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采用低温溶液缩聚法,在N-甲基吡咯烷酮(NMP)-氯化锂(LiCl)溶剂体系中加入2-(4-氨基苯基)-5-氨基苯并咪唑(DAPBI)作为第三单体,与对苯二胺(PPD)和对苯二甲酰氯(TPC)共聚得到改性对苯二甲酰对苯二胺(PPTA)共聚物。控制共聚单体投料顺序,设计合成出一系列序列结构不同的杂环段与PPTA硬段相间的嵌段聚合物。研究了序列结构和DAPBI含量对共聚物比浓对数黏度的影响,采用红外光谱、X射线衍射、热重分析仪等对共聚物结构和性能进行表征。试验结果表明:DAPBI成功引入到了PPTA分子链中,改性PPTA树脂为非晶结构,所得有规嵌段共聚物比无规共聚物拥有更好的有序性和结晶性能,共聚物能保持良好的耐热性能,溶解性能和力学性能得到了提升。
The polycondensation of 2- (4-aminophenyl) -5-aminobenzimidazole (DAPBI) as the third monomer in NMP-LiCl solvent system was carried out by the cryogenic solution polycondensation method. , With p-phenylenediamine (PPD) and terephthaloyl chloride (TPC) were copolymerized to obtain modified terephthaloyl-p-phenylenediamine (PPTA) copolymer. Control of the comonomer feeding sequence, design and synthesis of a series of sequence structure of different heterocyclic ring segments and PPTA hard segment phase block polymer. The influence of sequence structure and DAPBI content on the inherent viscosity was studied. The structure and properties of the copolymer were characterized by IR, XRD and TG. The experimental results showed that DAPBI was successfully introduced into the PPTA molecular chain, and the modified PPTA resin was amorphous. The obtained block copolymer showed better ordering and crystallinity than the random copolymer, and the copolymer could maintain good The heat resistance, solubility and mechanical properties have been improved.