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通过酯交换反应,合成了一系列以对乙酰氧基苯甲酸(PHB),4.4,—二乙酰氧基二苯基丙烷(BPA)和对苯二甲酸(TPA)为单体的三元共聚酯。采用热台偏光显微镜(TOT)、示差扫描量热仪(DSC)和广角x射线衍射(WAXD),较详细地研究了液晶共聚酯的结构、性能及其与分子链组成的关系。DSC和TOT结果表明,共聚酯的玻璃化温度较高,介于166—188℃之间,熔化温度一组成关系的相图具有最低共熔点;共聚酯中PHB链节含量在10～50％时均呈现向列型液晶特征,随温度升高.均无各向同性转变,固态共聚酯具有冻结向列液晶结构。WAXD结果指出无规共聚是破坏结晶结构,降低熔点的有效手段。
A series of terpolymers of p-acetoxybenzoic acid (PHB), 4,4-diacetoxydiphenylpropane (BPA) and terephthalic acid (TPA) were synthesized by transesterification ester. The structure, properties and molecular chain composition of liquid crystal copolyesters were studied in detail by using TOT, DSC and WAXD. The results of DSC and TOT showed that the glass transition temperature of the copolyester was high, ranging from 166-188 ℃. The phase diagram of the composition of melting temperature had the lowest eutectic point. The content of PHB in the copolyester ranged from 10 to 50 %, All showed nematic liquid crystal characteristics, with the increase of temperature, there is no isotropic change, solid state copolyester has a nematic liquid crystal structure. WAXD results indicate that random copolymerization is an effective means to destroy the crystalline structure and lower the melting point.