Heat-sealable isomeric co-polyimide (CPI) films with enhanced atomic oxygen (AO) resistance and mechanical strength were synthesized from 2,3,3^′,4^′-oxydiphthalic anhydride (aODPA), 4,4^′-oxydianiline (ODA), and 2,5-bis [(4-aminophenoxy)phenyl]diphenylphosphine oxide (BADPO). We investigated how the molecular structure and diamine ratio affected the thermal properties, solubility, mechanical properties, AO resistance and heat-sealability. The diphenylphosphine oxide (DPO) side group decreased the CPI film mechanical strength and its higher ODA reactivity increased the molecular weight. At 10 mol% ODA in the aODPA-BADPO system, the CPI film exhibited increased tensile strength with no detriment to the AO resistance. Meanwhile, the CPI films demonstrated good heat-sealability indicated by a completely merged interface after heat sealing.

中文翻译：

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通过将醚键与二苯基氧化膦结合提高可热封同分异构共聚酰亚胺薄膜的耐原子氧性

由 2,3,3 ^' ,4'-氧二邻苯二甲酸酐 (aODPA)、^{4,4 '}-二苯胺 (ODA) 和 2,5-双 [(4-氨基苯氧基)苯基] 二苯基氧化膦 (BADPO)。我们研究了分子结构和二胺比例如何影响热性能、溶解度、机械性能、抗 AO 性和热封性。二苯基氧化膦（DPO）侧基降低了CPI膜的机械强度，其较高的ODA反应性增加了分子量。在 aODPA-BADPO 体系中，当 ODA 为 10 mol% 时，CPI 薄膜表现出增加的拉伸强度，而不会损害 AO 电阻。同时，CPI薄膜表现出良好的热封性，热封后界面完全融合。