Stability of co-continuous polystyrene/poly(ether-ester) blends in shear flow

Co-continuous morphologies in a blend of poly(ether-ester) and polystyrene break up into a droplet/matrix morphology when subjected to a shear flow in a rheometer with a cone-plate configuration and are therefore not stable u nder shear. It is shown that the capillary number at these flow conditions is too small to maintain stable extended structures that are necessary for a co-continuous morphology. Go-continuity at such flow conditions is limite d to the point of phase inversion, contrary to the range of co-continuity u sually found after extrusion. (C) 1999 Elsevier Science Ltd. All rights res erved.