高于玻璃化温度T_g退火对无规聚甲基丙烯酸甲酯液-液转变的影响

作     者：顾群 沈德言 GU Qun;SHEN De-Yan

作者机构：中国科学院化学研究所分子科学中心高分子物理实验室北京100080 

出 版 物：《高等学校化学学报》 (Chemical Journal of Chinese Universities)

年 卷 期：2001年第22卷第3期

页      面：508-510页

核心收录：

学科分类：081704[工学-应用化学] 07[理学] 08[工学] 0817[工学-化学工程与技术] 070305[理学-高分子化学与物理] 080501[工学-材料物理与化学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0703[理学-化学] 

基　　金：科技部攀登计划! A"高分子凝聚态物理基本物理研究"(批准号 :95 -预 -12 ) 

主　　题：液-液转变 无规聚甲基丙烯酸甲酯 退火 热处理 结构 

摘      要：Effects of annealing temperature( T a) and annealing time( t a) on the liquid liquid transition and transition intensity of atactic poly(methyl methacrylate) were studied by means of differential scanning calorimetry. With the increase of T a from 393 to 443 K, T ll shifted to higher temperature with the decrease in transition intensity, on the contrary, when T a was over 443 K, T ll declined and transition intensity increased. When T a kept constant with the increase of t a, T ll and transition intensity varied as the results described above. Moreover, the variation extent of T ll and transition intensity increased with the increase of T a, in other words, the time needed reaching the maximum extent of variation of the two parameters was decreased with the increase of T a. The dependence of T ll and transition intensity on annealing conditions may be explained by the formation of local ordered structure, i.e . stereocomplex, during the annealing process by means of Van der Waals forces between isotacitic and syndiotactic segments of the same or different chains of atactic poly(methyl methacrylate).