SYNTHESIS AND CURING OF THERMALLY STABLE POLYAMIDES BEARING ENAMINO NITRILE UNITS

New polyamides has been prepared by reacting various aromatic diamines with a dicarboxylic acid (DCA) containing enamino nitrile units. The polycondensations were carried out in 1-methyl-2-pyrrolidone in the presence of lithium chloride utilizing triphenyl phosphite and pyridine as condensing agents. In addition, a model diamide was synthesized from the condensation of DCA with aniline. DCA was synthesized by reacting beta,beta'-dichloroterephthalyl dimalonitrile (DTD) with a double molar amount of 4-aminobenzoic acid using triethylamine as acid acceptor. Polyamides were characterized by i.r. and H-1-NMR spectroscopy as well as by inherent viscosity measurements. They were soluble in polar aprotic solvents. Upon curing at 300-degrees for 15 hr, they afforded heat resistant materials by rearranging, at least in part, the enamino nitrile segments to 4-aminoquinoline. Evidence for this rearrangement was obtained from the i.r., DTA and TGA data for the uncured and cured samples. The cured polyamides showed excellent thermal stability, being stable up to 377-389-degrees and affording an anaerobic char yield of 60-70% at 800-degrees.