PET/HBA/TA/HQ四元共聚酯形态及相结构的研究

Morphology and Phase Behavior of the PET/HBA/HQ/TA Copolyesters

研制了一套蚀刻方法并对聚对苯二甲酸乙二醇酯/对羟基苯甲酸/对苯二甲酸/对苯二酚(PET/HBA/TA/HQ)体系的共聚酯液晶试样断面进行蚀刻,并用扫描电镜观察,发现此类共聚酯中存在两相结构。当PET摩尔分数小于50％时,分散相呈球状且富含PET,连续相富含全芳族链段;当PET摩尔分数等于或大于50％时,分散相和连续相结构发生颠倒,连续相富含PET,分散相球状粒子富含全芳族链段且为纤维状结构。因此可以断言,用熔融缩聚方法制备的PET/HBA/TA/HQ四元共聚酯不是无规共聚物,而是嵌段共聚物。

A series of etching methods were developed for the morphology observation of liquid crystalline copolyester. Phase behavior of the PET/HBA/HQ/TA copolyester was investigated by SEM after etching. A two-phase structure of these copolyesters was found. When PET molar fraction is lower than 50%, HBA/HQ/TA-rich-phase is a continuous phase, while the dispersion particles are PET-rich-phase. When PET molar fraction is equal to or greater than 50% , PET-rich-phase constitutes continuous phase, while HBA/HQ/TA-rich-phase forms dispersion particles which are composed of fibers. Therefore this PET/HBA/HQ/TA copolyester is not a random copolymer but a block one with long PET blocks.