增长链在活性自由基聚合和开环聚合之间来回穿梭的聚合反应研究

The development of new polymerizations and research on the mechanism of polymerizations are the basis of polymer chemistry, and can provide new polymers and new materials for polymer material science. Chain shuttling polymerization (CSP) is a new polymerization strategy developed in recent years, and the growing chain can shuttle between two or more active species. To date, most of the chain-shuttling polymerizations relate to coordinative polymerization of olefins, and the type of monomers that can be applied in CSP is very limited. Developing new CSP that it is compatible with a wide range of monomers is important for the synthesis of new polymers and the future of CSP. We propose a new chain-shuttling polymerization system in which dithioesters or trithiocarbonates can mediate controlled radical polymerization of vinyl monomers and ionic ring-opening polymerization of cyclic thiirane monomers simultaneously, and the polymerization can shuttle back and forth between them. The polymerization behavior and structure of polymer can be adjusted by RAFT agents, catalysts, light intensity and temperature, et al., and this polymerization strategy provides a powerful tool for producing multiblock copolymers of vinyl monomers and cyclic thiirane monomers that have not been accessible by other polymerizations. This project develops a new chain shuttling polymerization in which the polymerization reaction can easily shuttle back and forth between two distinct polymerizations, and broaden the range of monomers available for chain shuttling polymerization.

聚合反应新方法的建立和聚合反应机理研究是高分子合成化学的基础，为高分子材料科学研究提供新型聚合物和新材料。链穿梭聚合是近年发展起来的新聚合方法，聚合物增长链在两个或多个活性中心间不断穿梭。目前已经报道的链穿梭聚合通常仅适用于烯烃的配位聚合，而且能适用的单体种类非常少。因此，发展能适用于多种单体的新型链穿梭聚合体系对于合成种类更丰富的新型高分子以及链穿梭聚合今后的发展非常重要。本项目设计了由二硫代酯或三硫代碳酸酯调控的，链增长反应能够在烯类单体的可控自由基聚合和硫杂丙环单体的阴离子开环聚合反应之间来回穿梭的新型链穿梭聚合反应体系。通过改变RAFT试剂和催化剂种类、光强和光照时间、温度等反应条件实现对聚合反应行为和聚合物链结构的调控，得到用其它聚合方法难以得到的烯类单体和硫杂丙环的新型多嵌段聚合物。本项目发展了可在两种不同聚合方式间来回穿梭的新型链穿梭聚合，拓宽了可用于链穿梭聚合的单体范围。

链穿梭聚合可以使增长链在两个或多个活性中心之间不断穿梭，制备出新型共聚物。目前已经报道的链穿梭聚合通常仅适用于烯烃的配位聚合，而且能适用的单体种类非常少。本项目发展了由三硫代碳酸酯调控的，链增长反应能够在烯类单体的可控自由基聚合和环硫烷烃的阴离子开环聚合反应之间来回穿梭的新型链穿梭聚合反应体系，并进一步构建了光热外场刺激精准调控共聚物链结构的策略。不仅实现得到用其它聚合方法难以得到的烯类单体和环硫烷烃的新型多嵌段聚合物，还能精准调控共聚物的组成和序列结构。此外，本项目还发展了乙烯和环烯酮缩醛的可控自由基共聚体系以及以硫羰内酯开环为媒介的串联共聚合制备了可降解共聚物材料；发展了多功能罗丹宁化学制备出复杂多环共聚物。本项目的研究成果为新型共聚反应的构建和新型共聚物材料的合成提供了思路与可靠依据。