高稳定性新型胺基镍催化剂及其催化烯烃可控聚合研究

A series of novel nickel complexes with amino-imine ligands and diamino ligands will be strategically synthesized and used as the catalyst precursors for olefin polymerization. Highly stable catalysts with high temperature resistant and steady catalysis of olefin polymerization are prepared through the adjustment on the steric hindrance and electronic effects of the ligands in order to regulate and control the branching-topologic structure of polyolefins in a widened range and carry out living polymerization of olefins at higher temperature. Effects of catalyst structure and reaction conditions on catalytic activity and branching structure, composition, molecular weight and molecular weight distribution of the obtained polymer are systematically studied to search for objective laws of catalytic stability, control of polymer branching topology and living polymerization. A series of novel polyolefin polymers is prepared by branching-structure block polymerization, block colymerization of various olefins and copolymerization of ethylene with polar monomers.

本项目设计合成新型胺基亚胺和二胺基配体系列的镍配合物作为烯烃聚合催化体。通过配体取代基立体位阻和电子效应的调节以获得能耐较高温度和催化聚合平稳的催化剂，以能在更宽范围里调控聚烯烃支化拓扑结构和实现较高温度下烯烃活性聚合。系统考察催化剂配体结构以及反应条件对催化活性以及聚合产物支化结构、组成、分子量及分子量分布的影响，探索这些新催化体系进行烯烃聚合的稳定性以及对聚烯烃支化拓扑结构控制和活性聚合的本质规律。进行不同支化结构嵌段、不同烯烃分段加料嵌段共聚合以及乙烯与极性单体共聚合研究，合成制备新颖结构的聚烯烃。

后过渡金属催化剂的热稳定性比较差，高温下通常会发生失活造成严重的活性衰减，限制了其产业化应用。本项目设计合成了高热稳定性胺基镍钯催化剂，包括胺基亚胺镍钯催化剂体系，以及α-二胺基镍催化剂体系，并对其结构进行了精细的表征。通过详细地研究聚合反应条件对乙烯和α-烯烃聚合的影响，筛选出了高热稳定性的催化剂体系，成功的实现了乙烯和α-烯烃高温活性均聚合。莰基的α-二亚胺镍催化剂能够在70℃催化丙烯活性聚合，50℃催化己烯活性聚合，胺基亚胺镍能够高选择性的催化己烯聚合，胺基亚胺钯能够催化乙烯活性聚合以及和MA共聚。采用活性聚合体系，制备了聚乙烯-聚降冰片烯，不同支化结构的嵌段共聚物，以及功能化的聚乙烯基共聚物，并对所合成的聚合物进行了精确的结构表征。研究工作进一步加深了对烯烃聚合催化剂设计的理论认识，提供了一条提高后过渡金属催化剂热稳定性的有效路径。同时也制备了结构精细的聚烯烃材料，为新型聚烯烃材料的开发应用提供基本数据。