丁基橡胶相对分子质量分布的影响因素研究

Investigation in Influences to Molecular Weight Distribution of Butyl Rubber

以二氯金刚烷为引发剂,烷基氯化铝为共引发剂,在低温-100～-90℃条件下进行了丁基橡胶的淤浆聚合研究,探讨了共引发剂酸性及浓度,链转移剂和链终止剂等对丁基橡胶的产率、相对分子质量及其分布的影响情况.研究结果表明,共引发剂的酸性增强,不仅有利于提高产率,也有利于加宽产物的相对分子质量分布。当以二氯乙基铝(EADC)为共引发剂时,通过改变EADC的浓度,可以调整产物中高相对分子质量级分和较低相对分子质量级分含量的变化,提高EADC浓度有利于增加高相对分子质量级分的相对分子质量和含量,而降低EADC浓度有利于增加低相对分子质量级分的含量,从而可以在一定范围内调整产物的相对分子质量及其分布。在丁基橡胶聚合体系中,外加微量链转移剂或链终止剂对产物相对分子质量分布没有明显的调节作用,但即使是极微量的链终止剂,也会导致单体转化率大幅度下降,不利于反应。

Slurry copolymerization of isobutylene with isoprene was studied with dichloro-adamantaneas as initiator in conjunction with alkylaluminum chloride as coinitiator at the temperature range from-100 to-90℃.It was discussed that yield,molecular weight and the distribution of butyl rubber were influenced from the acidity and concentration of coinitiator,chain transfer agent and terminator in the copolymerization.The results showed that the coinitiator with stronger acidity not only led to the yield increased but also molecular weight distribution of the copolymer broadened.The molecular weight and the distribution of the rubber were adjusted regularly by ethylaluminum dichloride（EADC）concentration of variation.Higher concentration of EADC was benefit for the formation with higher molecular weight while the lower one contributed to the lower weight.However,the externally added chain transfer agent and terminator hardly affected to the molecular weight distribution of the product and even trace amount of terminator resulted in a drastic decrease in monomer conversion,the copolymerization inhibited.