Newtonian viscosity behavior of dilute to moderately concentrated solutions of cellulose acetate butyrate

The Newtonian viscosity behavior of dilute to moderately concentrated solutions of cellulose acetate butyrate in dioxane was investigated at different temperatures. The viscosity data were analyzed in terms of Martin's and Fedor's relationships and also generalized in terms of reduced variables. The rheological behavior of cellulose acetate butyrate solutions in the whole range of concentrations is determined by the parameter (K M C [n]). 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. ΔGv increases with concentration of polymer solution and is independent of temperature. The preexponential factor, A, related to activation entropy, decreases with concentration of polymer solution. The thermodynamic parameter of viscous flow for cellulose acetate butyrate (CAB)-dioxane solutions is indicative of moderately stiff structure for CAB in solutions.