Polyimides Derived from 3,3‘-Bis(N-aminophthalimide)

A novel diamine, 3,3‘-bis( N -aminophthalimide) (BAPI), was prepared from 3,3‘-bis( N -phenylphthalimide). Its structure was determined via IR, 1 H NMR, 15 N NMR, elemental analysis, and single-crystal X-ray diffraction analysis. A series of homo- and copolyimides were synthesized by a conventional one-step method in p -chlorophenol. The characteristic IR absorption bands of hydrazine-based imide groups were near 1780, 1750, 1350, 1100, and 730 cm -1 . The polymers showed good solubility in polar aprotic solvents and phenols at room temperature. The temperatures of 5% weight loss ( T 5% ) of the polyimides ranged from 495 to 530 °C in air. DMTA analyses indicated that the glass-transition temperatures ( T g s) of the polyimides were in the range 371−432 °C. These polymers had cutoff wavelengths between 350 and 400 nm. The polyimide films of 6FDA/BAPI and 4,4‘-HQPDA/BAPI were colorless; other films were pale yellow or yellow.