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 polycondensationreaction of N-(4-carboxy phenyl) trimellitimide (3) with five aromatic diamines (4a-e) by usingtriphenyl phosphite in N-methyl-2-pyrrolidone (NMP) and pyridine at solution containingdissolved CaCl2. All of the polymers were obtained in quantitative yields with inherentviscosities between 0.29-0.40 dL/g. The resulting poly(amide-imide)s were characterized withelemental analysis, viscosity measurements, solubility test, FT-IR spectroscopy, thermogravimetric analysis (TGA) and differential thermal gravimetry (DTG). All of the polymers weresoluble in N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO) at room temperature. N-(4-carboxyphenyl)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 asolvent with a quantitative yield.