不饱和结晶性聚酯的结晶行为研究

Crystallization behavior of an unsaturated crystalline polyester

采用差示扫描量热仪(DSC)测试一种不饱和结晶性聚酯的熔融温度,并使用Avrami方程和Jeziorny法、Ozawa法和Mo法分别对不饱和结晶性聚酯的等温结晶动力学和非等温结晶动力学进行研究,通过偏光显微镜对不饱和结晶性聚酯等温结晶后的结晶形貌进行了观察。结果表明:不饱和结晶性聚酯的熔点受升温速率的影响;等温结晶的温度越高,结晶速率也越大;晶体形貌为球晶;结晶性聚酯存在二次结晶,且随着相对结晶度的增大,结晶变得越来越困难。由于存在二次结晶,Ozawa法和Jeziorny法均出现偏移,而Mo法用于不饱和结晶性聚酯的非等温结晶动力学分析较为合适。

The melting temperature of an unsaturated crystalline polyester was monitored by DSC,and the isothermal and non-isothermal crystallization kinetics were studied using the Avrami equation and it’s modified form,the Ozawa method and the Mo method.Polarizing microscopy showed that after isothermal crystallization the unsaturated cryslalline polyester had a spherulite morphology.The results showed that the melting point of the unsaturated crystalline polyester was affected by the rate of increase in temperature,and the isothermal crystallization kinetics showed that higher crystallization temperatures increased the rate of crystallization.Analysis of the non-isothermal crystallization kinetics showed that the crystalline polyester underwent secondary crystallization and crystallization became more and more difficult as the relative crystallinity increased.Due to the presence of secondary crystallization,linear offsets appeared in both the Ozawa and the Jeziorny methods,and the Mo method was therefore more suitable for kinetic analysis of the non-isothermal crystallization of the unsaturated crystalline polyester.