聚酰胺——聚对苯二甲酰对苯二胺的研究

详细地研究了对苯二甲酰-对苯二胺低温溶液缩聚时,各种反应条件对聚合体分子量的影响,获得了适合于液晶纺丝的高分子量聚合体,其η_(inh)可达5—7。结果表明,聚合体系的水份、单体克分子浓度、各种混合溶剂体系比对聚合体分子量有明显的影响。为获得高分子量聚合体,混合溶剂体系的最佳组成分别为:HMPA:DMAC=4:1(体积比)、HMPA:NMP=7:3 和 HMPA:THF=9:1。当水份含量大于100ppm时,将严重妨碍高分子量聚合体的得到。在缩聚反应初期,聚合体η_(inh)随时间迅速增长,两三分钟内出现凝聚现象,聚合转化率达100％。体系凝聚后缩聚反应仍然进行,聚合体仍有增长。

STUDIES ON THE POLYAMIDE--POLY (1,4-PHENYLENETEREPHTHALAMIDE)

The polycondensation of terephthaloyl chloride and p-phenylene diamine was systematically studied.High molecular weight PPTA with ηinh=5-7 were prepared and the main factors influencing the solution polycondensation of 1,4-pfoenylene diamine with terephthaloyl chloride were studied in detail. Experimental results showed that the moisture content of the reaction system, reactant concentration and volume ratio of mixed solvents have great influences on the inherent viscosity of poly-(1, 4-phenyleneterephthalamide) obtained. Highest ηinh was obtained at a reactant concentration of 0.3m/1 in a mixed solvent HMPA/DMAC ratio of 4/1 (by volume); at a reactant concentration of 0.35m/1, in a mixed solvent (HMPA/NMP) of 7/3 and at a reactant concentration of 0.5m/l in a mixed solvent (HMPA/THF) of 9/1. The water content of the polymerization system must be strictly controlled to less than 100ppm.In the early stage of polycondensation process the ηinh of the polymer obtained increased rapidly with time. The system gelatinized within two or three minutes while the consumption of monomers reached 100%. The reaction of polycondensation continued after gelation and the ηinh of the obtained polymer increased appreciably.