主链全芳热致液晶共聚酯的合成与表征

Synthesis and Characterization of Thermotropic Liquid Crystalline Polyesters/Glass Fiber In-situ

以对羟基苯甲酸(HBA)、4,4-联苯二酚(HB)、1,3-二溴丙烷(DP)、对苯二甲酸(TA)为共聚物单体,采用熔融直接缩聚的方法,一步混合直接投料聚合出全芳香族液晶共聚酯。该合成方法反应条件温和,产物分子量高。用红外(FIR)、差热分析(DSC)、偏光显微镜(POM)等测试分析手段对共聚酯的结构、热性能和液晶特性进行了表征。研究结果表明,合成所得的热致液晶共聚酯呈现明显的向列性热致液晶的特性。取代基的引入降低了共聚酯的熔点,而取代基链长直接影响共聚酯的熔点。

A series of all-aromatic polyesters with high molecular weight derived from p-hydroxybenzoic,4,4-dihydroxybenzophenone,1,3-dibromobutane,terephthalic acid were synthesized by polycondensation method.The liquid crystalline behaviors and thermal properties of the all-aromatic polyesters have been characterized by polarized optical microscopy（POM）,thermogravimetric analysis and differential scanning calorimetry（DSC）.The results show that all-aromatic polyesters with high molecular weight can be synthesized in an easily controlled mild condition as compared with the usual eater exchange reaction. Under polarizing optical microscope all the synthesized polyesters with different ratios of bisphenols have a very high degree of birefringence with threaded nematic texture in the molten state and strip texture after shearing from the melt. The results of show that the rigidity of the backbone together with the presence of the short length spacer results in high Tg value.