新型负载型Ziegler-Natta催化剂用于乙烯聚合

采用原位生成载体和活性中心的方法,以Mg(C2H5)2与SiCl4反应生成载体、Ti(OBu)4与SiCl4反应生成金属活性中心制备了一种新型高性能负载型Ziegler-Natta乙烯聚合催化剂(CatⅠ)。利用ICP、SEM、粒度分析仪和GPC等方法研究了CatⅠ的组成、形态、粒径分布及采用CatⅠ制得的聚乙烯的形态与性能,并与商业催化剂进行了对比。表征结果显示,CatⅠ的载Ti量较高、粒径分布均匀且催化剂颗粒呈规整的球形;采用CatⅠ制得的聚乙烯堆密度大、细粉含量低、相对分子质量分布较宽、颗粒呈规整的类球形且分布均匀。在相同聚合条件下,CatⅠ的氢调敏感性能优于商业催化剂,因此有利于对聚乙烯产品的性能进行调控。

Novel Supported Ziegler-Natta Catalyst for Ethylene Polymerization

A novel supported Ziegler-Natta catalyst(CatⅠ) for ethylene polymerization was prepared by the in situ reactions of Mg(C2H5)2 with SiCl4 and Ti(OBu)4 with SiCl4,which were used in the preparation of the support and transition metal active centers,respectively.The composition,particle morphology and particle size distribution of CatⅠ and the morphology and properties of the synthesized PE were investigated by means of ICP,SEM,particle size analyzer and GPC,and compared with those of a commercial catalyst(CatⅡ).The results showed that the Ti content in CatⅠwas higher,its particle size distribution was uniform and its particles were spherical.The PE obtained by CatⅠhad higher bulk density,lower fines content and wider molecular weight distribution.And the PE particles were spherical-like and their size distribution was uniform.CatⅠwas more sensitive to hydrogen than CatⅡ under the same conditions,so it would be favorable for controlling the properties of polyethylene.