GROUP-CONTRIBUTION LATTICE-FLUID EOS - PREDICTION OF LLE IN POLYMER-SOLUTIONS

The modified group-contribution lattice-fluid equation of state (GCLF- EOS) was applied to predict liquid-liquid equilibria (LLE) in polymer solutions. The modified GCLF-EOS is a group-contribution form of the e quation of state by Panayiotou and Vera based on the lattice-hole theo ry. Group contributions for the interaction energy and reference volum e were developed based only on the saturated vapor pressures and liqui d densities of low-molecular-weight compounds. For a mixture, group co ntributions for the binary interaction parameter were developed from t he binary vapor - liquid equilibria of low-molecular-weight compounds. This modified GCLF - EOS model can be applied to predict LLE behavior in polymer solutions with the same group-contribution parameters as u sed for predicting the vapor-liquid equilibria. The only input require d for the model is the structure of the molecules in terms of their fu nctional groups.