基于单茂稀土催化丙烯/共轭烯烃“可控”共聚合设计合成新型功能性聚烯烃的研究

The copolymerization of α-olefins with conjugate alkenes for preparing the performance outstanding polyolefin has always been both a hot and difficult issue in the research of coordination polymerization. So far, the catalysts suitable for the copolymerization of propylene with conjugate alkenes are rather limited, which prevents the development of ethylene-propylene-diene terpolymer rubber and functional polyolefin. By taking the advantage of higher-coordinating ability and valence stability of rare earth metals, the copolymerization of propylene with conjugate alkenes catalyzed by the half-sandwich rare earth metal complexes would be examined. The relationship between catalyst structures and catalytic properties in the copolymerization of propylene with conjugate alkenes would be systematically analyzed. The coordinated modes of rare earth metal complexes would be investigated in details by means of isolation of intermediates and terminal groups of polymers aided with the theoretical calculation method. The effects of the structure of catalysts and substituent groups of conjugate alkenes on polymerization process would be illuminated. Through these research and analysis, break through shortcoming of the low polymerization activity and serious chain transfer in the polymerization of propylene by using rare earth catalysts, solve the scientific problem of the copolymerization of propylene with conjugate alkenes, and to achieve the controlled co(ter)polymerization of propylene, ethylene, and conjugated alkenes (such as styrene and derivatives, butadiene, isoprene, myrcene). Eventually, synthesis of new organo rare earth metal complexes which have high chemistry activity and selectivity and are superior to the existing ones, to achieve a series of high performance functional polyolefin co(ter)polymers with a great application prospects. The results of this project will provide some theoretical and practical bases for the production of the high-performance polyolefin.

α-烯烃与共轭烯烃共聚合制备性能优异的聚烯烃一直是配位聚合研究领域的热点和难点。迄今，催化丙烯与共轭烯烃共聚合的催化体系稀少，致使以共轭烯烃为组分的三元乙丙橡胶和功能化聚烯烃未能发展。本项目利用稀土金属配位数高、价态稳定的特点，提出将单茂稀土催化剂用于丙烯与共轭烯烃共聚合的研究课题，通过中间体和端基分析并辅以理论计算，探索单茂稀土催化丙烯与共轭烯烃聚合时的配位方式，揭示单茂稀土催化剂结构和共轭烯烃取代基团对共聚合过程的影响；突破稀土催化丙烯聚合活性低及链转移严重的难点，解决丙烯与共轭烯烃高效共聚合的问题，进而实现丙烯、乙烯、共轭烯烃（苯乙烯及衍生物、丁二烯、异戊二烯、月桂烯）两元及三元高效共聚合，制备组成、立体构型及序列结构可控的共聚物；发展一类在α-烯烃与共轭烯烃共聚合中展现良好性能的稀土催化剂，实现其在一系列性能优异的功能性聚烯烃合成中的应用，为高性能聚烯烃的研究提供理论和实践依据。

α-烯烃与共轭烯烃共聚合制备性能优异的聚烯烃一直是配位聚合研究领域的热点和难点。迄今，催化丙烯与共轭烯烃共聚合的催化体系稀少，致使以共轭烯烃为组分的三元乙丙橡胶和功能化聚烯烃未能发展。本项目利用稀土金属配位数高、价态稳定的特点，将单茂稀土催化剂用于α-烯烃与共轭烯烃共聚合，通过对单茂稀土催化剂结构与催化性能的研究，突破了稀土催化丙烯聚合活性低及链转移严重的难点，实现了乙烯、丙烯的高效“准活性”聚合，尤其是获得了分子量达800万以上的超高分子量聚乙烯、超高分子量聚丙烯和超高分子量乙烯-丙烯无规及嵌段共聚物；在α-烯烃高效聚合的基础上，通过催化剂结构进一步优化，解决了丙烯与共轭烯烃高效共聚合的问题，实现了丙烯、乙烯、共轭烯烃（苯乙烯及衍生物、异戊二烯、月桂烯）两元及三元高效共聚合，制备组成、立体构型及序列结构可控的共聚物，该方法不仅用廉价的共轭烯烃取代昂贵的乙叉降冰片烯，而且所获共聚物中的双键还可以进一步高效、绿色、可控转化，获得各种功能化聚烯烃和功能化三元乙丙橡胶；开发了功能基团容忍性强的高效单茂稀土催化剂，实现了苯乙烯衍生物均聚合及与乙烯、异戊二烯的共聚合，获得了高间规的功能化聚苯乙烯、功能化聚乙烯以及功能化聚异戊二烯、功能化结晶性苯乙烯热塑性弹性体，通过苯乙烯衍生物实现了聚烯烃的可控功能化；本项目发展一类在α-烯烃与共轭烯烃共聚合中展现良好性能的单茂稀土催化剂，实现其在一系列性能优异的功能化聚烯烃合成中的应用，为高性能聚烯烃的研究提供理论和实践依据。