异丁烯-对甲基苯乙烯无规共聚物的合成与表征

Synthesis and characterization of isobutylene-p-methyl styrene random copolymer

以二枯基氯/四氯化钛/2,6-二叔丁基吡啶为引发体系,在-80℃条件下采用正离子聚合法合成了异丁烯-对甲基苯乙烯无规共聚物(IB-co-p-MeSt),研究了不同单体投料比(摩尔比)下聚合反应的特征,并通过示差折光指数仪/多角激光光散射仪/紫外检测器、核磁共振氢谱、差示扫描量热法和热重分析对无规共聚物进行了表征。结果表明,单体转化率与IB-co-p-MeSt无规共聚物的数均分子量呈线性递增关系,同时分子量分布变窄,具有活性正离子聚合特征;在聚合时间为60 min的条件下,共聚物中p-MeSt结构单元含量随着单体p-MeSt进料量的增加而增大,不同单体投料比制得的共聚物均具有1个玻璃化转变温度,且随着p-MeSt结构单元含量的增加而提高;共聚物比丁基橡胶具有更优的热稳定性。

The isobutylene-p-methyl styrene random copolymer（IB-co-p-MeSt） was synthesized by living cationic polymerization using dicumyl chloride/titanium tetrachloride/2,6-di-t-butylpyridine as initiating system at-80℃, the polymerization rules with different monomer ratios（mole ratio） were studied,and the random copolymer was characterized by differential refractive index meter/multiangle laser lingt scattering meter/ultraviolet detector,1H-nuclear magnetic resonance and differential scanning calorimetry and thermogravimetry.The results showed that the number-average molecular weight increased in a linear way with increasing monomer conversion,the molecular weight distribution became narrow,and the copolymerization behaved as living carbocationic polymerization.Under the condition of polymerization time of 60 min,the content of p-MeSt unit increased with increasing the monomer p-MeSt,and the copolymers with different monomer ratios all had one glass transition temperature,which increased with increasing the content of p-MeSt unit.The thermal stability of the copolymer was better than that of butyl rubber.