异戊二烯高反-1,4选择性聚合稀土催化剂的合成及其聚合物的功能化

Highly trans-1,4 regulated polyisoprene (TPI) possesses excellent dynamic mechanical properties, including excellent anti-fatigue properties, low rolling resistance, low heat buildup, good strength and low abrasion loss. It is now an important component of long-life "green" tires. TPI is also widely used in heat-stimulated shape memory materials, medicine used orthopaedic materials, and so on. Up to now, however, the catalyst systems that can initiate the trans-1,4 selective polymerization of isoprene have remained less explored. Based on our previous results, the purpose of the project is to design and synthesize new rare-earth metal complexes with amino-bisphosphinimine ligands and phosphinimino-imine ligands; the catalytic behavior of the resultant complexes under the presence of activators towards the trans-1,4 selective polymerization of isoprene will be investigated; the influences of the electronic and steric effects of ligands, the types of the central metals, initiation groups as well as the activators, and the polymerization conditions on the microstructures of the obtained polymer will be examined; the mechanism of the polymerization will be presented by means of isolating the reaction intermediate, and the relationship between the structure of the ligand-catalytic performances-properties of the polymer will be established to guide for more reasonable and efficient design of new catalysts. Moreover, trans-1,4 polyisoprene modified with furan ring will be prepared by chain end functionalization. Block and star copolymers will be obtained after the polymers or the compounds with active double bonds being treated with the modified trans-1,4 polyisoprene via Diels-Alder reaction.The morphology and mechanical property of the copolymers will be investigated to provide new materials for high performance tyre-tread rubber.

高反-1,4 聚异戊二烯具有滚动阻力小，动态生热低以及耐磨性好等优点，是一种新型高性能轮胎用橡胶材料，同时还可以用做形状记忆材料，医用矫形材料等。迄今能催化异戊二烯反-1,4 聚合的催化体系还十分有限。本课题拟在前期工作基础上设计与合成胺基双膦亚胺和膦亚胺-亚胺稀土配合物，研究这些配合物在助催化剂活化下对异戊二烯的反-1,4聚合的催化作用；考察配体的结构、中心金属和引发基团及助催化剂的种类、聚合反应条件对催化体系的活性和聚合产物微观结构的影响；分离聚合反应的活性种，提出相应的聚合机理，建立配体结构-催化剂活性-聚合物性能的关系，为催化剂的有效设计提供指导。同时利用链末端功能化的方法，在高反-1,4聚异戊二烯链末端引入呋喃环，并与含有活泼双键的聚合物链或化合物通过Diels-Alder反应制备嵌段结构和星形结构的共聚物。研究共聚物的微观相结构和力学性能等，为制备高性能胎面胶提供新材料。

本项目设计与合成了一系列新型稀土金属催化剂，实现了异戊二烯等单体的高选择性聚合，制备了新型的高分子材料。主要研究结果如下：（1）通过对现有催化剂进行修饰，获得了NPN型高反-1,4异戊胶稀土催化剂，并实现了异戊二烯的高反-1,4活性聚合；（2）利用该催化剂实现了来源于生物资源的单体---月桂烯的高反-1,4聚合及其与异戊二烯的反-1,4共聚合，获得了功能化的异戊胶；（3）在此基础上，我们还开展了功能化苯乙烯单体聚合行为的研究，实现了邻甲氧基苯乙烯高全同选择性聚合、邻/间/对位取代的甲氧基苯乙烯高间规选择性均聚合及与苯乙烯共聚合；（4）利用稀土催化剂实现了功能化共轭双烯烃单体的高间规、3,4-选择性聚合。