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. 4,4'-Oxydianiline (4,4'-ODA) (8.00 mmole, 1.6020 g) and 1,3-bis(3-aminophenoxy)benzene (APB) (32.00 mmole, 9.3547 g) were dissolved in N-methylpyrrolidinone (NMP) (~35 mL) in a flask equipped with a mechanical stirrer, condenser and nitrogen inlet. Pyromellitic dianhydride (PMDA) (38.51 mmole, 8.3994 g) and phthalic anhydride (PA) (2.980 mmole, 0.4414 g) were added to the solution with enough NMP to total 79.2 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 0.36 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 had a glass transition temperature 218° C. and a small Tm at 331° C. A film cast from the polyamide acid solution and dried 1 hour each at 100, 225, and 371° C. had a Tg of 240° C. and was tough.

Provenance & Evidence