Abstract:

Copolymerization by coordination catalysis is one of the main approaches to prepare cyclic-olefin copolymers. For most commercialized cyclic-olefin copolymers, norbornene and tetracyclododecene are usually employed as comonomers. The content of these comonomers is the most critical factor affecting the performance of cyclic-olefin copolymers, and the introduction of comonomers is mainly governed by the catalyst used. We reviewed the organometallic catalysts applied in the copolymerization of ethylene with norbornene and tetracyclododecene according to their structural difference. The catalysts were classified as sandwich metallocene catalysts, half-sandwich metallocene catalysts, metallocene-free organometallic catalysts and late-transition metal catalysts. Special attentions have been paid to the structure characteristics of different catalysts and the influence factors of the polymerization process such as temperature, pressure, and concentration, as well as their relationship with the catalytic activity and the content of comonomers. Nevertheless, the low activity of copolymerization of tetracyclododecene demands further studies of the copolymerization. Synthesis of novel ligands, development of high activity catalysts and construction of efficient copolymerization processes will be the new focuses.

Key words: cyclic-olefin copolymers, addition copolymerization, organometallic catalyst, norbornene, tetracyclododecene

摘要：

配位催化共聚是制备环烯烃共聚物的主要方法，目前商品化的环烯烃共聚物主要由乙烯与降冰片烯或者四环十二碳烯共聚得到。共聚单体及其含量是决定环烯烃共聚物性能的关键因素，而决定共聚单体含量的最核心因素是催化剂。本文从催化剂结构的角度出发，综述了乙烯和降冰片烯/四环十二碳烯共聚用有机金属催化剂，从双茂有机金属催化剂、单茂有机金属催化剂、非茂有机金属催化剂、后过渡金属催化剂等部分进行论述，同时论述了催化剂结构及关键聚合工艺（如温度、压力、单体浓度等）对催化活性及共聚单体插入量的重要影响。此外，由于乙烯与四环十二碳烯共聚活性低，未来针对该共聚反应的研究会继续进行。合成更多新结构的配体、开发更高活性的催化剂、构建更经济有效的反应体系将会是新的研究重点。

关键词: 环烯烃共聚物, 加成共聚, 有机金属催化剂, 降冰片烯, 四环十二碳烯