不同梳形支化结构聚苯乙烯熔体的流变行为  

Rheological Behavior of Different Comb-Branched Polystyrene Melts

作　　者：蒋姗[1] 徐晓梅[1] 王美玉[1] 朱梦冰[1] 俞强[1] 

机构地区：[1]常州大学材料科学与工程学院,江苏省太阳能电池材料与技术重点实验室,江苏常州213164

出　　处：《高校化学工程学报》2015年第3期748-752,共5页Journal of Chemical Engineering of Chinese Universities

基　　金：江苏省太阳能电池材料与技术重点实验室资助项目(201305J)

摘　　要：以主链长度相当、支链数目和支链长度变化的一系列梳形支化聚苯乙烯为对象,采用旋转流变仪测定其流变参数,研究了梳形支化结构对聚合物熔体流变行为的影响。结果表明,梳形支化聚苯乙烯的零剪切黏度随支化数目或支链长度的增加而增大。在支链长度低于链缠结临界分子量Me时,随支链数目增加,梳形支化聚苯乙烯的零剪切黏度与重均分子量对数曲线的斜率为2.8-2.9。在支链数目一定时,当支链长度增加到链缠结临界分子量Me之前,梳形支化聚苯乙烯的零剪切黏度与重均分子量对数曲线的斜率为3.2左右。梳形支化聚苯乙烯呈假塑性流动行为,其非牛顿指数小于1,且随支链数目或支链长度的增加有小幅下降。由于支链减轻了链缠结程度,导致梳形支化聚苯乙烯的黏流活化能低于线形聚苯乙烯,随支链数目增加,对链缠结的抑制作用增大,黏流活化能进一步下降。A series of polystyrenes with the main chain lengths nearly the same and different branch lengths and branch numbers were prepared. The rheological parameters of polymers were measured by using a rotational rheometer, and the impact of the comb-branched structure on the rheological behavior was also investigated. The results indicate that, the zero-shear viscosity of comb-branched polystyrene increases with the increase of branch number and branch length. As the branch number increases, the slope of zero-shear viscosityaverage weight molecular weight curve is between 2.8-2.9. When the branch number keeps constant, and before the branch length increases to cause its molecular weight reaches its critical molecular weight of chain entanglement Me, the slope of zero-shear viscosity average molecular weight curve is about 3.2. Comb-branched polystyrene behaved as pseudo plastic fluid. Its non-newtonian index is below 1, and the value declines a little as the branch length and branch number increase. Since the branches lighten the extent of chain entanglement, the viscous flow activation energy of comb-branched polystyrene is lower than that of linear polystyrene. As branch number increases, the chain entanglement is inhibited, and the viscous flow activation energy further declines.

关 键 词：梳形支化聚苯乙烯 流变行为 支链数目 支链长度 

分 类 号：TQ325.2[化学工程—合成树脂塑料工业]