LOCAL COMPOSITION MODELS FOR LATTICE MIXTURES

A detailed comparison is made of several local-composition lattice mod els. The models considered include several popular activity coefficien t models: the Wilson equation, Guggenheim's quasichemical theory (GQC) , the nonrandom two-liquid theory (NRTL), and the universal quasichemi cal (UNIQUAC) theory. Also considered are three recently developed lat tice models: the Born-Green-Yvon (BGY) model, the nonrandom surface fr action (NRSF) model, and the Aranovich-Donohue (AD) model. Similaritie s and differences in the assumptions regarding the local compositions are examined. Detailed comparisons are made for both symmetric and asy mmetric monomer mixtures as well as for polymer/solvent mixtures with Monte Carlo simulations.