Phenomenology of the dynamic moduli

Furthennore, by the same rationale, for shear thinning at lower shear rates k one predicts 

and x again being material-dependent parameters. Shear thickening is not considered. 

In a few systems, at very large frequencies or shear rates either a secondary relaxation or the high-frequency, perhaps polymer-modihed solvent viscosity or both are described by a functional form such as 

In other cases, at extremely large co it becomes apparent that the large-frequency behavior is a sum of two power-law decays 

We first consider the behavior of the dynamic storage modulus and the dynamic loss modulus. Colby, et a/. (15) report an extremely extensive series of measurements of the storage and loss moduli of a 925 kDa (M ) polybutadiene having a narrow molecular weight distribution (M /Mn 1.1 M /Mw 1-1). Solutions were made in the Theta solvent dioctylphthalate (DOP) at 12°C above the Theta temperature, and the good solvent phenyloctane (PO). Viscosities were reported at 15 volume fractions extending from extreme dilution 0.001) up to the melt full 

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