NEW TECHNIQUE TO MEASURE HIGH-PRESSURE AND HIGH-TEMPERATURE POLYMER-SOLVENT VAPOR-LIQUID-EQUILIBRIUM

A new technique, based on absolute vapor pressure measurement, has bee n used to measure high-pressure polymer-solvent vapor-liquid equilibri a (VLE). VLE data are presented for binary mixtures of low density pol yethylene (LDPE) with n-pentane, 1-pentene, cyclopentane, 3-pentanol, 3-pentanone, propyl acetate, and isopropyl amine at temperatures of 15 0 degrees C and 200 degrees C, and solvent concentrations up to 50% by weight. The experimental data obtained are compared with the predicti ons from the UNIFAC-FV model and the modified GCLF-EOS model. Modifica tions are also considered to extend the applicability of UNIFAC-FV mod el to temperatures above the critical point of the solvent. The model predictions are in good agreement with the experimental data at high p ressures and temperatures, even above the critical temperature of the solvents. (C) 1997 Elsevier Science B.V.