MISCIBLE BLENDS AND BLOCK COPOLYMERS - CRYSTALLIZATION, MELTING, AND INTERACTION

The effects of crystalline morphology and its kinetics on the melting point depression and thermodynamic interactions in miscible blends are theoretically analyzed and experimentally compared. Two compatible blends are studied: PEO/PMMA and PVF2/PMMA. As the concentration of amorphous PMMA increases, the thickness of folded-chain lamellae becomes thinner and the rate of crystallization slows down by orders of magnitude. These result in an increase in the concentration-dependent interaction parameter at their melting temperatures. From the morphological and thermal studies of PEO/PS block copolymers, we also find a great deal of similarities in the crystallization, melting, and interaction phenomena between this system and the miscible PEO/PMMA blends. © 1990, American Chemical Society. All rights reserved.