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81.
Toshinobu Higashimura Toshio Masuda Seizo Okamura 《Journal of polymer science. Part A, Polymer chemistry》1969,7(4):1115-1129
Copolymerizations of 3,3-bis(chloromethyl)oxetane (BCMO) with some vinyl compounds were carried out with cationic catalysts in various solvents to determine what kind of vinyl compound is able to copolymerize with BCMO. p-Methylstyrene (pMS), 2-chloroethyl vinyl ether (CEVE), α-methylstyrene (αMS), and isobutene (IB) were used as comonomers. The rate of consumption of each monomer was measured by gas chromatrography. Plots of copolymer composition in the copolymerization of BCMO with pMS were characterized by S-shaped curves in several solvents. As poly-BCMO is insoluble and the vinyl polymers are soluble in benzene, the polymers obtained were separated into benzene-soluble and benzene-insoluble fractions, and the composition of each fraction was determined by elemental analysis. It was found that pMS, CEVE and IB formed a copolymer with BCMO, but αMS produced no copolymer with BCMO. Thus the formation of copolymer between a cyclic ether and some vinyl monomers was observed by a cationic mechanism. The cross-propagation mechanism is discussed on the basis of these results. 相似文献
82.
Toshio Masuda Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1971,9(6):1563-1573
The effects of salts were examined in cationic polymerization of vinyl compounds. Cationic polymerization of styrene was carried out at 0°C, with acetyl perchlorate, stannic chloride, stannic chloride–trichloroacetic acid and boron trifluoride etherate as catalysts. Tetra-n-butylammonium perchlorate, fluoroborate and iodide were used as salts. The presence of small amounts of the salts changed both the polymerization rate and the molecular weight of polymer considerably. The consideration of various effects led to the conclusion that the results are explicable principally on the basis of counterion exchange. To confirm this, the copolymerization of 2-chloroethyl vinyl ether with γ-methylstyrene was investigated at ?78°C. The copolymer composition curve when stannic chloride was used as catalyst was changed and coincided with that of polymer obtained with acetyl perchlorate catalysis when the perchlorate salt was added. This supports the concept of counterion exchange. 相似文献
83.
Proton conductive inorganic–organic hybrid membranes were synthesized from 3-glycidyloxypropyltrimethoxysiane (GPTMS), phenyltriethoxysilane (PhTES) and hydroxyalkylphosphonic acid. Two kinds of hydroxyalkylphosphonic acids, 1-hydroxyethane-1,1-diphosphonic acid (HEDPA) and hydroxyethanephosphonic acid (HEPA), were incorporated into the membranes as functional molecules for proton conduction. FT-IR and Raman studies revealed the presence of phosphonic acid groups in the hybrid membranes. 13C and 29Si NMR confirmed that a three-dimensional siloxane network was formed in the prepared hybrid membrane by hydrolysis and condensation reactions. DTA-TG analysis showed that these membranes were thermally stable up to 200 °C. The HEDPA-based system was found to have higher proton conductivities than the HEPA-based one. The proton conductivities of the hybrid membranes increased with the phosphonic acid content and temperature up to 130 °C. The conductivities of the HEDPA/GPTMS/PhTES membranes = 1/1.6/0.4 were 1.0 × 10−1 and 4.5 × 10−4 S cm−1 at 100% relative humidity and non-humidified conditions, respectively, at 130 °C. 相似文献
84.
85.
Toshinobu Suzuki Masahiko Okazaki Keiryo Mitsuhashi 《Journal of heterocyclic chemistry》1986,23(3):935-939
The title compound was reacted with four types of electrophiles and the respective reaction sites were investigated. The reaction with aryl isocyanates in the conventional way yielded the corresponding ureas. In the presence of triethylamine, the 3-amino group was diacylated with acyl chlorides. On the other hand, in the cases with arylsulfonyl chlorides and p-nitrobenzaldehyde under similar conditions, the methyl group at 5-position was preferentially attacked to give arylsulfonylmethyl and p-nitrostyryl derivatives, respectively. 相似文献
86.
T. Miki T. Higashimura S. Okamura 《Journal of polymer science. Part A, Polymer chemistry》1967,5(12):2989-2996
The amounts of tetraoxane produced in the polymerization of trioxane catalyzed by BF3·O(C2H5)2 were measured in various solvents. The maximum amount of tetraoxane produced depends on the nature of solvent used. This amount was independent of the initial concentration of the catalyst in ethylene dichloride and in nitrobenzene. On the other hand, in benzene, the amount of tetraoxane produced decreased slightly with increasing initial catalyst concentration. This result was explained by the reaction of tetraoxane produced with the residual catalyst as well as with the active center. The maximum amount of tetraoxane produced decreased, other conditions being similar, in the order, nitrobenzene > ethylene dichloride > benzene solvent. This order may be explained in terms of a longer lifetime of the active center in the more polar solvent, leading to the formation of tetraoxane. 相似文献
87.
Structure and reactivity in cationic polymerization of butadiene derivatives. IV. 1-alkoxybutadienes
Michihisa Otsuki Toshio Masuda Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1976,14(5):1157-1166
The reactivity of trans-1-alkoxybutadienes in cationic homopolymerization and copolymerizations and structure of the polymers produced were investigated. 1-Ethoxybutadiene is polymerized easily at ?78°C by various acidic catalysis. The reactivity of 1-ethoxybutadiene was similar to that of ethyl vinyl ether. The polymers produced possessed molecular weights of several thousands, and were composed of 70–95% 1,4 structure and 5–30% 3,4 structure. In the copolymerization of ethyl vinyl ether (M1) with 1-ethoxybutadiene at ?78°C in toluene by boron trifluoride diethyl etherate, r1 = 1.15, r2 = 2.62. From the Hammett plot of the relative reactivities of alkoxybutadienes (alkoxy: CH3O, C2H5O, i-C3H7O), the reaction constant p* was determined to be ?2.9. Results of the present study were compared with those of various butadiene derivatives. 相似文献
88.
Masahiko Minoda Mitsuo Sawamoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1993,31(11):2789-2797
New sequence-regulated macromonomers ( 3 ) with a vinyl ether terminal were prepared by the HI/ZnI2-mediated living cationic polymerization of vinyl ethers: CH3? CH(OR1)? CH2CH(OR2)? C(COOEt)2CH2CH2OCH?CH2 ( 3a : R1 = nBu, R2 = CH2CH2OCOPh; 3b : R1 = iOct, R2 = CH2CH2Cl). The synthesis consisted of three consecutive steps: (i) quantitative addition of hydrogen iodide to the first vinyl ether into an adduct [CH3? CH(OR1)? l]; (ii) propagation of a second vinyl ether from the adduct in the presence of zinc iodide; and (iii) quenching the resulting AB-type heterodimeric living intermediate with a carbanion [θC(COOEt)2CH2CH2OCH?CH2] carrying a vinyl ether group. The HI/ZnI2-initiated living cationic polymerization of 3a and 3b yielded narrowly distributed polymers $\left( {\overline {DP}} _{_n } \sim 10 \right)$ consisting of a poly(vinyl ether) backbone and sequence-regulated oligomer branches. The terminal vinyl ether function of 3 was also utilized to prepare pentamers and hexamers with controlled sequence of functional vinyl ethers by selective dimerization and chain extension reactions with HI/ZnI2. © 1993 John Wiley & Sons, Inc. 相似文献
89.
S. Kohjiya Y. Imanishi T. Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1971,9(3):747-761
Cationic polymerization of cyclopentadiene induced by titanium tetrachloride–trichloroacetic acid was investigated in a toluene solution at ?69 to ?77°C. All manipulations were handled under vacuum conditions. Time–conversion curves were determined accurately by following the exothermicity of the fast reaction in an adiabatic system. The polymerization kinetics were developed on the basis of a fast initiation reaction and a nonstationary-state concentration (diminishing concentration) of active species, and the propagation rate constant k2 was determined by substituting either an initial rate of polymerization or a final conversion for the kinetic equations. k2 for the present system was determined to be 350 l./mole-sec, which is larger than those so far reported for some vinyl monomers in cationic polymerization. The present method can be commonly applied to reactive monomers for the determination of k2. The nature of termination reaction is discussed in connection with the determination of k2. 相似文献
90.
Mitsuo Sawamoto Etsu Takeuchi Tamotsu Hashimoto Toshinobu Higashimura 《Journal of polymer science. Part A, Polymer chemistry》1987,25(10):2717-2727
Cationic polymerization of 2-vinyloxyethyl glycidyl ether (VEGE), a vinyl ether with an epoxy group, was conducted with various initiators in CH2Cl2 in the temperature range from +15 to ?78°C, and the possibility of its selective vinyl polymerization was investigated. BF3OEt2 polymerized both vinyl and epoxy groups of VEGE to yield polymers partially insoluble in organic solvents. HI/I2, iodine, and CF3SO3H gave soluble, low-molecular-weight oligomers with epoxy pendants. 1H-NMR structural analysis of the oligomeric products showed that the epoxy/vinyl ratio of the pendants decreases in the order: 100% epoxy ~ CF3SO3H > HI/I2 ~ I2 ? BF3OEt2. Although HI/I2 or iodine mainly polymerized the vinyl group, the reaction of the vinyl ether-type growing end with an epoxy group of VEGE took place during the polymerization, so that the monomer conversion leveled off at about 40%. 相似文献