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本文通过在NMP-CaCl_2(6％)溶液体系中,低温溶液无规共缩聚反应,研究了间位取代苯基和含氯芳基引入量对PPTA分子量、液晶性、溶解性和热性能的影响。实验结果表明,随着PPTA分子链中间位取代苯基和含氯芳基引入量的增大,所获得的共聚物分子量、液晶性、耐热性均明显下降,但溶解性增加,热分解温度仍然大于400℃,当间位取代苯基引入量大于30％时,共聚物没有液晶性.含氯芳基引入量为5％-15％时,共聚物耐燃性最好。
In this paper, the effects of the amount of meta-substituted phenyl and chlorinated aryl groups on the molecular weight, liquid crystallinity, solubility and thermal properties of PPTA were investigated by means of random copolycondensation at low temperature in NMP-CaCl_2 (6%) solution system . The experimental results show that the molecular weight, liquid crystallinity and heat resistance of the obtained copolymer decrease obviously with the increase of the amount of substituted phenyl and chlorinated aromatic groups in the PPTA molecular chain. However, the solubility, the thermal decomposition temperature Is still higher than 400 ℃, the copolymer has no liquid crystallinity when the meta-substituted phenyl group is more than 30%, and the flame retardancy is best when the content of chlorinated aryl groups is 5% -15%.