Viscosity Behaviour of Dilute and Moderately Concentrated Solutions. 1. Poly(vinylpyrrolidone) in 2-propanol

Abstract

The zero-shear viscosity of dilute to moderately concentrated poly(vinylpyrrolidone) solutions in 2-propanol were measured at different temperatures in the newtonian flow range. The viscosity data were analyzed in terms of Martin's and Fedor's equations. The viscosity-concentration data were generalized in terms of reduced variables. The relation between the K_M parameter for the rheological interaction and some characteristics of polymer solutions such as the flexibility of the PVP chain is discussed. The temperature dependence of viscosities was expressed by the Arrhenius-Frenkel-Eyring equation and the activation energy of viscous flow of polymer solutions (ΔGv) was calculated. It was shown that ΔGv increases with concentration and it is independent of the temperature.