Shear Rate Dependence of the Association of High Molecular Weight Macromolecules in Dilute Solution
Dilute solutions of flexible, high molecular weight macromolecules in nearly θ solvents have been demonstrated to have an increase of their relative viscosity above a critical shear rate, depending on the concentration1,2. In the same time, a non linear dependence of the reduced viscosity nsp/c is observed. Such a variation may be explained by an association process3,4,5,6. In this paper, we intend to apply the procedure described in our recent work5, at different shear rates to the following materials which have shown shear thickening2: Polystyrenes in decalin and polyethyleneoxide WSR301 in water. Calculations have been carried out in dimerization and multimerization cases. But only the dimerization appears to be compatible with the experimental results. The molecular weights of the polystyrene samples are listed in table II. We have made the assumption that the Huggins constant kH is nearly independent on the degree of association.
KeywordsShear Rate Association Constant High Shear Rate Relative Viscosity Wall Shear Rate
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