General molecular weight‐lowering side reaction in the thermal condensation of aromatic methyl esters with aromatic amines and hydrazides

Abstract

AbstractThe direct thermal condensation of aromatic methyl esters with aromatic amines and hydrazides was studied. Using model compounds, it was learned that N‐methylation of amines (both aromatic and aliphatic) and hydrazides is inherent at temperatures required for condensation polymerization. This side reaction prevents attainment of high molecular weight polyamides, polyhydrazides, or polyoxadiazoles from the corresponding difunctional aromatic monomers by heat alone. Reported catalysts for the condensation reaction do not prevent the side reaction.