Phthalimide → Phthalamic acid

Participants

Reaction Conditions

Reaction Steps

The following example illustrates the synthesis of a phthalimide-terminated imide oligomer with theoretical number average molecular weight of 12,000 g/mole. 3,4'-Oxydianiline (3,4'-ODA) (36.00 mmole, 7.2089 g) and 1,3-bis(3-aminophenoxy)benzene (APB) (4.00 mmole, 1.1693 g) were dissolved in N-methylpyrrolidinone (NMP) (~35 mL) in a flask equipped with a mechanical stirrer, condenser and nitrogen inlet. 3,3',4,4'-Benzophenone tetracarboxylic dianhydride (BTDA) (38.38 mmole, 12.3673 g) and phthalic anhydride (PA) (3.240 mmole, 0.4799 g) were added to the solution with enough NMP to total 84.9 g (20% solids). The reaction was stirred at 25° C. for 6 h to form the phthalamide acid-terminated polyamide acid. The inherent viscosity (ηinh) of the phthalamide acid-terminated polyamide acid was 0.43 dL/g in NMP at 25° C. To imidize, toluene (40 mL) was added and the reaction was heated at 160° C. for 24 h. After cooling, a powder precipitated which was washed twice in water and dried ~230° C. in a vacuum to afford a yellow solid in high yield. The resulting phthalimide-terminated polyimide was insoluble in NMP and a glass transition temperature could not be detected while a melting endotherm peaked at 392° C. A film cast from the polyamide acid solution and dried 1 hour each at 100, 225, and 371° C. had a Tg of 252° C., a sharp Tm at 394° C. and was brittle.

Provenance & Evidence