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本文合成了一类以2,3,5-三甲基氢醌(TMHQ)、对苯二甲酸(TPA)、2,6-萘二甲酸(2,6-NDA)为基本共聚单体并加有少量聚对苯二甲酸乙二酯(PET)的芳香共聚酯;研究了共聚酯的组成对溶解度、热性质、液晶性质、流变性质及晶体结构的影响。实验表明,共聚酯在某个温度范围内呈现向列型液晶的特征,其熔体粘度的切变依赖特性也证实了这一点。DSC 热谱和广角 X-射线衍射图分析证明,对某些组成,在共聚酯的分子链中存在着相应于 TMHQ-TPA 和 TMHQ-2,6-NDA 两种短嵌段结构。这是与非均相缩聚条件有关的。
In this paper, we synthesized a series of copolymers based on 2,3,5-trimethylhydroquinone (TMHQ), terephthalic acid (TPA) and 2,6-naphthalene dicarboxylic acid (2,6-NDA) A small amount of aromatic copolyesters of polyethylene terephthalate (PET) were prepared. The effects of copolyester composition on solubility, thermal properties, liquid crystal properties, rheological properties and crystal structure were investigated. Experiments show that the copolyesters exhibit nematic liquid crystal characteristics over a range of temperatures, as evidenced by the shear-dependent melt viscosity dependence. DSC thermogram and wide-angle X-ray diffraction pattern analysis showed that for some compositions, there are two short block structures corresponding to TMHQ-TPA and TMHQ-2,6-NDA in the molecular chain of copolyester. This is related to heterogeneous polycondensation conditions.