分子链大尺度高度取向小尺度接近无规取向态的无规聚苯乙烯

THE STATE OF HIGH GLOBAL CHAIN ORIENTATION BUT NEARLY RANDOM SEGMENTAL ORIENTATION OF ATACTIC POLYSTYRENE

在Ｔｇ以上３０℃对无规聚苯乙烯（ａＰＳ）薄膜进行了热拉伸，然后用各种实验方法测定的结果表明，该试样在红外二向色性，光学双折射及广角Ｘ光衍射（ＷＡＸＤ）方面表现出各向同性；但是在热膨胀、溶剂溶胀以及应力应变行为方面表现出显著的各向异性．以上结果表明，该试样小区域基本上无取向，而各向异性的性质是和试样中存在的大区域取向相联系的．

The atactic polystyrene (a PS) was slowly uni axial stretched at temperature 30℃ above its Tg.The resulting samples were characterized by a series of measurements.The results of IR dichroism,WAXD and optical birefringence all showed that in the segmental sense the samples were nearly isotropic,while the global orientation was remained,this can be indicated by the large elastic recovery of samples heated to temperatures above Tg.These samples showed large anisotropy in the solution swelling,the thermal expansion and stress strain behavior.