Volumetric and Surface Tension Behavior of Aqueous Solutions of Polyvinylpyrrolidone in the Range (288 to 303) K

Experimental results have been obtained for the equilibrium liquid−vapor surface tension of the binary system composed of water + polyvinylpirrolidone (PVP). In this work we studied two different samples of PVP, at concentrations of (0.000002, 0.000018, 0.000102, 0.000499, 0.000999, 0.002003, 0.003018, 0.004021, and 0.005111) mass fraction of the polymer, at (288.15, 293.15, 298.15, and 303.15) K. The density has also been determined experimentally, for the same aqueous solutions in the same temperature range studied of surface tension, using two Anton Paar vibrating-tube densimeters (models DMA 60 and DMA 4500M). The values of the surface tension of the binary system decrease as the PVP concentration increases and as the temperature increases. The surface tension results of the binary system were correlated simultaneously as a function of temperature and PVP concentration. From the density results, the partial molar volume and the infinite dilution partial molar volume of the polymer have been calculated, which were correlated successfully with a general equation which takes into account the influence of the polymer concentration and temperature.