Aromatic poly(phenylene)4‐phenyl‐1,2,4‐triazoles

Abstract

Abstract High molecular weight poly( m ‐, p ‐phenylene)4‐phenyl‐1,2,4‐triazole has been prepared by the cyclocondensation reaction of aniline with high molecular weight poly( m ‐, p ‐phenylene) hydrazide in polyphosphoric acid (PPA). It is proposed that the cyclocondensation reaction proceeds through the attack of “free” aniline on either or both of two intermediate substrate polymers (a polyhydrazide phosphate and/or a protonated polyoxadiazole) to provide the desired polytriazole composition. The nature of the intermediate substrate polymer is determined primarily by the reaction temperature. Known model compounds containing the 4‐phenyl‐1,2,4‐triazole ring were prepared from model hydrazide compounds under cyclocondensation reaction conditions to demonstrate the validity of this synthesis approach to the polytriazoles. Thermally stable fibers and films having maximum zero strength temperatures of 465 and 490°C., respectively, have been prepared from formic acid solutions of poly( m ‐, p ‐phenylene)4‐phenyl‐1,2,4‐triazole. Thermogravimetric and differential thermal analyses of this polymer showed that the polymer was stable in nitrogen up to 512°C.