Synthesis and properties of imide-aryl ether 1,2,4-triazole random copolymers

New imide-aryl ether copolymers containing a 1,2,4-triazole heterocyclic unit were prepared, and their structural, mechanical and thermal properties were studied. These copolymers contain an aryl ether 1,2,4-triazole linkage, which was incorporated into a semi-rigid backbone by the reaction of new 1,2,4-triazole diamines with 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA). The 1,2,4-triazole diamines were prepared through a nucleophilic aromatic substitution reaction of 3,5-bis(4′-fluorophenyl)-4-phenyl-1,2,4-triazole with either 3- or 4-aminophenol in the presence of K2CO3 in a polar aprotic solvent mixture to afford 3,5-bis(3′-aminophenoxyphenyl)-4-phenyl-1,2,4-triazole and 3,5-bis(4′-aminophenoxyphenyl)-4-phenyl-1,2,4-triazole, respectively. The monomers were reacted with PMDA or co-reacted with ODA and PMDA to synthesize the desired poly(amic acid)s. Films were cast and cured at 350°C to effect imidization, producing films with good mechanical properties. © 1993.