| The observation that blending existing polymers can produce new and improved materials with the beneficial features of each component has focused attention on understanding the phase behavior of polymer blends because the resulting composites may form homogeneous phases or may be phase separated with a particular desirable morphology. While Flory–Huggins theory correctly predicts that liquid-state polymers generally do not tend to mix, its predictive ability for designing these new materials are rather limited. Thus, in order to rectify this deficiency in the theory, several approaches have been used to developmore ambitious theories, while experimental efforts have been devoted to devising various strategies for improving mixing including, for instance, the use of flow, as described in the article byClarke in this volume. Thus, progress in elucidating the factors affecting and promoting blend miscibility has benefited from strong interactions between experimental and theoretical groups, as emphasized by the articles herein. |
