Synthesis of polyphthalamides by ring‐opening polyaddition reaction of N,N′‐disubstituted bisphthalisoimides with diamines

The ring‐opening polyaddition reaction of N,N′‐disubstituted bisphthalisoimides with various diamines in amide‐type solvents at room temperature afforded polyphthalamides having inherent viscosity of up to 0.26 in excellent yields. Some of the polymers thus obtained are a new class of ordered alternating copolyphthalamides. These polyamides were soluble in polar aprotic solvents, as well as in acidic solvents. They showed relatively low melt temperature in the range of 120–220°C and further low level of thermal stability.