Synthesis and characterization of new heat-resistance polymers based on N- (4-carboxy phenyl) trimellitimide and aromatic diamines

Five new aromatic poly(amide-imide)s (5a-e) were synthesized by direct polycondensation reaction of N-(4-carboxy phenyl) trimellitimide (3) with five aromatic diamines (4a-e) by using triphenyl phosphite in N-methyl-2-pyrrolidone (NMP) and pyridine at solution containing dissolved CaCl2. All of the polymers were obtained in quantitative yields with inherent viscosities between 0.29-0.40 dL/g. The resulting poly(amide-imide)s were characterized with elemental analysis, viscosity measurements, solubility test, FT-IR spectroscopy, thermo gravimetric analysis (TGA) and differential thermal gravimetry (DTG). All of the polymers were soluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethyl formamide (DMF), dimethyl sulfoxide (DMSO) at room temperature. N-(4-carboxy phenyl)trimellitimide (3) was prepared from the reaction of trimellitic anhydride (1) with 4- aminobenzoic acid (2) at room temperature and refluxing at 100-110°C in acetic acid as a solvent with a quantitative yield.