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

A series of organosoluble aromatic polyimides (PIs) was synthesized from 5, 5 '-bis [4-(4-aminophenoxy)phenyl] -4,7-methanohexahydroindan (3) and comme rcial available aromatic dianhydrides such as 3,3 ',4,4 ' -biphenyltetracar boxylic dianhydride (BPDA), 4,4 '-oxydiphthalic anhydride (ODPA), 4,4 '-sul fonyl diphthalic anhydride (SDPA), or 2,2 '-bis(3,4-dicarboxyphenyl) hexafl uoropropanic dianhydride (6FDA). PIs (IIIc-f), which were synthesized by di rect 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-c resol, and dichloromethane. Whereas copolymerization was proceeded with equ ivalent molar ratios of pyromellitic dianhydride (PMDA)/6FDA, 3,3 ',4,4 '-b enzophenonetetracarboxylic dianhydride (BTDA)/6FDA, or BTDA/SDPA, or 1/2 fo r 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 polyme rs were in the range of 252-311 degrees C. Except for IIIe, the 10% weight loss temperatures (T-d) of PIs were above 500 degrees, and the amount of ca rbonized residues of the PIs at 800 degrees C in nitrogen atmosphere were a bove 50%. (C) 1999 John Wiley & Sons, Inc.