Viscosity of Low Molecular Weight Polymer Solutions over the Entire Concentration Range

摘要

An empirical equation is presented which describes the concentration dependence of the viscosity of low molecular weight (2000) poly (propylene oxide) solutions over the whole concentration range. The basis for the new equation is a consideration of the finite volume of the polymer molecules in solution. The new empirical equation fits the data extremely well over the whole concentration range for both a very good solvent (benzene) and a somewhat poorer solvent (methylcyclohexane). The hydrodynamic consequences of the thermodynamic interactions between polymer and solvent are reflected in the constants of the equation. A qualitative physical interpretation of this excluded volume equation is based on the limited interpenetration of the hydrodynamic polymer coils. Using the Debye or the Rouse-Bueche (DRB) formulation for the viscosity of a polymer solution, the proposed equation also describes the relative variation of the segmental (or bead) friction factor from infinitely dilute solution to bulk polymer. A Stokes' law interpretation of the friction factor is shown to be reasonable at infinite dilution. (Author)