稀土-其它过渡金属混合催化剂用于共轭双烯烃的聚合——Ⅳ.(NdCl_3+FeCl_3)·nphen-HAI(i-Bu)_2体系对异戊二烯的聚合

本文报道由(NdCl_3+FeCl_3)·nphen-HAl(i-Bu)_2催化体系引发异戊二烯聚合的结果。在适当Nd/Pe比下,该体系对异戊二烯聚合的活性可超过单一钕或铁催化剂的活性,同时随催化剂中钕和铁含量的不同,所得产物的微观结构变化很大,当体系中钕含量由100％→0时,产物的顺-1,4结构含量由94.4％→22.1％,而3,4结构含量由5.6％→77.9％。Al/M(N=Nd+Fe)比、单体浓度和聚合温度不仅对聚合活性有影响,对产物的微观结构影响也较大。事实表明,该聚合体系中存在着两种过渡金属(Nd和Fe)活性中心,它们按各自的机理进行异戊二烯的聚合。

POLYMERIZATION OF CONIUGATED DIENES WITH MIXED CATALYST OF RARE EARTH AND OTHER TRANSITION METAL IV. Polymerization of Isoprene with(NdCl_3+FeCl_3)·nphen-HAI(i-Bu)_2 System

Polymerization of isoprene in the presence of (NdCl3+FeCl3) n Phen HAl-(i-Bu)2 was studied. The results indicate that the catalytic activity and the microstructure of polymer obtained changed greatly with changing Nd/Fe ratio in the mixed catalyst. When the content of Fe changes in the range of 0-100%, the corresponding cis-1,4 and 3,4 contents of the polyisoprene vary in the range of 94.4-22.1% and 5.6-77.9%, respectively. The catalytic activity and the polymer microstructure are influenced by Al/M ratio, concentration of monomer and polymerization temperature. In the polymerization system, there are two kinds of active centers having higher catalytic activity for isoprene polymerization.