Rigid-Rod Polyamides and Polyimides Derived from 4,3‘‘-Diamino-2‘,6‘-diphenyl- or Di(4-biphenylyl)-p-terphenyl and 4-Amino-4‘‘-carboxy-2‘,6‘-diphenyl-p-terphenyl

Abstract

4,3‘‘-Diamino-2‘,6‘-diphenyl- or di(4-biphenylyl)-p-terphenyl (3a or 3b) and 4-amino-4‘‘-carboxy-2‘,6‘-diphenyl-p-terphenyl (6) were synthesized through pyrylium salts and used for the preparation of rigid-rod polyamides and polyimides. The polymers were characterized by inherent viscosity, elemental analysis, FT-IR, 1H-NMR, 13C-NMR, UV−vis, X-ray, differential scanning calorimetry (DSC), thermomechanical analysis (TMA), thermal gravimetric analysis (TGA) isothermal gravimetric analysis, and moisture absorption. They were amorphous. All polyamides as well as the polyimide derived from 3b and benzophenonetetracarboxylic dianhydride dissolved in polar aprotic solvents and H2SO4 98%. Polyamide prepared from 6 showed blue fluorescence in dimethylformamide solution. The Tgs of polyamides ranged from 235 to 285 °C. The polymers possessed excellent thermooxidative stability with no weight loss up to 379−417 °C in air.