Theory of Non-Newtonian Flow. II. Solution System of High Polymers

The authors' theory developed in the preceding paper I is applied to solutions of polystyrene, polyisobutylene, X-518 GR-S rubber, and lime base grease with good agreement with experiment. The parameters, xn/αn and βn (see the abstract of the paper I), were calculated, and are tabulated; these parameters are proportional to the surface concentration and the relaxation time of the nth group of flow units, respectively. The effects of the molecular weights of polymers, concentration, solvent, and temperature on these parameters were studied. Our results establish the following facts: (1) The heterogeneity of flow units increases with increasing molecular weight. (2) In the range of low concentration, βn (relaxation time) is independent of concentration, while the areal concentration of non-Newtonian units increases more rapidly than proportional to the bulk concentration of a polymer. (3) A ``good'' solvent increases the concentration of non-Newtonian units, while the contrary is true for a ``poor'' solvent. (4) In poor solvent solutions, the concentration of non-Newtonian units increases with increasing temperature, while the concentration is independent of temperature in good solvents.