二茂二氯化钛或锆与二茂基氯化钐复合催化乙烯聚合

Cp_2TiCl_2 or Cp_2ZrCl_2 Combined with (Me or t-BuCp)_2SmCl for Ethylene Polymerization

分别以二茂二氯化钛(Cp2TiCl2)和二茂二氯化锫(Cp2ZrCl2)与钐茂金属催化剂复合组成催化体系, 并以甲基铝氧烷为助催化剂,进行宽分子量分布聚乙烯合成研究.研究发现与使用Cp2TiCl2和二(甲基茂基)氯化钐复合体系相比,使用其与二(特丁基茂基)氯化钐[(t-BuCp)2SmCl]复合体系能得到具有较高粘均分子量的聚乙烯.同样,使用Cp2ZrCl2与(t-BuCp)2SmCl复合体系也能得到具有较高粘均分子量的聚乙烯。且使用含(t-BuCp)2SmCl复合体系得到分子量分布指效达3.5以上的聚乙烯。

The preparation of polyethylene with a broad distribution of molecular weight was studied using Cp2TiCl2 or Cp2ZrCl2 incorporated with (Me or t-BuCp)2SmCl and methylaluminoxane (MAO) employed as co-catalyst. The influence of parameters on the polymerization, such as molar ratio of MAO/catalyst, catalyst concentration, temperature and time have been studied in detail. It was found that the polyethylene had higher molecular weight by using Cp2TiCl2 or Cp2ZrCl2 catalytic system combined with (t-BuCp)2SmClas compared with the system combined with (MeCp)2SmCl. Meanwhile, the polyethylene obtained from (t-BuCp)2SmCl-contained catalytic system had high polydispersity (PDI>3.5).