中文摘要：

二氧化碳与环氧烷烃交替共聚制备降解性聚碳酸酯是重要的绿色聚合反应之一.尽管二氧化碳共聚物的工业化已经具备了一定基础,但却受制于材料性能、品种单一等问题,发展十分缓慢.先前发展的二氧化碳基聚碳酸酯是非晶且玻璃化转变温度较低,存在高温强度迅速变差等问题.通过立构规整性聚合使碳酸酯单元在主链上有序排列可能是该类聚合物结晶的主要途径.本文重点介绍了二氧化碳与环氧烷烃的立构规整性聚合方面的最新研究进展,包括高立构规整性催化剂的设计,以及结晶性二氧化碳基聚碳酸酯的创制工作.

英文摘要：

Selective transformation of CO2 into degradable polycarbonates by the alternating copolymerization with epoxides represents an important green polymerization process. Although the commercialization of CO2 copolymers （CO2-based polycarbonates） has already made a certain progress in recent years, the further development of this green technology is suffering from material performance as well as product type etc. The main problem is that all the previously reported CO2 copolymers are amorphous and have low glass transition temperatures, which make the strength sharply decrease at high temperatures. This paper focuses on the recent progress of the stereospecific copolymerization of CO2 and epoxides, including design of highly stereoregular catalysts based on mononuclear and dinuclear cobalt（ Ill ） complexes, and discovery of various crystalline CO2- based polycarbonates. Although various highly isotactic CO2 copolymers from terminal epoxides were prepared, only two of them were found to be crystallized. On the contrary, most highly isotactic CO2 copolymers from meso-epoxides are typical semi-crystalline materials, possessing the melting points of 179 -257℃, dependent on the employed meso-epoxides. Notably,various crystalline stereocomplexes were found to be formed in the blend of equivalent crystalline or amorphous isotactic （R）- and （S）-polycarbonates. They show the enhanced thermal stability and new crystalline behavior,significantly distinct from the component enantiomer. Moreover, the cocrystallization of amorphous isotactic polycarbonates with different chemical structures and opposite configurations provided novel crystalline hetero-stereocomplexed polymeric materials. Furthermore, racemic bimetallic cobalt catalyst system mediated stereoselective copolymerization of CO2 and meso-epoxides afforded novel intramolecular stereocomplexed polycarbonates, due to highly enantioselective chain growth in an enantiopure catalyst molecule and the copolymer-chain transfer between different configuration ca