acquired from hardness tests. The decrease in the mechanical durability after aging for 28 d was very little.     

Graft copolymerization of poly(methyl methacrylate) with some alkyl methacrylates by atom transfer radical polymerization method and thermal properties

The preparation of graft copolymers of poly(methyl methacrylate) with some alkyl methacrylates were carried out via atom transfer radical polymerization method catalyzed by CuCl/2,2′-bipyridine and using a macroinitiator, poly[(methyl methacrylate)-co-(3,5-bis(chloroacetoxy)phenyl methacrylate)], including an amount of 1 mol % having α-halogeno carbonyl group in the side groups. Although the number-average molecular weights of a graft copolymer series of n-butyl methacrylate (n-ButMA) ended at different times increased from 55,700 to 99,500, the polydispersities decreased from 1.85 to 1.39 with time. The thermal degradation kinetics of macroinitiator and a two-armed graft copolymer of n-ButMA with this macroinitiator, PMMA-g-PnButMA: 4% (by mol), were carried out at different heating rates by thermogravimetric analysis and the results were compared. Using both the Flynn–Wall–Ozawa and Kissinger methods, the decomposition activation energies for macroinitiator were determined as 168 and 162 kJ/mol, respectively; they were also calculated as 233 and 239 kJ/mol for PMMA-g-PnButMA: 4%. The solid state thermodegradation mechanisms of both macroinitiator and PMMA-g-PnButMA: 4% are R₁-type mechanism, a phase boundary-controlled reaction, and F₁-type mechanism, a random nucleation with one nucleus on the individual particle, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Graft copolymerization of vinyl monomers with modified cotton. II. Grafting of acrylonitrile and methyl methacrylate on acetylated cotton

Ce(IV)-induced polymerization of acrylonitrile and methyl methacrylate with acetylated cotton having different acetyl contents was investigated. The extent of interaction between the cotton and monomer is dependent upon the acetyl content of the former as well as on the reaction conditions. Increasing the acetyl content caused a significant decrease in the graft yield. Increasing the acrylonitrile concentration was accompanied by a substantial increase in the graft yields. The same effect was found with the initiator up to a certain concentration, but beyond it there was a reversal. The rate of grafting increased by rising the temperature and follow the order 60° > 40° > 30°C. The Ce(IV) consumption during grafting is greater than that consumed during oxidation. The consumption of Ce(IV) by the cellulosic materials was favorably influenced by the concentrations of monomer and initiator, time, and temperature. Rates of grafting and Ce(IV) consumption during oxidation of acetylated cottons having different acetyl contents strongly support the postulated mechanism of grafting using the Ce(IV)–cellulose redox system. Ce(IV) oxidation had practically no effect on the acetyl groups (expressed as per cent combined acetic acid) of the modified cotton.     

Mechanical properties of products of thermocatalytic and radiolytic styrene–acrylonitrile copolymerization

The mechanical properties of styrene (S)–acrylonitrile (AN) mixtures, ranging from 20 to 80 wt % S, polymerized by thermocatalytic and radiolytic techniques were studied. Maximum compressive and tensile strength was obtained for the mixture containing 60 wt % styrene. The hardness increased with styrene concentration up to 40 wt % and then remained nearly constant. Radiolytic copolymerization gave stronger copolymers than thermal copolymerization since irradiation enhances crosslinking. For the same composition, as the dose increases, the strength increases to a maximum and then decreases due to competing rates of crosslinking and degradation.     

Kinetic study of copolymerization of acrylonitrile with ammonium acrylate

Ammonium acrylate was first used to successfully copolymerize with acrylonitrile. Kinetics of copolymerization of acrylonitrile with ammonium acrylate was investigated in a H₂O/dimethylsulfoxide (DMSO) mixture. The rate of copolymerization and particle size were measured. Kinetic equation of the copolymerization was obtained. Effect of copolymerization systems on monomer apparent reactivity ratios for acrylonitrile/ammonium acrylate copolymers was studied in comparison. Values of monomer apparent reactivity ratios were calculated by Kelen‐Tudos method. It has been found that monomer apparent reactivity ratios in water‐rich reaction medium [H₂O/DMSO>80/20] are approximately equivalent to those in aqueous suspension polymerization system. In DMSO‐rich reaction medium (DMSO/H₂O > 80/20), apparent reactivity ratios are similar to those in solution polymerization system. With an increase in polarity of solvent, values of apparent reaction ratios both decrease. The values of apparent reaction ratios gradually tend to 1 with increase in the copolymerization temperature. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4679–4683, 2006