高分子液晶态有序性对其结晶过程的影响

采用退偏振光强度法、ＳＡＬＳ和ＰＯＭ测定了高分子液晶态有序微区结构随体系温度变化的规律，并用ＤＳＣ法研究具有不同有序微区结构尺寸的液晶态的结晶过程．结果发现，高分子液晶态有序性或有序微区结构是随着体系退火温度和时间的变化而变化．同时从相应的不同有序性为起始态进行结晶时，其结晶速率明显不同．并讨论了高分子液晶态的结晶机理

EFFECT OF LIQUID CRYSTALLINE ORDERING ON THE CRYSTALLIZATION RATE OF A THERMOTROPIC AROMATIC POLYESTER

The liquid crystalline (LC) ordering of nematic mesophase was investigated by measuring the transmitted depolarization light intensity of samples varied with the temperature.The depolarization intensity of a light beam passing through the sample between crossed polarisers increased with temperature during heating,and then it was decreased when the temperature clossed to Ti. The increasing of the depolarization intensity means the growth of LC ordering or domains.This result indicates that the LC ordering is different within temperature range of nematic mesophase.So that the crystallization behavior of samples crystallized from the mesophase melt of different temperatures will be different.The isothermal crystallization from mesophase melt of different LC ordering was determined by DSC.The samples were first melted at different temperature corresponding to different LC ordering for 30 min,and then crystallization was carried out at same temperature to compare their rates.The results obtained indicate that the crystallization rates from mesophase melt of different temperature were quite different for this thermotrpic aromatic polyester.It can be seen from compareison of the data between the depolization light intensity and the crystallization rate that the crystallization rate increases with increasing LC ordering or domain size at first, and then as the LC ordering was decreased the crystallization rate becomes slower when the temperature of mesophase melt close to Ti.These observations could be interpreted that high LC ordering,or large domain size,made it easy to crystallize.\=