Abstract
Polyethersulfone has been shown to be miscible with phenoxy resin. Cast films were found to be clear and show a single, composition-dependent glass transition-Blends were found to phase separate on heating with a lower critical solution temperature around 185°C. The heat of mixing of low molecular weight analogs was small and negative, suggesting a favorable interaction between the polymers. Phase diagrams were simulated using the equation-of-state theory of Flory and co-workers and were found to agree closely with the observed behavior. The water vapor sorption of the blends was investigated, and this also suggested a weak favorable interaction between the polymers.