Cyano-substituted polyamides and polyimides prepared from 2,6-bis(3-aminobenzylidene)-1-dicyanomethylene-cyclohexane

Cyclohexanone was condensed with 3-nitrobenzaldehyde in the presence of dry HCl as catalyst to afford 2,6-bis(3-nitrobenzylidene)cyclohexane. The condensation of the latter with malononitrile yielded 2,6-bis(3-nitrobenzylidene)-l-dicyanomethylene-cyclohexane that was hydrogenated to the corresponding diamine. The latter was used as a reagent for preparing various unsaturated polyamides and polyimides bearing dicyanomethylene segments. In addition, a model diamide and diimide were synthesized. The polymers were soluble in polar aprotic solvents and certain strong inorganic and organic acids. They were crosslinked upon heating at 300°C for 20 hr. The crosslinked polymers were stable up to 377–408°C in N₂ or air and afforded anaerobic char yields of 65–70° at 800°C.