TOWARDS A BETTER MIXING OF 2 INCOMPATIBLE POLYMERS BY CASTING FROM SOLUTION WITHOUT COMPATIBILIZER

Blends of polystyrene/poly(oxyethylene) (PS/POE) and polystyrene/poly( methyl methacrylate) (PS/PMMA) have been obtained by casting from solu tion. Differential Scanning Calorimetry, Optical Microscopy, and Scann ing Electron Microscopy showed that two incompatible polymers can pres ent relatively good miscibility (formation of domains smaller than 5 m u m) when the solvent from which the films are obtained does not prese nt any noticeable selectivity towards the two polymers of the blends. An increase of the casting temperature increases the miscibility of PS and PMMA because the selectivity of the solvent used, towards these p olymers decreases with increasing temperature. On the contrary, an inc rease of the casting temperature in the case of the PS and POE mixture decreases their miscibility because the selectivity of the solvent us ed increases with increasing temperature. (C) 1998 John Wiley & Sons, Inc.