Synthesis of polyamides by ring-opening polyaddition of bis-3,1-benzoxazin-4-ones with aliphatic diamines

Open-chain polyamides with inherent viscosities of 0.1–0.6 were prepared in nearly quantitative yields by the ring-opening polyaddition of combinations of six bis-3,1-benzoxazin-4-one monomers and two aliphatic diamines in polar aprotic solvents at 80°C or below. The polymerization carried out in dimethyl sulfoxide at 80°C was best for preparing high-molecular-weight polymers. These polyamides were generally soluble in polar aprotic solvents, m-cresol, and pyridine.