Enthalpies of solution of polyvinylpyrrolidone (PVP, molecular weight average, Mw ＝ 1 × 104) in water, alkanol (n ＝ 1 ～4) and 1-methyl-2-pyrrolidone (NMP) were measured at 298.15 K using newly constructed calorimeter to investigate the solvation behavior of PVP in those solvents. Enthalpy of solution of PVP in water is exothermic. Enthalpies of solution of PVP in other solvents are smaller than uncertainty of calorimeter. Densities and sound velocities were also measured in same series of solution to calculate partial specific volumes at infinite dilution, Vw,2 ∞, partial specific isentropic compressions at infinite dilution, Ks,w,2 ∞, of PVP of different molecular weight. And viscosity was also measured to evaluate specific viscosity, ηSP, of these solutions. Vw,2 ∞ of PVPs in water is larger than Vw,2 ∞ of PVPs in alkanols, and Ks,w,2 ∞ of PVPs in water is zero. For the alkanol solutions, Vw,2 ∞, Ks,w,2 ∞ and ηSP of PVPs increase with increasing number of carbon atoms in the alkanol molecules. Vw,2 ∞ in NMP shows the largest value among all systems investigated. Positive values of Ks,w,2 ∞ mean that solvent molecule surrounding PVP are easily compressible, for NMP system.
Keywords:polyvinylpyrrolidone; enthalpy of solution; partial specific volume; partial specific isentropic compression; specific viscosity