【摘要】 通过均苯四甲酸二酐(PMDA)分别与联苯二胺 (DABP)、3, 3’-二甲氧基联苯胺 (DMOB)和 3, 3’-二羟基-4, 4’-二氨基联苯(HAB)的缩合及相应聚酰胺酸的热环化失水酰亚胺化反应, 制备了联苯均酐型聚酰亚胺(PI).TGA和DSC研究表明,邻甲氧基和邻羟基使PI的开始分解温度和不同失重百分比的温度降低.其耐热性为DABP-PMDAPI>DMOB-PMDAPI>HAB-PMDAPI.发现DMOB-PMDAPI和HAB-PMDAPI的热行为相似,其热分解过程可能涉及重排成聚苯并噁唑(PBO)的类似反应.更多还原

【Abstract】 Poly(biphenylenepyromellitimide)s with or without ortho-substituted groups are prepared by polycondensing pyromellitic dianhydride (PMDA) with 4,4’-Diamino biphenyl (DABP), 3,3’-Dimethoxy benzidine (DMOB), and 3,3’-Dihydroxy-4,4’-Diamino biphenyl (HAB), and then are imidized by thermally cyclodehydrating the corresponding poly(amic acid)s. Their TGA and DSC studies show that the o-hydroxy or o-methoxy substituents decrease the specific temperatures at which the PIs start decomposition and the temperatures losing different weight percent. The heat resistance is DABP-PMDA PI> DMOB-PMDA PI> HAB-PMDA PI. It is found that the heat behaviors of DMOB-PMDA PI and HAB-PMDA PI are similar, which suggests a similar reaction mechanism of rearrangement to polybenzoxazole (PBO) during their thermal decomposition.更多还原