摘要
研究了以Nd(naph)_3-Al(i-Bu)_2H-CH_3SiHCl_2催化体系引发异戊二烯的本体聚合的规律和所得产物的结构。结果表明,催化剂的活性取决于Al(i-Bu)_2H和CH_3SiHCl_2两组分与Nd(naph)_3的摩尔比及陈化时间,与催化剂的相态无关;Al(i-Bu)_2H的链转移反应使得聚合产物的分子量较低;经IR测定各种不同聚合条件下得到的胶样的微观结构,发现其顺-1,4含量都在95％左右,从而可推论不同的活性中心对单体具有相同的聚合效果,都有利于生成高顺式的产物。
The bulk polymerization of isoprene and the microstructure of the polymer products were studied with Na(naph)3-Al(z-Bu)2H-CH3SiHCl2 catalyst system. It was shown that the state of the catalyst depended on the molar ratio of Cl/Nd and the ageing time. The catalyst system has high activity while the molar ratio of Cl/Nd is in the range of 1 to 4 and AlH/Nd is higher than 30, no matter what kind of the state of the catalyst is. The of the polymer obtained is lower because Al(i-Bu)2H has high ability of chain transfer. The cis-1,4 contents of the polymers determined by IR are about 95%.It is worth to notice that in this system, active centers of different structures probably have the same stercochemical selectivity in polymerization.
基金
国家自然科学基金重大项目
