Morphology of bisphenol A polysulfone-polyoxypropylene segmented copolymers was inves-tigated by means of differential scanning calorimetry and transmission electron microscopy. Theresults show that the molecular weights of the hard and soft segments have a pronounced effect onthe morphology of these segmented copolymers

which may changr from three-phase to single-phasestructure depending on the size and the relahve size of the segments. Heat treatment will enhancethe process of phase separation

increasing the domain size of the dispersed phase.Results obtained by study on the dynamic mechanical properties of these copolymers well support the existence of three-phase morphological structure.