【摘要】 本文通过熔融酯交换和Schottern-Baumann缩聚反应合成了两类组成相同而序列结构不同的基于对羟基苯甲酸、对苯二甲酸和二元酚的三元共聚酯,用热台偏光显微镜、DSC和X-射线衍射,较详细地研究了序列结构对液晶相类型、转变温度和固态结构等的影响。结果表明,无规共聚酯较规则共聚酯的熔化温度普遍降低;但序列结构的差异并不改变液晶相类型,规则共聚酯和无规共聚酯均为热致向列型液晶,两类共聚酯固态结构的差异可用结构单元的相似性进行解释。更多还原

【Abstract】 Two kinds of liquid crystalline copolymers, based on p-hydroxybenzoic acid, terephthalic acid and diphenols, with regular or irregular sequence structure were synthesized by melt transe-sterification or Schottern-Baumann polycondensation. Polarizing microscope, DSC and X-ray diffraction were applied to investigate influence of sequence structure on mesogen, phase transition and solid structure of the polymers. It was found that sequence structure of liquid crystalline copolyesters has a strong influence on phase transition. Generally melting temperature of irregular copolyesters is depressed compared with their regular isomers, While the type of mesogen remains unchanged, both are thermotropic nematic phase. The solid structure of the copolyesters can be explained on the basis of structural unit similarity.更多还原