Studies of Viscosity Coefficient and Expansivity Properties of Aqueous Solutions of Ethylene Glycol and Polyethylene Glycols at 293.15, 298.15 and 303.15 K and at Ambient Pressure

摘要

The relative viscosity coefficient (eta/eta(0)) and volumetric properties of mixtures of water with ethylene glycol (EG) and polyethylene glycols (PEGs) of molecular weights 400, 1000 and 4000 g.mol(-1) (PEG-400, PEG-1000 and PEG-4000) in the concentration range of similar to 0.01 to similar to 0.5 mol.kg(-1), or up to 0.1 volume fraction (phi(2)), have been measured at three temperatures (293.15, 298.15 and 303.15 K) and at ambient pressure. The data were subjected to analysis by applications of the Jone-Dole equation, Vand's equation with the viscosity parameters B and D, particle interaction coefficients (Q), Einstein-Simha factor (m), and hydration number (h) were determined at different temperatures. Using the density data, the limiting apparent molar volumes (phi(0)(V)) at different temperatures, and the limiting apparent molar expansivity (phi(0)(E)) at 298.15 K, were obtained. Positive values of the viscosity B coefficients were observed for all the studied systems; these decrease with increase in temperature, while the D coefficients are also necessary to represent the data, showing specific behavior depending upon the chain length of the polymeric molecules. The larger viscosity increments in excess of the Einstein-Simha volume contributions, and decreasing hydration numbers with increasing temperature, are attributed to the water structure-making effect, solute-solvent hydrogen bond interaction and the presence of hydrophobic interaction between the chain segments of the polymeric molecules. The resulting D coefficients and the virial coefficients are examined from the point of view of solute-solute association.