NdCl_3·nTBP/MgCl_2-AlR_3催化体系合成丁二烯橡胶

探讨了以NdCl_3的磷酸三丁酯(TBP)溶液为主催化剂、烷基铝为助催化剂、MgCl_2为载体组成的Ziegler-Natta型催化体系引发丁二烯(Bd)聚合的某些规律。用AlEt_3作助催化剂,聚合物的顺1,4-结构含量仅为57％,反1,4-结构含量为42％;而以Al(i-Bu)_3作助催化剂,聚合物的顺1,4-结构含量为88％,反1,4-结构含量为11％。各种陈化体系中,以NdCl_3·nTBP/MgCl_2-Al(i-Bu)_3-Ip三元体系的催化活性最高,当Nd/Bd(摩尔比)为7×10~(-5)时,单体转化率达80％。低温聚合可获得高顺式、高分子量聚合物。

Synthesis of Polybutadiene Rubber with Supported Rare Earth Catalyst System

The polymer structure and the behaviour of butadiene polymerization initiated by a supported rare earth catalyst system of NdCl_3 dissolved in tributyl phosphate(TBP) and different alkyl-aluminum were investigated. The results indicated that, compared with other co-catalysts, Al(i-Bu)_3 was more suitable to match NdCl_3·n TBP/MgCl_2; with AlEt_3 as co-catalyst, the cis-1, 4 content of the polymer was only 57%, while in the case of Al(i-Bu)_3 the cis-1,4 content was as high as 88%. It was also found that the polymer structure was greatly influenced by co—catalyst and polymerization conditions. The tertiary system in which NdCl_3·nTBP/MgCl_2, Al(i-Bu)_3 and butadiene aged together had the highest activity with a convertion of over 80% and a Nd/Bd molar ratio of 7×10~(-5). The polymer obtained at low temperatures was a rubber with high cis-1, 4 content and high molecular weight.