synopsisHigh molecular weight poly(m-,pphenylene)4phenyl-1,2,~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 polyhydraside phosphate and/or a protonated polyoxadiazole) to provide the desired polytriazole composition. The nature of the intermediate substrate polymer is determiped 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 polytriazole8. Thermally stable fibers and f i l m s having maximum zero strength temperatures of 465 and 4O0C., respectively, have been prepared from formic acid solutions of poly(m~,pphenyiene)4-phenyl-l,2,4triazole. Thermogravimetric and differential thermal analyses of this polymer showed that the polymer was stable in nitrogen up to 512OC.

A chemical cyclocondensation reaction process has been developed to convert the easily prepared poly(phenylene)hydrazide to the corresponding high molecular weight poly‐3,5‐(m‐, p‐phenylene)‐4‐phenyl‐1,2,4‐triazole. Polytriazole fibers have been spun from formic acid solutions utilizing both wet and dry spinning techniques. These fibers develop a high degree of orientation and crystallinity on stretching at temperatures of 300°C. and higher. Such fibers retain approximately 30% of their initial breaking strength at a temperature of 300°C. and are not seriously degraded on exposure to elevated temperatures for prolonged periods. The fiber dimensional stability at temperatures above the glass transition temperature of 260°C. for the amorphous polymer was found to be directly related to the fiber orientation and crystallinity. The ease of fabrication and thermal stability of the phenylene triazole polymer makes this material potentially attractive for other end‐use applications such as films, protective coatings, and electrical insulation.