Measurement and modeling of densities and sound velocities of the systems {poly(propylene glycol) + methanol, +ethanol, +1-propanol, +2-propanol and +1-butanol} at T = 298.15 K

Experiments have been performed at T = 298.15 K to measure the density and sound velocity of the systems {poly(propylene glycol) + methanol, +ethanol, +1-propanol, 2-propanol and +1-butanol} over the whole range of composition. From these measurements, values of the excess molar volume (Vmex) and excess molar isentropic compression, Ks,mex, equal to -(∂Vmex/∂p)s were calculated. The excess molar volume for all of these systems were found to be negative and decreases in magnitude as size of alcohol increases, except for 2-propanol solutions for which the magnitude of the excess volume is higher than that of 1-butanol solutions. Expressions for VmexandKs,mex of polymer solutions were obtained for the model of Flory–Huggins and the polymer non-random two liquid (NRTL) model. These expressions were used to fit the experimental VmexandKs,mex data of the investigated systems.