Phthalic Anhydride → Phthalamic acid

Participants

Reaction Conditions

Reaction Steps

The following example illustrates the synthesis of a phthalimide-terminatedimide oligomer with theoretical number average molecular weight of 9,000 g/mole. 3,4'-Oxydianiline (ODA) (85.0 mmole, 17.0209 g) and 1,3-bis(3-aminophenoxy)benzene (APB) (15.0 mmole, 4.3850 g) were dissolvedin N-methylpyrrolidinone (NMP) ( ~ 75 mL) in a flask equipped with a mechanical stirrer, condenser and nitrogen inlet. 3,3',4,4'-Biphenyl tetracarboxylic dianhydride (BPDA) (94.89 mmole, 27.9189 g) and phthalic anhydride (PA) (10.22 mmole, 1.5138 g) were slurried in NMP (~ 75 mL) and were added to the solution. Afterwashing with ~ 53 mL of NMP to provide a 20% solids content reaction, an exotherm of 10°-15° C. was observed. The exotherm quickly subsided and the reaction was stirred at 25° C. for 16 hours to form the phthalamide acid-terminated polyamide acid. The inherent viscosity (ninh) 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 hours. After cooling, a powder precipitated which was washed twice in water and dried to afford a yellow solid in high yield. The resulting phthalimide-terminated polyimide was insoluble in NMP, had a glass transition temperature 237° C. and melting endotherms of 324 and 350° C. A film cast from the polyamide acid solution and dried one hour each at 100°, 225°, and 371° C. had a Tg of 235° C. and a Tm at 324° C. and 350° C., and was tough.

Provenance & Evidence