The rheological properties of the carboxymethylcellulose (CMC) – water, hydroxyethyl cellulose (HEC) – DMF and hydroxypropyl cellulose (GPC) – DMSO and GPC – ethanol have been investigated in the dynamic conditions with a frequency scan and in a stationary shear. The concentration dependences of activation enthalpy of viscous flow for HEC and CMC solutions were obtained. It is established that the nature of GPC solutions varies with the increase in concentration from Newtonian to non-Newtonian: the stationary and dynamic viscosity of fluids decrease when the shear rate and frequency increase. Solutions of the GEC are viscoelastic liquids the concentration larger a certain one. For the first time the calculations of the activation parameters of the solution flow from data obtained by essentially different methods are compared. It is shown that the magnitude and the nature of the activation enthalpy of viscous flow are determined by the phase composition of the system, i.e. the dependence of the activation enthalpy on the concentration allows to determine the boundaries of the "corridor" in which the isotropic and anisotropic (LC) phase coexist. The concentration dependences of the dynamic modules are correlated with those for the activation enthalpy of the flow.
|Date of Award||2017|
|Supervisor||Елена Витальевна Русинова (Supervisor)|