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11.
Loc Quach Takayuki Otsu 《Journal of polymer science. Part A, Polymer chemistry》1981,19(10):2405-2418
Alternating head-to-head (h-h) copolymers of methyl or n-butyl acrylates with the corresponding methacrylates were synthesized by alternating copolymerization of ethylene with citraconic anhydride, followed by esterification and Characterization. The respective equimolar (1:) head-to-tail (h-t) copolymers were also prepared by conventional radical copolymerization as comparison. The alternating, relatively low molecular weight h-h copolymers obtained showed softening, glass transition, and degradation temperatures somewhat higher than those displayed by the 1:1 h-t copolymers. After pyrolysis the main decomposition products from both h-h and h-t copolymers were alcohols, acrylates, and methacrylates. Furthermore, the ratios of alcohols to acrylates were larger for the h-h than for the h-t copolymers and smaller for the methyl than for the n-butyl esters. 相似文献
12.
Tsuneyuki Sato Toshio Kadowaki Hiroshi Takeda Takayuki Otsu 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):1225-1239
(S)-4-Methyl-2-N,N-dimethylaminopentyl methacrylate (DMAPM) was synthesized from the reaction of N,N-dimethyl-L-leucinol with methacryl chloride, and its radical polymerization was investigated. It was found that DMAPM readily polymerized by α,α1-azobisisobutyronitrile (AIBN) as an initiator to give poly-DMAPM. The copolymerization of DMAPM(M1) with styrene(Mz) was also studied in various solvents with AIBN as an initiator at 60°C. From the result obtained in benzene, Q and e values of DMAPM were determined to be 0.64 and -0.04, respectively. Specific rotations of the copolymers of DMAPM with styrene were not proportional to the weight percent of the DMAPM unit incorporated, but the observed relation gave a downward curve. The copolymerizations DMAPM with α, β-disubstituted monomers such as maleic acid, maleimide, and N-phenylmaleimide were carried out in order to induce asymmetric center in the polymer chain. After hydrolysis of the copolymers obtained, the hydrolyzed polymers were found to be optically active, suggesting an induction of asymmetric center into the polymer chain. 相似文献
13.
A kinetic study of radical polymerization of vinyl mercaptobenzothiazole (VMBT) with α,α′-azobisisobutyonitrile (AIBN) at 60°C was carried out. The rate of polymerization (Rp) was found to be expressed by the rate equation: Rp = k[AIBN]0.5 [VMBT]1.0, indicating that the polymerization of this monomer proceeds via an ordinary radical mechanism. The apparent activation energy for overall polymerization was calculated to be 20.9 kcal/mole. Moreover, this monomer was copolymerized with methyl methacrylate, acrylonitrile, vinyl acetate, phenyl vinyl sulfide, maleic anhydride, and fumaronitrile at 60°C. From the results obtained, the copolymerization parameters were determined and discussed. 相似文献
14.
Abstract Polymers of bis(trimethylsilyl) fumarate, di-tert-amyl fumarate, and methyl tert-amyl fumarate were prepared by radical polymerization at 60 or 120°C. The polymers were converted into poly(dimethyl fumarate) via thermolysis or hydrolysis and subsequent methylation to determine the tacticity using 13C-NMR spectroscopy. The probabilities of meso addition (P m) were revealed to be 0.66 (60°C) for the bis(trimethylsilyl) ester, 0.60 (60°C) and 0.52 (120°C) for the di-tert-amyl ester, and 0.54 (60 and 120°C) for the methyl tert-amyl ester. From the temperature dependence of the P m values, the differences in activation enthalpies and entropies for the meso and racemo additions were evaluated. The microstructure of poly(dimethyl fumarate) derived from poly(maleic anhydride) was also examined. The opening and addition modes in propagation of the fumaric and maleic derivatives were discussed based on the results obtained in the present and previous work. 相似文献
15.
Polystyrene sulfonic acid resin (Amberlyst 15) was found to initiate the cationic polymerization of 1,3-dioxolane easily in bulk at 0 to 50° C, and polymers with a reduced viscosity of 0.1 were obtained. However, this resin showed only low initiator activity for the polymerizations of 2-methyl-1, 3-dioxolane and trioxane. 相似文献
16.
Toru Doi Akira Akimoto Akikazu Matsumoto Takayuki Otsu 《Journal of polymer science. Part A, Polymer chemistry》1996,34(3):367-373
Radical copolymerization of N-methylmaleimide (MeMI) as well as other N-alkylmaleimides (RMI) and isobutene (IB) was carried out with 2,2′-azobis(isobutyronitrile) as an initiator at 60°C. The initial rate of the copolymerization (Rp) was dependent on the monomer composition and was maximum at the 40 mol % of MeMI in the feed. A solvent effect on the Rp and the monomer reactivity ratio was observed in this copolymerization system, i.e., copolymerization in chloroform produced a higher Rp and an alternating tendency compared with those in dioxane (rMeMI = 0.14, r1B = 0 in chloroform and rMeMI = 0.47, r1B = 0 in dioxane). The alternating copolymer of RMI and IB shows a high glass transition temperature (Tg) and excellent thermal stability, e.g., the Tg and the thermal decomposition temperature (Td) were 152 and 363°C, respectively, for the alternating copolymer of MeMI and IB. Both the Tg and Td increased as the concentration of the MeMI unit in the copolymers increased. Colorless transparent sheets were obtained from press molding the alternating copolymers. They showed excellent mechanical and optical properties. © 1996 John Wiley & Sons, Inc. 相似文献
17.
Akikazu Matsumoto Yoshinori Sano Masahiro Yoshioka Takayuki Otsu 《Journal of polymer science. Part A, Polymer chemistry》1996,34(2):291-299
The radical polymerization of dialkyl fumarates (DRF) bearing various ester alkyl groups was kinetically studied. The propagation and termination rate constants were determined using electron spin resonance (ESR) spectroscopy. The introduction of the bulky ester alkyl groups such as a tert-butyl group decreased the termination rate constant as expected. However, it has also been revealed that the bulky groups promote propagation despite the steric repulsion. The propagation rate and mechanism are discussed in relation to the propagation manner, i.e., tacticity of the polymer. © 1996 John Wiley & Sons, Inc. 相似文献
18.
19.
The radical polymerization kinetics and mechanism of sterically hindered dialkyl fumarates (DRF) bearing various ester alkyl groups are described comprehensively. The overall polymerization reactivity of DRF, the initiation mechanism and the reactivity of the primary radicals in the polymerizations with azo initiators, the determination of the propagation and termination rate constants by means of electron spin resonance spectroscopy, the propagation mechanism and the microstructure of the polymers, and the chain rigidity of poly(DRF) and bimolecular termination process are discussed. 相似文献
20.