Rheological studies of functional polyurethane composite with solid additives

The rheological dynamic characteristics of the functional polyurethane foam composite with solid additives (calcium iodate particles, aluminum flakes) were experimentally measured using an oscillatory rotational rheometer ARES-G2. Our previous studies demonstrated that the presence of the gas bubbles alters the rheology of the continuous liquid phase. The experimental tests results show that the apparent viscosity (the shear stress applied to a fluid divided by the shear rate) of the two-phase mixture increases with the concentration of the aluminum additive and decreases with the temperature rise. The rheological measurements showed that the functional foam exhibits a strong time-dependent and thixotropic (shear thinning) behavior. The rheological behavior of this composite can be described with the power law–generalized non-Newtonian fluid model. The apparent viscosity of the polyurethane increases with both the testing time (exponentially) and the solid content (polynomial) in the mixture. The measured rheological characteristics of the polyurethane-based functional foam will be helpful for material designers and developers.