Synthesis and characterization of soluble aromatic polyamides from 2,5‐bis(4‐aminophenyl)—3,4‐diphenylthiophene and aromatic diacid chlorides

New soluble aromatic polyamides with inherent viscosities of 1.0–1.7 dL/g were prepared by the low temperature solution polycondensation of 2,5‐bis(4‐aminophenyl)—3,4‐diphenylthiophene, bis(4‐aminophenyl) ether, and aromatic diacid chlorides in N,N‐dimethylacetamide. The polyamides and copolyamides are generally soluble in amide‐type solvents. They have glass transition temperatures in the range of 280–325°C and showed no weight loss below 390°C on thermogravimetry curves in both air and nitrogen atmospheres.