由双(氯代酞酰亚胺)与双酚盐的亲核取代缩聚合成聚酰亚胺的研究

本工作是由双(氯代酞酰亚胺)与双酚盐,采用惯常的氢氧化钠溶液制备酚盐方法,通过亲核取代缩聚合成聚酰亚胺。研究了各种参数以及不同结构的单体对双(氯代酞酰亚胺)二苯醚与双酚的缩聚反应的影响。结果表明反应的难易一般决于苯氧负离子的电子密度和反应中心正电荷对电子的吸引力以及聚合物的溶解性。双酚A的苯氧负离子虽有较强的亲核性而且所得聚合物也有较好的溶解性,但很难得到高分子量的聚合物。从电子密度大的苯氧基同时也具有较强的与体系中微量水份形成氢键的能力出发考虑,通过多次排水方法使得双(4-氯代酞酰亚胺)二苯醚与双酚A缩聚所合成的聚酰亚胺的分子量有较大的提高,其比浓对数粘度达0.55dl/g(DMAC,30℃)。还进行了各种单体的共聚。对所合成的聚酰亚胺,进行了溶解性和热稳定性的初步研究。

STUDY ON THE SYNTHESIS OF POLYIMIDE VIA NUCLEOPHILIC DISPLACEMENT POLYCONDENSATION OF BISCHLOROPHTHALIMIDE WITH DIANION OF BISPHENOL

In this work polyimide was synthesized via nucleophilic displacement polycondensa-tion of dischlorophthalimide diphenyl ether with dianion of bisphenol. The dianion was generated by the conventional method with aqueous sodium hydroxide. Study was made on the influence of the change of variables as well as the structure of the monomer on the polycondensation. The results indicate that the ease of the reaction generally depends on the electron density of the phenoxide and the ability of the positive charge of the reactive site to invite the nucleophile as well as the solubility of the polymer thus obtained.It appears difficult to get a high molecular weight product from bisphenol A although the phenoxide ion of bisphenol A has the strong nucleophilicity and the polymer obtained therefrom has the good solubility. With the consideration that the phenoxide with the strong nucleophilicity would at the same time have the strong ability to form hydrogen bonding with the trace water in the system. High molecular weight polymer with η_i=0.55dl/g(DMAC, 30℃) was obtained from the polycondensation of bisphenol A and bis(4-chlorophthalimide) diphenyl ether via multi-stage removal of water from the system.The copolycondensation of several monomers was conducted.The thermal sta-bility of the homo-or copolymers have been studied preliminarily.