Synthesis of imide-aryl ether benzoxazole random copolymers

Novel imide-aryl ether benzoxazole random or statistical copolymers were prepared by the reaction of a benzoxazole based-diamine with PMDA (pyromellic dianhydride) and ODA, an ether, to give the poly(amic-acid) in NMP. The key feature of the synthesis is the benzoxazole activated fluoro displacement in the preparation of the bis(amino) benzoxazole monomer. The copolymers prepared showed Tg's above 300°C and thermal stability comparable to that of polyimide. Tough ductile mechanical properties were also observed as indicated by both the high elongations (70-110%) and moduli (2300-2650 MPa). In addition, a reduction in the TEC was realized by the incorporation of the rigid benzoxazole containing comonomer.