09. Gupta, Ram B.; Prausnitz, John
M. Vapor-Liquid Equilibria for
Solvent-Polymer Systems from a Perturbed Hard-Sphere-Chain Equation of
State.
Abstract
Vapor-liq. equil. (VLE) for solvent-polymer mixts. at modest pressures are obtained from a perturbed hard-sphere-chain equation of state. This equation of state is the sum of a hard-sphere-chain term as the ref. system and a van der Waals attractive term as the perturbation. The ref. equation follows from the Percus-Yevick integral theory coupled with chain connectivity as described by Chiew. The effect of specific interactions, such as hydrogen bonding, is introduced through the proposal of Veytsman based on the statistical distribution of hydrogen bonds between donor and acceptor sites suggested by mol. structure. Calcd. and obsd. vapor-liq. equil. are presented for nonpolar, polar, and hydrogen-bonding solvent + homopolymer systems. Pure-component parameters (no. of segments per mol., segment-segment energy, and segment diam.) are obtained from pure-component properties: liq. d. and vapor pressure data for normal fluids and pressure-vol.-temp. data for polymers. A binary energy interaction parameter must be obtained from limited VLE data for each binary system; this parameter appears to be independent of temp. and compn. over a useful range. Theor. correlations and predictions are in good agreement with expt.
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