Synthesis and Properties of New Poly(amide-imide)s Based on Imide Dicarboxylic Acid

Two kinds of imide dicarboxylic acid monomers, 4,4'-bis(trimellitimido) diphenyl ether (I) and p-trimellitimido-benzoic acid (II) were successfully synthesized from 4,4'-diaminodiphenyl ether and p-aminobenzoic acid with trimellitic anhydride respectively.and used to synthesize a series of new aromatic poly(amide-imide)s (PAIs) by the tri-phenyl phosphite-activated polycondensation method. The preparation of PAIs was carried out using triphenyl phosphate and pyridine system. The PAIs had inherent viscosities of 0.55-1.46 dL g(-1). PAT films were obtained by casting their N-Methyl-2-pyrrolidone (NMP) solution. Their cast films had tensile strengths ranging from 37.4 to 83.9 MPa. The glass-transition temperatures (measured by differential scanning calorimetry) were in the range of 265-310 degrees C. According to thermogravimetric analysis, the polymers were fairly stable up to temperature around 420 degrees C, and 10% weight losses in the temperature range of 474-550 degrees C in nitrogen, that showed good thermal stabilities of these polymers.