二氧化碳-环氧丙烷共聚物的链结构控制

针对制约二氧化碳-环氧丙烷共聚物(PPC)规模化应用的玻璃化温度低的问题,提出了改进PPC链结构的3个方法,即提高共聚物的分子量、制备交联型PPC、合成区域规整结构PPC.通过研究链结构变化对PPC热性能和机械性能的影响,证明通过共聚物链结构的设计和控制,可以大幅度增强PPC的分子间作用力,从而提高了PPC的使用温度,改善了PPC的使用性能.

CHAIN STRUCTURE REGULATION OF CARBON DIOXIDE-PROPYLENE OXIDE COPOLYMERS

This review summarizes our achievements in controlling the chain structures of carbon dioxide-propylene oxide copolymers(PPC).PPC with number average molecular weight(M_n) over 2×105 was obtained by double propagation mechanism,the resulted higher M_n copolymers showed improved thermal and mechanical performance than common copolymers with M_n lower than 1.5×105.Another way to regulate chain structures was employing crosslinking strategy.PPC bearing small moiety of pendant CC groups was synthesized by terpolymerization of allyl glycidyl ether,propylene oxide and carbon dioxide.Once subjected to UV radiation crosslinking,the dimension stability of the crosslinked copolymer was improved.The third way to regulate chian structures of PPC was controlling its region structure.Lewis base modification strategy on rare earth ternary catalyst was disclosed to enhance nucleophilic ability of active center,PPC with H-T linkages over 83% and M_n up to 1.0×105,was synthesized at room temperature using Y(CCl_3OO)_3-ZnEt_2-glycerine catalyst and 1,10-Phenanthroline cocatalyst.When H-T linkages increased from 69.7% to 83.2%,a 8℃ increase of T_g was found,indicating that increase of H-T structure in PPC did raise its T_g.