Synthesis and characterization of polyester‐imides from imidodicarboxylic acid monomers and ethylene glycol

Two monoimidodicarboxylic acids and four diimidodicarboxylic acids were synthesized from trimellitic anhydride and amino compounds, viz., glycine, p ‐aminobenzoic acid, 4,4'‐diaminodiphenyl sulfide, 4,4'‐diaminodiphenyl ether, 4,4'‐diaminodiphenyl methane, and 4,4'‐diaminodiphenyl sulfide, and characterized by IR and 1 H‐NMR spectroscopies and melting‐point determination. These functional monomers were condensed in N ‐methyl‐2‐pyrrolidone solvent with ethylene glycol by a transesterification reaction to obtain the novel polyester‐imides with backbones of alternate imide‐ester linkages or imide‐imide‐ester‐ester linkages with SO 2 , O, CH 2 , or SS bridges in between. All the polymers were characterized by IR and 1 H‐NMR spectroscopies, X‐ray diffraction, solution viscosity, solubility and solubility parameters, and differential thermal analysis. Most of the polymers possess amorphous structure and fairly high decomposition temperatures (450–485°C). These polymers having solubility parameters in the range δ 11.44–11.85, as determined by the group contribution technique, are soluble at room temperatures in aprotic polar solvents. © 1993 John Wiley & Sons, Inc.