Behavior of Cold-Rolling Oil-in-Water Emulsions: A Rheological Approach

Abstract

The rheological behavior of oil-in-water emulsions has been studied as a function of oil concentration, shear strain rate, pressure and temperature. Results are discussed and correlated with several models which take into account the physical structure of emulsions. At low and medium shear rates and high concentrations, the emulsion’s behavior is non-Newtonian while under high shear rates, it becomes Newtonian. At ambient pressure, the viscosity of emulsions is weak and less temperature dependent than the base oil. The difference between the base oil and emulsion’s viscosity is less pronounced at high pressure. These tendencies are summarized by estimating the film formation ability of these lubricants. The oil concentration is the dominant parameter: if at low concentration the emulsions film formation ability is very weak, the results obtained at high concentration show a significant increase. This last point should be helpful to explain previous observations related to oil concentration variations inside the contact.