摘要
研究了(NdCl_3+FeCl_3)r phen-HA_2(i-Bu)_2体系聚合丁二烯。通过固定催化剂中稀土(或铁)含量而改变铁(或稀土)含量的方法,证明了此聚合体系中存在两种不同的对丁二烯聚合有很高催化活性的活性中心,即能使丁二烯聚合成高顺式产物的Nd活性中心,和使丁二烯聚合成几乎是等二元(cis-1,4和1,2构型),聚合物的Fe活性中心。所得产物具确两个T_g和产物分级后可得到cis-1,4为92％和1,2含量为54％的级分,为以上结论也提供了旁证。两种活性中心的催化活性受铝比、聚合温度等的影响,稀土活性体对聚合条件比过渡金属活性体有较宽的适应范围。对其聚合机理进行了探讨,认为两种活性中心分别按各自的聚合机理进行聚合反应。
Polymerization of butadiene in the presence of (NdCl3 +FeCl3 ).nphen-HAl(i-Bu)2 was studied according to the relation between the, components of the mixed catalyst and the microstructure of the product. The results indicated that in the polymerization system there were two type active centers of higher activity, i.e. the rare earth active center which enabled butadiene to polymerize to form high cis-1,4 configuration product and the transition metal Fe-active center which caused the polymerization of butadiene to form equal bi-nary polybutadiene (1,4 and 1,2 configuration). The obtained polymer has two Tg of -67 and -35℃. Polybutadiene fractions with 92% cis-1,4 configuration and with 54% 1,2 configuration were obtained after fractionation. Both of the above facts gave additional evidence for the existence of two type active centers in the polymerization system. Catalytic activity of these two active centers was influenced by Al/M ratio, polymerization temperature and other conditions. Rare earth active center showed wider suitability than Fe-active center for the polymerization conditions. The butadiene polymerization mechanism with these two type active centers was discussed.
基金
国家自然科学基金
