NON-NEWTONIAN FLOW OF STRUCTURED SYSTEMS. XXXI. VISCOSITY AND ELASTISITY OF THERMOTROPIC LIQUID CRYSTALS
Structural rheological model is used to describe the rheological behavior of thermotropic liquid crystals with low molecular weight. The change in viscosity at steady flow and dynamic moduli at shear oscillations is explained by the change in the structure of the non-oriented liquid crystal sample. The flow curves are well approximated by the generalized flow equation except the initial flow period with an unsteady structure. Dynamic modules and are well described by the structural rheological model equations except the small interval of low frequencies and the interval of high frequencies, where the transition to «pseudo-Newtonian» behavior occurs. The necessity to take into account the significant thixotropy of a substance for the correct interpretation of rheological data is shown.