掺杂MgCl_2负载Z-N催化剂合成宽相对分子质量分布聚乙烯  

Synthesis of polyethylene with broad molecular weight distribution by Ziegler-Natta catalysts supported on doped MgCl_2

作　　者：陈永平[1] 范志强[1] 王齐[1] 傅智盛[1] 徐君庭[1] 徐红[1] 

机构地区：[1]浙江大学高分子科学研究所,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2006年第11期1900-1904,共5页Journal of Zhejiang University：Engineering Science

基　　金：国家自然科学基金资助项目(20274037)

摘　　要：分别以MgF2和AlCl3掺杂的MgCl2醇合物为载体,制备了TiCl4负载Ziegler-Natta催化剂,采用广角X射线衍射(WAXD)表征了催化剂的结构.在MgCl2/TiCl4负载催化剂的载体中掺杂MgF2使催化剂活性明显提高,但是对聚乙烯的相对分子质量分布影响不大.在载体中掺杂AlCl3的催化剂虽然活性略有下降,但聚乙烯的相对分子质量分布显著增宽(重均与数均分子质量之比从10.4增大到27.7).以纯AlCl3为载体的TiCl4负载催化剂催化生成相对分子质量分布极宽的聚乙烯(重均与数均分子质量之比为55.2),而其催化活性为MgCl2/TiCl4负载催化剂的一半左右.Ti-based Ziegler-Natta catalysts supported on MgCl2 doped with MgF2 and AlCl3 were prepared by the reaction of MgCl2/MgF2-ethanol adduct or MgCl2/AlCl3-ethanol adduct with TiCla, and the effect of doping on the catalyst performance in ethylene polymerization was investigated. The catalyst structure was studied by wide-angle X ray diffraction （WAXD）. Doping MgF2 in the catalyst caused increase in activity, while the molecular weight distribution （MWD） of polyethylene was little affected as compared to catalyst based on 100% MgCl2 support. Catalysts based on AlCl3 doped MgCl2 support showed a slightly lower activity than the undoped catalyst, but the polydispersity of polyethylene markedly increased with increasing AlCl3 content （Mw/Mn, from 10. 4 to 27.7）. When pure AlCl3 was used as the support, polyethylene with very broad MWD （Mw/Mn = 55.2） was produced, though the activity was only half that of the MgCl2/TICl4 catalyst.

关 键 词：聚乙烯 相对分子质量分布 Z-N催化剂 掺杂MgCl2 

分 类 号：O632.12[理学—高分子化学]