Synthesis and characterization of poly(amideimide)s from 4-(p-carboxyphenoxy)phthalic anhydride and 4-(p-carboxybenzoyl)phthalic anhydride

A series of poly(amideimide)s were prepared by the reaction of two new anhydride acidchloride monomers with aromatic diamines. 4-(p-Carboxyphenoxy)phthalic anhydride was synthesized by nucleophilic displacement reaction of N-methyl-4-nitrophthalimide with p-hydroxybenzoic acid, followed by hydrolysis. The tricarboxylic acid was converted to the corresponding anhydride acidchloride. 4-(p-Carboxybenzoyl)phthalic anhydride was synthesized by Friedel–Craftʹs acylation of toluene with N-phenylphthalimide-4-carbonylchloride, which was then converted to anhydride acidchloride of 4-(p-carboxybenzoyl)phthalic acid. The monomers were characterized by IR and NMR. Several PAI were prepared by the reaction of these anhydride acidchloride monomers with aromatic diamines. The inherent viscosities of the polymers were in the range of 0.42–0.58 dL/g. All polymers were soluble in polar aprotic solvents. The polymers showed good thermal stability and Tg values were in the range of 226–269 °C. X-Ray diffractograms of polymers indicate amorphous nature of these polymers.