大环内酯开环聚合研究与结构明确多嵌段共聚物合成

Long chain aliphatic polyesters (LCAPs) have attracted much more attentions because of their polyethylene-like physical properties and environmental friendly characteristics. This project aims at development of novel catalytic system and synthesis of LCAP from ring-opening polymerization (ROP) of macrolactone. The transesterification side reaction can be depressed and well-defined LCAP with high molecular weight can be obtained by exquisitely modulating the structure of Lewis pairs. Furthermore, we will develop a novel approach to multi-block copolymer. Well defined multi-block copolymers of macrolactone and L(D)-lactide will be synthesized efficiently from the ROP of cyclic polylactic acid and cyclic long chain polyester with low molecular weight by using Lewis pairs. Finally, polyester materials with improved heat resistance, flexibility, mechanical strength and melt strength will be obtained by forming stereocomplex in the multi-block copolymers.

由于兼具有聚乙烯的物理性能和脂肪族聚酯的环境友好特性，长链脂肪族聚酯已受到广泛关注。本项目以大环内酯的高效可控开环聚合反应为研究对象，优化Lewis Pairs催化剂结构与性能，抑制开环聚合过程中酯交换副反应，合成结构明确高分子量长链脂肪族聚酯。进一步利用不存在酯交换副反应的Lewis Pairs催化低分子量环状聚乳酸与环状长链聚酯共聚反应，合成结构明确高分子量大环内酯/L(D)-丙交酯多嵌段共聚物，发展简单、高效合成多嵌段共聚物的新方法。最后，制备结构较完善的多嵌段共聚酯立构复合物，提高材料的耐热性、柔韧性、机械强度和熔体强度，获取综合性能优异的聚酯材料。

十五内酯可控开环聚合是制备”类聚乙烯”聚酯相对简单的方法，可在温和条件下获得分子量较高的聚合物。本项目以十五内酯开环聚合反应为研究对象，根据熵驱开环反应特点，筛选、优化了可抑制酯交换副反应Lewis pairs催化体系，建立了合成结构明确高分子量”类聚乙烯”(共)聚酯新方法。通过配体结构设计与优化，获得了新型Salen-铝配合物，该配合物可高效催化十五内酯开环(共)聚合，制备”类聚乙烯”聚酯材料。