Liquid‐Liquid Phase Separation in Multicomponent Polymer Systems. XXIV. Thermodynamics of Polymer Blends

Within its own scope the classic Flory‐Huggins‐Staverman theory for macromolecular systems can easily be extended so as to deal with lower consolute miscibility behaviour as such, as well as in combination with upper consolute miscibility in the same system. A further improvement is achieved if the different numbers of nearest‐neighbour contacts the various repeat units and molecules can make are accounted for. Strong bimodality of lower consolute cloudpoint curves seems to call for the introduction of free‐volume terms. Some consequences of such bulk mixture terms are discussed briefly.