Polymerization of 2-(4-halophenyl)-1,3-butadiene(2-XPB) and their copolymerization with isoprene using a yttrium catalyst have been examined. The β-diketiminato yttrium bis(alkyl) complex(1) activated by [Ph_3 C][B(C...Polymerization of 2-(4-halophenyl)-1,3-butadiene(2-XPB) and their copolymerization with isoprene using a yttrium catalyst have been examined. The β-diketiminato yttrium bis(alkyl) complex(1) activated by [Ph_3 C][B(C_(6) F_(5))_(4)] and Ali Bu3 shows high cis-1,4-selectivity(>98%) for the polymerization of 2-XPB(2-XPB = 2-FPB, 2-Cl PB and 2-Br PB) to afford halogenated plastic poly(dienes) with glass transition temperatures of30–55 ℃. Moreover, the copolymerization of 2-XPB with isoprene(IP) has also been achieved by this catalyst, and the insertion ratios of 2-XPB can be facilely tuned in a full range of 0%–100% simply by changing the 2-XPB-to-IP ratio. Quantitative hydrogenation of cis-1,4-poly(2-XPB) results in perfect alternating ethylene-halostyrene copolymers, and an alternating copolymer of 4-vinylbenzoic acid with ethylene is obtained by a consecutive reaction of ethylene-4-bromostyrene copolymer with ^(n)Bu Li, CO_(2) and HCl.展开更多
Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene)...Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Calculated f(e)/f values are in good agreement with those obtained experimentally. Results show that behavior of f(e)/f is mainly contributed by chemical structure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution is strain dependent.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 21634007 and 51773193)the Department of Science and Technology of Jilin Province(No. 20180101171JC)。
文摘Polymerization of 2-(4-halophenyl)-1,3-butadiene(2-XPB) and their copolymerization with isoprene using a yttrium catalyst have been examined. The β-diketiminato yttrium bis(alkyl) complex(1) activated by [Ph_3 C][B(C_(6) F_(5))_(4)] and Ali Bu3 shows high cis-1,4-selectivity(>98%) for the polymerization of 2-XPB(2-XPB = 2-FPB, 2-Cl PB and 2-Br PB) to afford halogenated plastic poly(dienes) with glass transition temperatures of30–55 ℃. Moreover, the copolymerization of 2-XPB with isoprene(IP) has also been achieved by this catalyst, and the insertion ratios of 2-XPB can be facilely tuned in a full range of 0%–100% simply by changing the 2-XPB-to-IP ratio. Quantitative hydrogenation of cis-1,4-poly(2-XPB) results in perfect alternating ethylene-halostyrene copolymers, and an alternating copolymer of 4-vinylbenzoic acid with ethylene is obtained by a consecutive reaction of ethylene-4-bromostyrene copolymer with ^(n)Bu Li, CO_(2) and HCl.
基金This project has been supported by the National Natural Science Foundation of China, 863 High Technology Project, Special Funds for Major State Basic Research Project (G1999064800).
文摘Conformational elasticity theory recently developed has been used to explore the internal energy contribution to the elastic force f(e)/f as a function of strain for poly(cis-1,4-isoprene) and poly(trans-1,4-isoprene). Calculated f(e)/f values are in good agreement with those obtained experimentally. Results show that behavior of f(e)/f is mainly contributed by chemical structure, or intramolecular interaction, supporting the experimental observations, and that the internal energy contribution is strain dependent.