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 ðV ex mÞ and excess molar isentropic compression, Kex s;m, equal to ðoV ex m=opÞs 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 V ex m and Kex s;m 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 V ex m and Kex s;m data of the investigated systems.
