Viscosity and density of poly(ethylene glycol) and its solution with carbon dioxide at 353.2 K and 373.2 K at pressures up to 15 MPa

Few viscosity and density data have been reported for CO2-poly(ethylene glycol) solutions, even though many vapor-liquid equilibrium data exist in the literature. In this work, viscosity and density of pure poly(ethylene glycol) (PEG, M=3000, 8300, 20,000 g mol(-1)) at atmospheric pressure were measured. Viscosities of PEG 3000 and PEG 8300 solutions with CO2 were measured with a torsional vibrating viscometer at 353.2 K and 373.2 K over the range of CO2 pressures from 5 MPa to 15 MPa. The densities of CO2-PEG solutions were calculated with the perturbed-chain statistical associating fluid theory equation of state. From shear viscosity measurements, PEG 3000 and PEG 8300 were confirmed to be Newtonian and PEG 20000 was confirmed to be non-Newtonian. The viscosity reduction ratio for PEG solutions saturated with CO2 was found to be independent of the PEG molecular weight (400 <= M <= 8300 g mol(-1)). A simple equation is proposed that can correlate CO2-PEG solution viscosity reduction ratio to within 0.08 in absolute units. The CO2-PEG solution viscosities could be correlated with free volume models to within 14% using the fitted value of CO2 occupied volume. (C) 2014 Elsevier B.V. All rights reserved.