聚对苯二甲酰对苯二胺低温溶液的缩聚反应动力学

Kinetics of Solution Polycondensation of Poly(p-phenyleneterephthalamide)at Low-Temperature

采用N-乙基吡咯烷酮-氯化钙(NEP-CaCl2)溶剂体系对聚对苯二甲酰对苯二胺(PPTA)聚合工艺进行探索,制备出高相对分子质量的PPTA聚合体.在N-甲基吡咯烷酮-氯化钙(NMP-CaCl2)溶剂体系中加入聚乙烯吡咯烷酮(PVP),可提高PPTA在聚合溶剂体系中的溶解性能,并相对延长了反应时间、加快反应速度、提高产物的比浓对数黏度,PPTA的相对分子质量约提高了40%.PVP水溶液和稀盐酸溶液的红外光谱测试结果表明:PVP不是酸吸收剂,溶剂体系中加入PVP不影响PPTA的化学结构.对PPTA缩聚反应动力学的研究可知,在NEP-CaCl2、NMPCaCl2和NMP-CaCl2添加PVP的3种溶剂体系中缩聚反应均为二级反应,PVP在聚合过程中并非起催化剂的作用.研究结果为PPTA缩聚反应工艺控制提供一定的理论依据.

Poly（p-phenyleneterephthalamide） （PPTA） polymer with high molecular weight is polymerized in the NEP/CaCl2 solvent system.The solubility of PPTA in the polymerizing solvent system is increased,reaction time is prolonged comparatively,reaction speed is accelerated,inherent viscosity of polymer is advanced,and molecular weight of PPTA polymer is improved by 40％ with the addition of PVP in NMP/ CaCl2 solvent system.The infrared spectra of PVP in water and dilute hydrochloric acid show that the PVP is not an acid absorbent,and the addition of PVP does not affect the chemical structure of PPTA.The polycondensation reactions are all the second order reactions in NEP/CaCl2,NMP/ CaCl2 and NMP/ CaCl2 with PVP solvent systems,PVP does not act as a catalyst in polycondensation.The research results provide a theoretical basis for the control of PPTA polycondensation process.