TEMPERATURE AND COMPOSITION DEPENDENCE OF VISCOSITY .2. TEMPERATURE-DEPENDENCE OF VISCOSITY OF PROPYLENE CARBONATE-DIMETHOXYETHANE MIXTURES

The application of the currently used equations for the reproduction o f the temperature dependence of viscosity eta of binary solvent mixtur es of propylene carbonate (PC) and dimethoxyethane (DME) favors the ch oice of the Vogel-Fulcher-Tammann (VFT) equation using the ideal glass transition point as the reference temperature T-o for the estimation of free and blocked (inaccessible) volumes. Reduced plots show that th e free volumes as obtained from the VFT equation mainly determine the viscosities of the liquid mixtures; the blocked volumes V-x(T-o) = V-o (x: mole fraction of PC) show ideal behavior. The effect of negative excess volumes V-E on viscosity studied in the preceding paper is exam ined in comparison with the effect of a temperature decrease. The equa l signs of eta(E) and V-E can be explained by referring the viscositie s to the reference temperature T-o.