Small-angle x-ray scattering studies of thermally-induced morphological changes in segmented polyurethane elastomers

The effect of temperature on the morphology of a series of polyether and polyester polyurethanes has been studied using small‐angle x‐ray scattering. Scattering curves were obtained in situ at high temperature (90 and 150°C) and also later at room temperature to study the effects of thermal history on the materials. In general, annealing improves the degree of phase separation and increases the hard domain size in the materials studied. Annealing improves the degree of phase separation in more compatible systems to a greater degree than in less compatible systems. Increased interfacial mixing is apparent in the materials studied in situ at high temperatures. Thicker interfacial regions are also present in the annealed material relative to the control.