Steady-shear rheology and activation thermodynamics of the interpolymer complex between nonionic polymeric surfactant and hydrophobically modified polyacrylic acid in propylene glycol–water mixture

Abstract

Rheology of the individual polymer solutions and complex polymer mixtures was studied in the temperature range from 30 to −20 °C. Based on the obtained data steady-shear flow properties and thermodynamic parameters of a viscous flow were calculated. Exploiting the flow parameters such as the flow behavior index it was demonstrated that addition of synthesized anionic polymeric surfactant—polyvinyl octanal (PVO) to the polyelectrolyte solution enhanced pseudoplasticity of the obtained liquids at low temperatures. Along with that, the anomalous behavior of the activation enthalpy and activation entropy as a function of temperature was observed for the polyelectrolyte solutions containing PVO. Thus, it was shown that relatively high initial values of ΔH A diminish sharply with an increase in temperature and TΔS A values decrease dramatically below 0 °C. The obtained results were in line with the concept of the critical temperature observed for the strongly associated polymeric systems in water–glycol mixtures. In the light of the findings it was assumed that specific interpolymer association occurs at low temperatures resulting in consequent increase in the values of apparent viscosity and pseudoplasticity of the studied polymeric liquids. It was also suggested that studied system is well suited for the formulation of the thickened aircraft deicing fluids.