Preparation and properties of polyamides from 2,2′‐p‐phenylenebis‐5‐oxazolones with diamines

Novel phenylated polyamides having inherent viscosities in the range of 0.2–0.4 were prepared by the ring‐opening polyaddition of 2,2′‐p‐phenylenebis(4,4‐diphenyl‐5‐oxazolone) with aliphatic diamines in polar aprotic solvents. Similarly, unsubstituted polyamides were obtained from 2,2′‐p‐phenylenebis‐5‐oxazolone and both aliphatic and aromatic diamines. The phenylated polyamides were highly soluble in a wide range of solvents including tetrahydrofuran and dioxane, while the unsubstituted polymers showed limited solubility in the solvents. No marked differences in thermal stability between the phenylated and unsubstituted polyamides were noted, and all the polyamides began to decompose at around 250°C in both air and nitrogen.