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在大品种聚烯烃材料中,高附加值聚烯烃通常由乙烯与α-烯烃共聚制备。ⅣB金属配合物能够为烯烃聚合和共聚提供许多催化剂模型;不仅如此,在烯烃聚合机理研究中还可以帮助理解反应中间体和活性物种。针对聚烯烃产业的实用催化剂体系,催化剂不仅满足高的催化活性,而且能够满足升温操作的稳定性。企业的利润需要高附加值聚烯烃,要求催化剂体系能够通过条件变化制得不同性能的聚烯烃材料,而且可以实现乙烯与α-烯烃的共聚。这些对配合物催化剂的需求,在ⅣB金属配合物催化剂中获得了良好地体现;能够在烯烃聚合中获得分子量从低到高的聚合物,也可以进行乙烯与(甚至含有官能团的)α-烯烃共聚制备功能聚烯烃。按照取代基团的分类,本文综述了近年来ⅣB金属配合物催化烯烃聚合与共聚研究的新进展,特别是重点讨论了具有良好热稳定性的配合物催化剂结构变化对于催化活性和聚合性能的影响。
Among the large varieties of polyolefin materials, high value-added polyolefins are usually prepared by copolymerizing ethylene with alpha-olefins. IVB metal complexes provide many catalyst models for the polymerization and copolymerization of olefins; moreover, it is also possible to understand the reaction intermediates and active species in the study of the mechanism of polymerization of olefins. A practical catalyst system for the polyolefin industry, the catalyst not only meets the high catalytic activity but also satisfies the stability of the warming operation. The profits of enterprises need high value-added polyolefins, and the catalyst system is required to produce polyolefin materials with different properties through the change of conditions, and the copolymerization of ethylene and α-olefin can be realized. These requirements for complex catalysts are well demonstrated in the IVB metal complex catalysts; polymers of low to high molecular weight can be obtained in the polymerization of olefins; it is also possible to carry out the reaction of ethylene with (even the functional group-containing) Copolymerization to prepare functional polyolefin. In the light of the classification of substituent group, recent progress in the research on olefin polymerization and copolymerization catalyzed by IVB metal complexes is reviewed. In particular, the effects of structural changes of the complex catalyst with good thermal stability on the catalytic activity and the polymerization performance are discussed .