A LOW-TEMPERATURE ROUTE TO POLYIMIDES

3-Dicyanomethylidene phthalide, a new phthalic anhydride analog, was synthesized by condensation of phthalic anhydride with malononitrile followed by treatment with phosphorus oxychloride. Several model reactions with aromatic amines and phenylhydrazine disclosed unexpected chemistry producing the corresponding imide in tetrahydrofuran or N-methylpyrrolidone solvent at room temperature. A difunctional pyromellitic dianhydride analog, 3,7-bis(2,2-dicyanomethylidene)pyromellitide, was also synthesized using similar reaction conditions. The polymerization reaction of this new monomer with oxydianiline and the subsequent curing reaction to polyimide are discussed.