乙烯原位共聚制备线性低密度聚乙烯的双功能催化剂体系研究进展

Research progress of bifunctional catalysts for the preparation of linear low density polyethylene through ethylene in-situ copolymerization

线性低密度聚乙烯(LLDPE)是全球增长最快的通用塑料.相较于传统的两步法,在一个反应器中同时加入齐聚催化剂和共聚催化剂组成双功能催化剂体系,催化乙烯原位共聚制备LLDPE,可以大大简化生产工艺和降低生产成本.综述了近年来乙烯原位共聚制备LLDPE的双功能催化剂体系的研究进展,分别从Ziegler-Natta催化剂/齐聚催化剂、茂金属催化剂/齐聚催化剂和非茂金属催化剂/齐聚催化剂三种体系展开讨论,指出了原位共聚法对双功能催化剂的匹配性和反应速率搭配具有很高要求,并对双功能催化剂体系的未来发展进行了展望.

As the fastest growing general plastic in the world,linear low density polyethylene(LLDPE)could be prepared by in-situ copolymerization of ethylene in one reactor with the cooperative action of oligomerization and copolymerization catalyst precursors,which could greatly simplify the process and reduce the cost compared with the traditional two-stage process.Here the recent progress of bifunctional catalyst systems for ethylene in-situ copolymerization for the preparation of LLDPE was reviewed.Three systems including Ziegler-Natta catalyst/oligomerization catalyst,metallocene/oligomerization catalyst and non-metallocene/oligomerization catalyst systems were discussed.It was pointed out that the in-situ copolymerization had high requirements for the matching of catalytic behaviors and reaction rates of the bi-functional systems.The future development of these systems was also prospected.