Experimental Evaluation of the Impact of Graphene Derivatives on the Rheological Properties of Ethylene Glycol

This work presents an experimental investigation into the rheological behavior of nanofluids prepared with four different types of graphene derivatives dispersed in ethylene glycol. The graphene-based nanostructures studied include nanoplatelets, nanoflakes, nanohorns, and nano-onions. These four derivatives were characterized by scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD). The experimental study focuses on the influence of shear rate and temperature on the rheological behavior of these nanofluids. For each nanocomposite, rheological measurements were performed using a rotational rheometer with cone-plate geometry, over a temperature range of 20 °C to 60 °C and shear rates from 1 s −1 to 1000 s −1 . The results demonstrate that the rheological properties are strongly influenced by the type of graphene derivative employed. Various rheological behaviors were observed, including shear-thinning and, in some cases, lubricating effects. Such results could be highly valuable for considering the use of these nanofluids in dynamic heat extraction applications. Finally, the dynamic viscosity-shear rate relationship was analyzed using the Carreau-Yasuda model, while the temperature dependence was described using the Arrhenius model.