Syntheses and properties of organosoluble polyimides based on 5,5′‐bis[4‐(4‐aminophenoxy)phenyl]‐4, 7‐methanohexahydroindan

Abstract

A series of organosoluble aromatic polyimides (PIs) was synthesized from 5,5′-bis[4-(4-aminophenoxy)phenyl]-4,7-methanohexahydroindan (3) and commercial available aromatic dianhydrides such as 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), 4,4′-oxydiphthalic anhydride (ODPA), 4,4′-sulfonyl diphthalic anhydride (SDPA), or 2,2′-bis(3,4-dicarboxyphenyl) hexafluoropropanic dianhydride (6FDA). PIs (IIIc–f), which were synthesized by direct polymerization in m-cresol, had inherent viscosities of 0.83–1.05 dL/g. These polymers could easily be dissolved in N,N′-dimethylacetamide (DMAc), N-methyl-2-pyrrolidone (NMP), N,N-dimethylformamide (DMF), pyridine, m-cresol, and dichloromethane. Whereas copolymerization was proceeded with equivalent molar ratios of pyromellitic dianhydride (PMDA)/6FDA, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA)/6FDA, or BTDA/SDPA, or ½ for PMDA/SDPA, copolyimides (co-PIs), derived from 3 and mixed dianhydrides, were soluble in NMP. All the soluble PIs could form transparent, flexible, and tough films, and they showed amorphous characteristics. These films had tensile strengths of 88–111 MPa, elongations at break of 5–10% and initial moduli of 2.01–2.67 GPa. The glass transition temperatures of these polymers were in the range of 252–311°C. Except for IIIe, the 10% weight loss temperatures (Td) of PIs were above 500°C, and the amount of carbonized residues of the PIs at 800°C in nitrogen atmosphere were above 50%. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 1681–1691, 1999