MISCIBILITY AND KINETICS OF PHASE-SEPARATION IN BLENDS OF POLY(ETHYLENE OXIDE) AND POLY(ETHER SULFONE)

The miscibility and kinetics of phase separation in mixtures of poly(ethylene oxide) (PEO) and poly(ether sulphone) (PES) were studied. The mixture was found to have a lower critical solution temperature which, in contrast to observations by other authors, is higher than the glass transition temperatures of the mixtures. Using a light scattering technique the spinodal decomposition temperatures of the mixture were also obtained. The Cahn-Hilliard theory was found to be capable of predicting qualitatively the behaviour of phase separation in one mixture (PES/PEO, 10/90). Quantitative description of the spinodal decomposition behaviour would require knowledge of the effects of thermal fluctuation and of non-instantaneous temperature jumps on the experimental results.