Synthesis of aromatic polyimines by the condensation of aromatic dialdehyde and diamine

Film-forming aromatic polyimines were prepared by low temperature solution polymerization of aromatic dialdehyde and aromatic diamine usingm-cresol. The polymerization proceeded rapidly to give high molecular weight polyimine solutions. Fibrous polymers were precipitated by pouring the solutions into anhydrous methanol. Lemon yellow-to-orange films were cast in situ from the reaction solutions. The polymers showed typical C=N stretching absorption near 1620 cm^?1 in infrared spectra and had high glass transitions of over 200 ?C but showed low crystallinity.