Corresponding states principle for newtonian viscosities-temperature effects

In the first part of the paper a superposition method for the polymer solution zero shear rate viscosity ηo as a function of concentration c is reviewed. The method was successful in numerous systems, but it partially failed in four, the worst case being polyisobutene in isooctane, where data were available over the full concentration range and molecular weights (MW) ranged from 900 to 2.5 × 106. It was postulated that the possible cause for this is either MW dependence of Tg which would result in a faster than expected increase in ηo for higher MW samples, or a difference in flow mechanism between the solutions at low and high concentration. In the second part, a new theory for the temperature effect on ηo is proposed. The theory permits linearization of ηo (T) results both for small molecules and for polymeric liquids. In systems where a transition occurs, the linearized plot shows a sharp break. The theory was extended to the concentration dependence of the polymer solution viscosity. It permits linearization of ηo (c) data, compensates for the MW dependence of Tg, and allows detection of transition points. The theory was tested on solutions of polyisobutene and polydimethyl-siloxane. In both cases, the data were superimposed on a single master curve.