聚酰胺酸盐薄膜的亚胺化历程研究

Study on the Imidization Process of Poly(amic acid) Salt

采用3,4,3′,4′-联苯四甲酸二酐与4,4′-二氨基二苯醚为单体,聚合中间体聚酰胺酸与有机碱成盐得到聚酰胺酸盐,研究了不同三乙胺含量及有机碱类型在原位升温/等温条件下与聚酰胺酸盐亚胺化程度和历程的关系。结果表明,聚酰胺酸盐的亚胺化温度随着三乙胺含量的增加明显降低,100%三乙胺含量下体系起始和完全亚胺化温度比聚酰胺酸分别下降了80℃和70℃。聚酰胺酸盐的亚胺化历程存在与聚酰胺酸相似的“动力学中断”现象,聚酰胺酸盐在快、慢两个阶段的亚胺化速率常数也远高于聚酰胺酸。对比有机碱的结构特点初步发现,碱性更强的有机碱制备的聚酰胺酸盐具有更低的亚胺化温度。

The poly amic-acid(PAA)was obtained via the polymerization of 3,4,3′,4′-diphenyltetracarboxylic anhydride and 4,4′-diaminodiphenyl ether.Then the PAA solution was mixed with organic base to obtain poly(amic acid)salt(PAAS).The isothermal imidization process,the relationship between the imidization degree of PAAS with different triethylamine contents and temperatures,as well as the relationship between the type of organic base and imidization process were fully studied.The results show that the imidization temperature of PAAS decreases obviously with the increase of triethylamine contents.The initial and complete imidization temperature of PAA decrease by 80℃and 70℃,respectively,comparing with that of PAA with 100%triethylamine contents.PAAS shares the similar“dynamic interruption”phenomenon with PAA in imidization process.The imidization rate constants of PAAS in fast and slow stages are also both much higher than those of PAA.By comparing the structural characteristics of organic bases,it is preliminarily found that PAAS prepared by organic base with stronger alkalinity has lower imidization temperature.