非缠结苯乙烯-对叔丁基苯乙烯共聚物的非线性拉伸流变行为  

Nonlinear Elongational Rheology of Unentangled Poly(styrene-co-p-tert butyl styrene)Copolymers

作　　者：洪宗昊 吴世龙 陈全[1,2] HONG Zong-Hao;WU Shi-Long;CHEN Quan(State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China;School of Applied Chemistry and Engineering,University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院长春应用化学研究所,高分子物理与化学国家重点实验室,长春130022 [2]中国科学技术大学应用化学与工程学院,合肥230026

出　　处：《应用化学》2024年第8期1098-1106,共9页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金(No.52103021)资助。

摘　　要：聚焦于苯乙烯和对叔丁基苯乙烯的非缠结聚合物以及其共聚物样品的线性和非线性拉伸流变学性质。所有样品均具有相似的链均库恩链段数(约为30个),表现出相似且符合Rouse模型预测的线性黏弹行为。在单轴拉伸实验中,样品在快速拉伸过程,即韦森堡数大于1的过程中拉伸黏度呈现出随拉伸速率增加先“增稠”后“变稀”的行为,在样品具有相似的最大拉伸比λ_(max)=√n_(K)(≈6)前提下,二者转变的特征韦森堡数随着叔丁基苯乙烯含量的增加而增加。该结果表明,链沿拉伸方向的共同取向导致的链段摩擦系数减少效应随着侧基数量的增加而弱化,侧基具有一定的“溶剂化”作用。Linear and nonlinear rheological properties were examined for unentangled polystyrene(PS),poly(p-tert butyl styrene)(PtBS),and their copolymer samples.All samples exhibited similar linear viscoelastic behavior,which was well predicted by the Rouse model owing to their similar average number of Kuhn segments per chain(about 30).Under the fast uniaxial elongational flow(with Weissenberg number Wi>1),the sample exhibited“thickening”followed by“thinning”with increasing the elongational rate.This transition was attributable to the reduction of friction coefficient owing to the chains'coalignment along the elongational direction.Under the condition that the samples have a similar maximum stretch ratio λ_(max)=√n_(K)(≈6),the characteristic Wi for this transition increased with the content of tBS,reflecting that the tert-butyl groups may serve as the solvent to weaken the frictional reduction.

关 键 词：聚苯乙烯 聚对叔丁基苯乙烯 非线性拉伸流变学 

分 类 号：O631[理学—高分子化学]