Soluble Copolyimides Based on 2,3,5-Tricarboxycyclopentyl Acetic Dianhydride and Conventional Aromatic Tetracarboxylic Dianhydrides

Abstract

Soluble copolyimides based on 2,3,5-tricarboxycyclopentyl acetic dianhydride (TCA-AH)/aromatic tetracarboxilic dianhydrides/diamino diphenyl ether (DDE) were obtained. The maximum incorporation ratios of aromatic dianhydrides depend on flexibility of the dianhydrides. The ratios increase in the order of pyromellitic dianhydride (PMDA) (25 mol%), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) (50 mol%) and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) (65 mol%). The incorporation of conventional aromatic tetracarboxilic dianhydrides results in improvement of the thermal stability of soluble polyimides based on TCA-AH by the increment of aromatic components in polymer backbone, and the reduction of amount of a special monomer, that is TCA-AH.