Quasi-chemical approximation for nonrandomness in the hole theory of polymeric fluids. 1. Equation of state behavior of pure components

The effect of nonrandomness is introduced in the Holey Huggins hole theory (a modified version of the Simha-Somcynsky theory) based on the quasichem. approxn. of Guggenheim. The resulting nonrandomness is dependent on the energetic interactions and is detd. by the so-called free vol. contributions typical of cell and hole theories. The theory offers an accurate description of exptl. equation of state data of polymers and small mols. A comparison with the random mixing analog of the present theory shows that the introduction of the quasichem. approxn. improves the accuracy of the description of exptl. data. [on SciFinder (R)]