Imide-aryl ether benzothiazole copolymers

Summary

Imide-aryl ether benzothiazole random copolymers were investigated. A new diamine containing preformed benzothiazole rings was prepared by a thiazole activated nucleophilic aromatic substitution reaction. The synthesis involved the reaction of 2,6-(bis(4-fluorophenyl))benzo[1,2,4,5]bisthiazole with 3-aminophenol in the presence of K ₂ CO ₃ in N-methylprrolidone (NMP) to afford bis(3-aminophenoxy)phenylbenzo [1,2,4,5]bisthiazole in high yield. This new diamine was readily purified and co-reacted with various compositions of 4,4′-oxydianiline (ODA) and pyromellitic dianhydride (PMDA) producing a series of imide-ary ether benzothiazole random copolymers. Films were cast and cured (350°C) to effect imidization, affording tough films with moduli significantly higher than PMDA/ODA polyimide. The thermal stability of the copolymers was good with thermal decomposition temperatures in the 480 to 510°C range, and the thermal expansion coefficients were lower than PMDA/ODA polymide and in the 25–30 ppm range.