The synthesis of carboxyl-terminated poly(ethylene glycol adipate) (CTPA) and amine-terminated poly(amide sulfone) (ATPS) based on the CTPA and 4,4′-diaminodiphenyl sulfone (DDS) is described. The products were characterized by IR and 13C-NMR spectroscopic analysis, nonaqueous titration, viscosity measurement, and solubility characteristics. The developed ATPS was incorporated as a modifier into the epoxy matrix and its effect was studied by DSC and DMTA. It was found that ATPS forms a compatible blend with epoxy and imparts flexibility to the epoxy matrix. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:901–907, 1997