Non-Newtonian Flow of Structured Systems. XV. Shear Vibrations

Abstract
A structural rheological model is used to describe the rheological behavior of polymer and disperse systems under oscillatory testing. It is suggested that the effective rate under shear vibrations affects the structure of the system similarly to the shear rate at stationary shear flow. The equations obtained for the steady shear flow were converted for the description of the viscoelastic behavior of structured systems in the high frequency region. The viscous modulus G'(ω) and the elastic modulus G'(ω) are represented by equations:

and

. These equations describe well the experimental data at high frequencies. At low frequencies, the dynamic viscosity reaches a plateau, similar to the conventional shear viscosity. The experimental values of the elastic modulus G'(ω) are located below the theoretical curve, these results can be described by the empirical dependence G'^1/2 = g₀''(ω^1/2-ω₀^1/2).

Keywords: viscoelastic system, dynamic measurements, structural rheological model, elastic modulus, viscous modulus