支化程度和支链长度对支化聚苯乙烯粘弹行为的影响  

Effect of Branching Level and Branch Lengths on the Viscoelasticity of Branching Polystyrene

作　　者：徐晓梅[1] 丁雯卉 刘晶如[1] 俞强[1] 

机构地区：[1]常州大学材料科学与工程学院,江苏常州213164

出　　处：《高分子材料科学与工程》2015年第9期87-91,共5页Polymer Materials Science & Engineering

基　　金：江苏高校优势学科建设工程资助项目

摘　　要：将星形支化聚苯乙烯与线型聚苯乙烯共混组成支化体系,使用旋转流变仪测定样品的动态粘弹温度谱和频率谱,研究了支化结构对支化聚苯乙烯粘弹性能的影响。结果表明,支化程度对支化PS粘弹行为的影响与支链长度有关。长支链体系(支链的珨Mw,branch大于2 Me)中支链对链缠结具有促进作用,随支化程度增加,受相对分子质量和缠结的共同影响,支化PS在玻璃态与橡胶态的储能模量(G′)升高,玻璃化转变温度(Tg)、粘流转变温度(Tf)和主链特征松弛时间(τe)明显上升和延长,末端弹性效应增强,并在高频下观察到支链解缠结松弛。短支链体系(支链的珨Mw,branch小于2 Me)的支链对链缠结有抑制作用,随支化程度增加,支化PS的Tg,Tf和τe升速较慢,末端弹性效应表现不明显,高频下未观察到支链松弛。Branching polystyrene samples with different branching levels and chain lengths of branch were built up by mixing linear polystyrene with its counterpart of three-arms star polystyrene. The temperature spectra and frequency spectra for the samples were measured by a Rheometric dynamic analyzer to investigate the effects of branching structure on viscoelacstic behavior of branching PS. It is found that the influences of branching level on viscoelacstic behavior of branching PS depend on the length of branches. For samples with long chain branching, the modulus G＇ both in glassy and rubbery regions, Tg, Tf and τe greatly increase with branching level due to the increased molecular weight and enhanced entanglement. The terminal relaxation for the backbone becomes stronger and a relaxation corresponding to the branch disentanglements occurs at high frequencies. For the samples with short chain branching, G＇ both in glassy and rubbery region, Tg, Tf and τe also increase, but much slowly, with branching level, which can be attributed to the suppressed chain entanglement by short chain branching. The terminal relaxation for short chain branching system is much weak, and branch disentanglement relaxation is not observed in high frequency region.

关 键 词：支化聚苯乙烯 粘弹行为 支化程度 支链长度 

分 类 号：TQ325.2[化学工程—合成树脂塑料工业]