Viscosity and Density Measurements of Poly(ethyleneglycol) 200 and Poly(ethyleneglycol) 600 at High Pressures

Abstract

New measurements for the viscosity and density of poly(ethyleneglycol) 200 [PEG 200] and of poly(ethyleneglycol) 600 [PEG 600], at pressures up to 50 MPa, are presented. The temperature range of the measurements performed for PEG 200 was from 293 to 348 K and for PEG 600 was from 303 to 348 K. A vibrating wire viscometer operated in the steady-state mode was used to carry out the measurements with an estimated overall uncertainty less than U(η) = 0.02·η, for viscosities up to 68 mPa s, and less than U(η) = 0.026·η, for higher viscosities with a confidence level of 0.95 (k = 2). Complementary density measurements for both PEGs were performed in the same ranges of temperature and pressure as for the viscosity measurements, using an Anton Paar HP vibrating tube densimeter, with an estimated overall uncertainty of about U(ρ) = 0.002·ρ with a confidence level of 0.95 (k = 2). Moreover, pressure–viscosity coefficients were obtained for both PEGs. A method based on a dense hard-sphere fluid theory was used to correlate the viscosity data with the density, for both PEGs, with a deviation of the experimental results less than 1%. A modified Tait equation was used to correlate the density results with temperature and pressure.