Synthesis, characterization, and curing of unsaturated polyamides derived from 2,6‐di(4‐carboxystyryl)pyridine and 2,6‐bis(4‐carboxybenzylidene) cyclohexanone

Abstract

AbstractTwo new series of heat‐curable polyamides were prepared utilizing the unsaturated dicarboxylic acids 2,6‐di(4‐carboxystyryl)pyridine (DCSP) and 2,6‐bis(4‐carboxybenzylidene)cyclohexanone (BCBC) as starting materials. They were prepared from the condensation of 4‐carboxybenzaldehyde with a half molar amount of 2,6‐dimethylpyridine or cyclohexanone, respectively. The dicarboxylic acids reacted with various aromatic diamines, utilizing triphenyl phosphite and pyridine as condensing agents, to yield polyamides. In addition, two model diamides were prepared by condensing the dicarboxylic acids with aniline. Characterization of starting materials, polyamides, and model compounds was accomplished by IR and 1H–NMR spectroscopy. The curing behavior of polyamides was investigated by DTA. Upon heat‐curing, the unsaturated polyamides were crosslinked through their olefinic bonds to afford insoluble, heat‐resistant resins. The thermal stability of the resins was evaluated by TGA and isothermal gravimetric analysis (IGA). The cured resins were stable up to 310–322°C in N2 or air and afforded anaerobic char yield of 57–69% at 800°C.