Synthesis and properties of poly(ether imide)s based on a benzonorbornane bis(ether anhydride)

A novel bis(ether anhydride) monomer, 3,6-bis(3,4-dicarboxyphenoxy)benzonorbornane dianhydride, was synthesized from the nitro displacement of 4-nitrophthalonitrile with 3,6-dihydroxybenzonorbornane in the presence of potassium carbonate, followed by the alkaline hydrolysis of the intermediate bis(ether dinitrile) and the cyclodehydration of the resulting bis(ether diacid). A series of poly(ether imide)s bearing pendant norbornane groups were prepared from the bis(ether anhydride) with various aromatic diamines via a conventional two-stage process that included ring-opening polyaddition to form the poly(amic acid)s followed by thermal imidization to the poly(ether imide)s. The inherent viscosities of the poly(amic acid) precursors were 0.81-1.81 dL/g. The poly(ether imide) with m-phenylenediamine as a diamine showed good organosolubility. Most of the cast poly(ether imide) films have had high tensile strengths and moduli. The glass-transition temperatures of these poly(ether imide)s, except for those from rigid p-phenylenediamine and benzidine, were recorded between 211 and 246 degreesC by differential scanning calorimetry. The softening temperatures of all the poly(ether imide) films stayed within 210-330 degreesC according to thermomechanical analysis. No polymers showed significant decomposition before 500 degreesC in a nitrogen or air atmosphere. A comparative study of the properties with the corresponding poly(ether imide)s without pendant substitutents was also made. (C) 2002 Wiley Periodicals, Inc.