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

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.