<i>N</i>‐methyl‐substituted aromatic polyamides

Abstract

Abstract A series of N ‐methyl‐substituted aromatic polyamides derived from the secondary aromatic diamines 4,4′‐bis(methylamino)diphenylmethane, 3,3′‐bis(methylamino)diphenylmethane, 4,4′‐bis(methylamino)benzophenone or 3,3′‐bis(methylamino)benzophenone and isophthaloyl dichloride, and terephthaloyl dichloride or 3,3′‐diphenylmethane dicarboxylic acid dichloride was prepared by high‐temperature solution polymerization in s ‐tetrachloroethane. Compared with analogous unsubstituted and partly N ‐methylated aromatic polyamides, the full N ‐methylated polyamides exhibited significantly lower glass transition temperatures ( T g ), reduced crystallinity, improved thermal stability, and good solubility in chlorinated solvents.