以PMDA、ODPA和BZD为单体合成了均聚和共聚PAA。采用一步法溶液热酰亚胺化工艺和两步法涂膜热酰亚胺化工艺,分别制备了均聚和一系列共聚PI粉末和薄膜。POM、X—ray研究表明,PMDA/ODPA—BZD票聚PI粉末的结晶度随着ODPA含量增大,先下降后上升。两步法制备的PMDA—BZD均聚PI薄膜脆性较大,而共聚PI薄膜由于ODPA的引入,成膜性和柔韧性明显改善。X—ray结果表明,不同程序升温速率,可得到不同有序程度的PI薄膜,即延长各个程序升温阶段处理时间,利于分子链运动,制备的薄膜具有更高的有序程度。
Homo-PAA co-PAA were prepared by polymerizing different molar ratios of PMDA and ODPA with BZD in NMP. Imidization in PAA solution at 180℃ and imidization of PAA coating films results PI powders and PI films respectively. For PI powders, with increasing of the proportion of ODPA incorporated in copolymer chain, the crystallinity gradually decreased and then increased. PMDA-BZD PI films were very brittle, but films obtained by copolymerization were all flexible. The results of X-ray show PI films which have different order degrees can be made by controlling the heating procedure, that is to say that prolonging time at each temperature makes molecular chain easy to move, so films have higher degree of order