Semi-empirical theory of the viscosity of moderately dilute polymer solutions

Abstract

Abstract:The viscosity r/ of moderately dilute polymer solutions is formulated on the postulates that in this concentration region r/is governed by the domain volume per polymer segment and the "noddle effect" due to entangling chains. The former is treated semi-molecular theoretically, and the latter entirely phenomenologically. All the parameters involved in the theory can be estimated from appropriate dilute solution data as well as the asymptotic molecular-weight dependence of t/ at different concentrations. It is shown that the theory describes almost quantitatively the experimental data obtained by Hamada and Adam and Delsanti for polystyrene in benzene and cyclohexane. Part of these data reveals the breakdown of the semidilute solution approximation used in the theory.

Rheology and Rheological Measurements

“…For a concentrated solution, properties above and below M c may be quite different. For example, the dependence of viscosity on molecular weight, which is much greater in concentrated than in dilute solutions, changes from a value on the order of unity below M c to one of 3.4-3.5 above M c (37,39,40). That is, ¼ KM below M c and ¼ KM 3.4-3.5 above M c .…”