TPC溶液加料低温溶液缩聚合成PPTA的研究

SYNTHESIS OF PPTA WITH LOW TEMPERATURE SOLUTION POLYCONDENSATION BY ADDING TPC SOLUTION INTO PPD SOLUTION

本文详细研究了采用对苯二甲酰氯(TPC)溶液加料(双溶液法)低温溶液缩聚合成聚对苯二甲酰对苯二胺(PPTA)的各种工艺条件对产物对数比浓粘度的影响。结果表明,盐的用量、吡啶的用量和单体浓度与TPC粉末加料具有相同的规律性。由于TPC溶液加料工艺的影响,单体摩尔比、TPC分步加料的使用、溶液放置时间及溶剂在TPC和对苯二胺(PPD)溶液配制时的分配比例等具有其特殊的规律性。在优选的条件下,TPC溶液加料工艺和固体粉末加料工艺一样,可以获得较高对数比浓粘度的PPTA。

The synthesis of poly-p-phenyleneterephthalamide (PPTA) by continuous low temperature solution polycondensation between melt terephthalyl chloride (TPC) and p-phenylenediamine (PPD) amide solvent solution and by interval low temperature solution polycondensation between PPD solution and TPC powder was well known. In this paper the synthesis of PPTA by low temperature solution polycondensation between TPC-N-methylpyrrolidinone (NMP) solution and PPD-NMP solution was studied. According to the experiment results the effect of monomer concentration and amount of pyridine(Py) and LiC1 used in improving the inherent viscosity of PPTA was the same as the results obtained in the synthesis of PPTA by adding TPC powder into PPD solution. Because of byreaction between TPC and NMP the optimum mol. ratio of monomers(TPC/PPD) was 1.02—1.03(mol.), while TPC/PPD(mol.) in synthesis of PPTA by adding TPC powder into PPD solution was 1.0065—1,015(mol.) and storage cycle time of TPC solution was less than 2 hours at room temperature. Under optimal conditions, i.e. monomer concentration: 0.3—0.4 mol./1, amount of LiCl: 1.4—1.8% by weight of solvent, Py/—NH_2=0.90-1.00(mol.), TPC/PPD=1.020-1.030(mol.), the inherent viscosity of PPTA obtained was little more than the inherent viscosity of PPTA obtained by adding TPC powder into PPD solution.