简单剪切对聚合物溶液PS/DINP相分离行为的影响  

Effect of simple shear flow on the phase separation of PS/DINP solutions

作　　者：程小莲[1,2] 杨其[1,2] 罗勇[1,2] 江耀贵[1,2] 肖淼[1,2] 蔡盛梅[1,2] 

机构地区：[1]四川大学高分子科学与工程学院 [2]四川大学高分子材料与工程国家重点实验室,四川成都610065

出　　处：《化学研究与应用》2010年第6期721-726,共6页Chemical Research and Application

基　　金：国家重点实验室专项经费资助

摘　　要：通过剪切-光学显微装置在线研究了聚合物溶液聚苯乙烯(PS)/邻苯二甲酸二异壬酯(DINP)体系在静态和简单剪切场下的浊点变化及其相结构的实时演变过程,结果发现在单向剪切场下,当PS/DINP体系中PS含量在15%以下时该体系的剪切浊点基本不随剪切速率的变化而变化;当PS含量在15%以上时该体系的剪切浊点随剪切速率的增大而先增大后减小,并且不同配比下都出现一个最高相界移动,该最高相界移动随着PS含量的增加移向更高的剪切速率。此外,还发现PS/DINP近临界组成的静态相分离过程是典型的粘弹相分离。低剪切速率下的相分离过程与静态下有些相似,初期形成网络结构,并且该结构沿流动方向变形取向,但是网络结构直至实验结束也没有发生破裂,可见低剪切速率对网络结构具有一定的稳定作用。The phase-separation structure evolution and the cloud points change of polystyrene（PS）/ diisononyl phthalate（DINP）solutions were investigated in quiescent state and under simple shear flow with an online optics-shear system.It turned out to be that when the contents of PS were below 15%（including 15%）,the cloud points change almost kept constant and the shear cloud points were equal to the cloud points without shearing;whereas the contents of PS were above 15%,the cloud points change initially increased with shear rates and then decreased,moreover,the shear cloud points were higher than the cloud points without shearing.Besides,there was a highest phase boundary shift for each composition,and the highest phase boundary shift moved to higher shear rates while increasing PS content.Besides,it was found that the phase-separation process of near-critical PS/DINP system was typically viscoelastic phase separation.The phase separation of PS/DINP with low shear rates under simple shear flow was similar to the phase separation in quiescent state,in the early stage it also lead to the formation of an ＇interaction network＇,but the network structure deformed and oriented in the flow direction.The network didn＇t break up even if the observation time was enough long.So we could conclude that low shear rates played an important role in network stabilization.

关 键 词：PS/DINP溶液 简单剪切 切致相分离 粘弹相分离 

分 类 号：O631.21[理学—高分子化学] TQ050.425[理学—化学]