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     

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     

Effect of LiClO4 on radical polymerization of methyl methacrylate

The effect of LiClO₄ on the polymerization of methyl methacrylate (MMA) with dimethyl 2,2′-azobisisobutyrate (MAIB) was investigated at 50°C in methyl ethyl ketone. The polymerization proceeded homogeneously even at [LiClO₄] as high as 3.00 mol/L. The polymerization rate (R_p) and the molecular weight of the resulting polymer profoundly increased with increasing [LiClO₄]. R_p at 3.00 mol/L [LiClO₄] was 12 times that in the absence of LiClO₄. The rate equation depended on the presence or absence of LiClO₄: R_p = k′[MAIB]^0.5 [MMA]^1.5 in the presence of 3.00 mol/L [LiClO₄] and R_p = k[MAIB]^0.5 [MMA]^1.0 in the absence of LiClO₄. The overall activation energies of polymerization were 38.5 kJ/mol in the presence of 3.00 mol/L [LiClO₄] and 77.4 kJ/mol in the absence of LiClO₄, respectively. The tacticities of resulting poly(MMA) were insensitive to the presence of LiClO₄. In the copolymerization of MMA and styrene, Q and e values of MMA increased with increasing [LiClO₄], leading to enhanced alternating copolymerizability. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 63: 1361–1368, 1997     

国产氯丁胶和MMA的接枝共聚研究

研究了国产CR - 2 4 4可接枝氯丁胶 (CR)和甲基丙烯酸甲酯 (MMA)的接枝共聚反应 ,并成功地进行了 0 .1m3和 1 .0m3的扩试生产。     

可接枝型氯丁橡胶与甲基丙烯酸甲酯接枝共聚工艺剖析

从反应系统残留氧的影响,搅拌强度及溶剂３个方面分析了可接枝型氯丁橡胶与甲基丙烯酸甲酯接枝共聚的工艺控制情况,提高了接枝共聚的重现性。     

羧甲基甲壳素接枝甲基丙烯酸甲酯的制备及成膜性

通过高速搅拌,未使用乳化剂,制备了羧甲基甲壳素和甲基丙烯酸甲酯的接枝共聚物,避免了产物中引入乳化剂杂质。利用红外光谱对接枝共聚物进行了表征。考察了不同接枝率的产物在12种常见溶剂中的溶解性,结果表明,不同接枝率的接枝共聚物都有良好的水溶性,可以形成无色透明的膜,扩大了其实际应用价值。     

MMA/N-对甲苯基马来酰亚胺乳液共聚的研究

通过乳液共聚得到N－对甲苯基马来酰亚胺（NPTMI），甲基丙烯酸甲酯（MMA）的二元共聚物，用扭辫分析，热重分析和维卡软化点测定仪研究了不同NPTMI含量对共聚物热性能的影响，以及共聚物的力学性能，流变性能，研究结果表明，共聚物初始分解温度（Tini)，失重50％时的温度，玻璃化转变温度（Tg)及维卡软化点（TViout)都随NPTMI的含量增加而提高，当NPTMI含量为15％时，Tg提高14．1℃，Tini提高23．2℃，TVicut提高8．9℃，工聚物熔体呈假塑性流体，同时共聚物熔体非牛顿指数随NPTMI含量的增加而增大。     

Graft copolymerization of methyl methacrylate onto cellulosic biofibers

In this article, we have used the potassium persulfate to initiate the graft copolymerization of methyl methacrylate onto cellulosic biofibers in aqueous medium. Different reaction parameters, such as reaction time, initiator molar ratio, monomer concentration, amount of solvent, and reaction temperature, were optimized to get the maximum percentage of grafting (50.93%). The graft copolymers thus formed were characterized by Fourier transform infrared, scanning electron microscopy, X‐ray diffraction, and thermogravimetric, differential thermal analysis, and derivative thermogravimetric techniques. A mechanism is proposed to explain the generation of radicals and the initiation of graft copolymerization reactions. On grafting, percentage crystallinity decreases with reduction in its stiffness and hardness. The effect of grafting percentage on the physicochemical properties of raw as well as grafted fibers has also been investigated. The graft copolymers have been found to be more moisture resistant and also showed better chemical and thermal resistance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

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     

Homogeneous graft copolymerization of chitosan with methyl methacrylate by γ‐irradiation via a phthaloylchitosan intermediate

The graft copolymerization of methyl methacrylate (MMA) onto chitosan was tried via a new protection‐graft‐deprotection procedure. Because the intermediate phthaloylchitosan was soluble in organic solvents, the graft copolymerization was carried out in a homogeneous system. Grafting was initiated by γ‐irradiation. The graft percentage extent was dependent on the irradiation dose and the concentration of MMA monomer, and copolymers with grafting above 100 % were readily prepared. The graft copolymers exhibited a high affinity not only for aqueous acid but also for some organic solvents. Differential scanning calorimetry measurements revealed the presence of a glass transition phenomenon, which could be ascribed to the poly(methyl methacrylate) side‐chains. Copyright © 2004 Society of Chemical Industry     

Free radical copolymerization of methyl methacrylate and allyl acetate Part 2 structure and properties

The structure of the product from the free radical bulk copolymerization of methyl methacrylate (MMA) and allyl acetate (AAc) was investigated. The mole fraction of AAc plays an important role in the copolymerization of these two monomers. Molecular weight (MW) and molecular weight distribution (MWD) are completely altered when the feed composition is dominantly AAc. NMR spectroscopy confirmed the incorporation of AAc into the polymer. However, no allyl–allyl linkages were observed at low conversions. T_g was found to be affected by the incorporation of AAc into the polymer. © 2001 Society of Chemical Industry     

Graft copolymerization of 4-vinylpyridine and methyl acrylate onto polyethylene film by radiochemical method

Graft copolymerization of 4-vinyl pyridine (4-VP) and methyl acrylate (MA) onto polyethylene (PE) was studied in aqueous medium in air by the mutual irradiation method. The percentage of grafting was determined as a function of the (i) total dose, (ii) monomer concentration, and (iii) amount of water. The effect of different alcohols such as methanol, ethanol, isopropyl alcohol, butanol, and pentanol on the percentage of grafting of 4-VP and MA was studied. The effects of different amines on the percentage of grafting of 4-VP were also studied. The graft copolymers were characterized by IR spectroscopy and thermal analysis and by identifying the isolated polymer from the grafted film. Grafted PE film was tested for permeability behavior and was found to be permeable to a 0.5% aqueous sodium chloride solution. A plausible mechanism is suggested to explain the grafting of 4-VP and MA onto PE film. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 599–610, 1998     

Graft copolymerization reaction of water-emulsified methyl methacrylate with preirradiated jute fiber

The graft copolymerization of methyl methacrylate with water-emulsified solution onto preirradiated jute fiber was studied. The jute samples were irradiated in the presence of air using a ⁶⁰Co source of gamma-radiation. A nonionic surfactant, commercially known as “Scintron (Triton X-114),” was used as an emulsifier. Homopolymerization was reduced by using 2-methyl-2-propene-1-sulfonic acid, sodium salt. The graft copolymerization was found to be dependent on the emulsifier concentration, radiation dose, temperature, monomer concentration, and reaction time. Maximum grafting level was achieved at temperatures in the range of 70–80°C, and the optimal reaction time for maximum grafting level was found to be between 3 and 5 h, depending on the radiation doses. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:459–468, 1997     

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     

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     

Sulphur-containing polyacrylates. III: UV-induced copolymerization of methyl methacrylate with some dimethacrylates containing ether or thioether linkage

The UV-induced copolymerization of methyl methacrylate (MM) with 2,2′-thiobisethanol dimethacrylate (TEDM) and MM with 2,2′-oxybisethanol dimethacrylate (OEDM) was investigated for a wide range of the diester content (6-80 mol%) in the initial mixture. The influence of the feed composition on the course of copolymerization was determined. It was found that there exists a minimum on the plot of maximum yield of soluble copolymer versus diester content at a diester content of 30 mol%. The total copolymer yields were lower in the case of mixtures containing TEDM comonomer. Determination of the reactivity ratios gave the following values: for MM + TEDM r_a = 0·21, r_b = 4·59 and for MM + OEDM r_a = 0·55. r_b = 4·42. A possible explanation of the results obtained is discussed.     

高氯氯化聚乙烯对CR与MMA接枝共聚合的影响

以甲苯为溶剂,在９０℃条件下,研究了１０份氯含量为５７％的高氯氯化聚乙烯（ＨＣＰＥ）对１００份粘接型氯丁橡胶与７５份甲基丙烯酸甲酯（ＭＭＡ）接枝共聚合的影响。结果表明,该体系与无ＨＣＰＥ体系相比,ＭＭＡ转化率约提高４０％,产物接枝效率约高５０％,接枝度约高９０％。产物含有较高相对分子质量的级分,相对分子质量分布较宽,并且有较好的物理机械性能和较高粘接强度。     

On the copolymerization of styrene and methyl methacrylate with some monomeric benzanthrone-derivative dyes

The copolymerization of styrene and methyl methacrylate with two monomeric fluorescent dyes, benzanthrone derivatives, have been investigated. The most suitable parameters of the process were determined. The copolymers obtained had an intensive stable to solvent color and fluorescence, due to the chemical bonding of the dye to the polymer's chain. It was established that between 85 and 95% of the dye reacted in the process. The course of the copolymerization was investigated by gel permeation chromatography, and the influence of the dyes on the molecular weight and polydispersity of the polymers was determined. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 91–97, 1997     

Influence of γ‐irradiation on poly(methyl methacrylate)

Poly(methyl methacrylate) (PMMA) was γ‐irradiated (5–20 kGy) by a ¹³⁷Cs source at room temperature in air. The changes in the molecular structure attributed to γ‐irradiation were studied by mechanical testing (flexure and hardness), size‐exclusion chromatography, differential scanning calorimetry, thermal gravimetric analysis, and both Fourier transform infrared and solution ¹³C‐NMR spectroscopy. Scanning electron microscopy was used to investigate the influence of the dose of γ rays on the fracture behavior of PMMA. The experimental results confirm that the PMMA degradation process involves chain scission. It was also observed that PMMA presents a brittle fracture mechanism and modifications in the color, becoming yellowish. The mechanical property curves show a similar pattern when the γ‐radiation dose increases. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 886–895, 2002