New polyamides based on 2,5-bis[(4-carboxyanilino) carbonyl] pyridine and aromatic diamines: Synthesis and characterization

Seven new polyamides 6a-g were synthesized through the direct polycondensation reaction of 2,5-bis[(4-carboxyanilino) carbonyl] pyridine 4 with seven derivatives of aromatic diamines 5a-g in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The polycondensation reaction produced a series of novel polyamides containing pyridyl moiety in the main chain in high yield with inherent viscosities between 0.32-0.72 dL/g. The resulted polymers were fully characterized by means of FTIR spectroscopy, elemental analyses, inherent viscosity, and solubility tests. Thermal properties of these polymers were investigated by using thermal gravimetric analysis and differential thermal gravimetric. All the polymers were soluble at room temperature in polar solvents, such as N,N-dimethyl acetamide, N,N-dimethyl formamide, dimethyl sulfoxide, and N-methyl-2-pyrrolidone. 2,5-Bis[(4-carboxyanilino) carbonyl] pyridine 4 as a new monomer containing pyridyl moiety was synthesized by using a two-step reaction. At first 2,5-pyridine dicarboxylic acid 1 was converted to 2,5-pyridine dicarbonyl dichloride 2. Then diacid 4 was prepared by condensation reaction of diacid chloride 2 with p-aminobenzoic acid 3. (C) 2008 Wiley Periodicals, Inc.