顺序加料活性嵌段共聚合制备立构规整聚烯烃-b-极性乙烯基聚合物

The modification of high performance and functionality or functionalization of polyolefins has increasingly attracted great attention from academia and industry at home and abroad. In this project, the catalysts of IVB metal complexes with novel structure for olefin stereospecific living polymerizations and protected polar vinyl monomers living coordination polymerizations are designed and prepared in term of adjusting the ligand electronic, steric effects and fluidity as well as the electronegativity of central metal atoms. In order to implement the living block copolymerization of olefins with protected polar vinyl monomers via sequential monomer addition, which can control the stereoregularity of the polefins and the molecular weight of the polymers, the structure and property of these catalysts are optimized using the density functional theory calculations. Moreover, the mechanism of the living block copolymerization reaction and the important and common academic problems will be revealed. The protected strategies of polar functional group for polar vinyl monomers will be investigated. The conditions of mild protection and deprotection will be optimized. On the premise that the living coordination polymerization of vinyl double bond is not influenced and the polymerization products are easy to be separated and purified. The appropriate polar functional group protection measures are obtained, and the polar functional group is protected with certain stability. Therefore, it can not only prevent the polar functional groups inactivation reaction from catalyst activated species, but also can exist stably under the condition of polymerization before deprotection. Finally, the stereoregularity polyolefins-b-polar vinyl polymers are provided after deprotection.

聚烯烃高性能化和功或官能化改性受到国内外学术界和工业界的广泛关注。本项目通过调节配体的电子、空间位阻效应和流变性及中心金属原子的电负性，合成结构新颖的烯烃有规立构活性聚合和受保护极性乙烯基单体活性配位聚合的IVB金属配合物催化剂；并借助密度泛函理论计算，对催化剂进行结构与性能优化，实现能够控制聚烯烃的立构规整性和聚合产物分子量的烯烃与受保护极性乙烯基单体顺序加料活性嵌段共聚合，并揭示其中活性嵌段共聚合反应机理和重要共性科学问题。探索极性乙烯基单体官能团保护策略，优化温和保护和脱保护条件，在不影响乙烯基双键活性配位聚合，且聚合产物易于分离纯化前提下，获取适当极性官能团保护措施，使极性官能团被保护后具有一定稳定性，不仅能阻止极性官能团与催化剂活性中心发生失活反应，而且在脱保护之前的聚合反应条件下能稳定存在；经脱保护后制得立构规整聚烯烃-b-极性乙烯基聚合物。

聚烯烃高性能化和功或官能化改性受到国内外学术界和工业界的广泛关注。本项目通过调节配体的电子效应、空间位阻效应和流变性及中心金属原子的电负性，合成结构新颖的烯烃有规立构活性聚合和受保护极性乙烯基单体活性配位聚合的IVB金属配合物系列催化剂；在对催化剂进行结构与性能优化的基础上，实现：(1) 聚烯烃立构规整性和聚合产物分子量可控的烯烃配位聚合；(2) 乙烃与受保护极性乙烯基单体共聚合（包括单体同时加料和顺序加料两种方式），(3) 乙烃与苯乙烯、高级α-烯烃及环烯烃分子链结构可控共聚合。基于聚合物分子链结构表征，揭示乙烯与受保护极性乙烯基单体、苯乙烯、高级α-烯烃及环烯烃共聚合反应机理，解决重要共性科学问题。考察单体的电子效应和空间位阻效应对目标催化剂聚合行为的影响；探索极性乙烯基单体官能团保护策略，优化温和保护和脱保护条件，在不影响乙烯基双键配位聚合活性，且聚合产物易于分离纯化的前提下，获取适当极性官能团保护措施，使极性官能团被保护后具有一定稳定性，不仅能阻止极性官能团与催化剂活性中心发生失活反应，而且在脱保护之前的聚合反应条件下能稳定存在，经脱保护后制得含极性基团的聚烯烃。优化聚合条件，合成出系列分子链结构可控的烯烃均聚物和共聚物，如：有规立构聚苯乙烯、超高分子量聚乙烯、聚乙烯-b-聚对羟基苯乙烯、聚(乙烯-co-对羟基苯乙烯)、聚(乙烯-co-高级α-烯烃)、聚(乙烯-co-降冰片烯)等。本项目的实施和所取得的研究成果涉及高分子合成化学、高分子材料高性能和功或官能化改性、高分子结构与性能表征等相关科学领域，发展了聚烯烃可控合成方法学，同时揭示了烯烃配位聚合及共聚合一些相关的共性科学问题，对开发应用高性能和功或官能化立构规整聚烯烃有着非常重要的理论和实际意义。