Rheological and Thermal Behavior of Xanthan Gum Nanofluids Based on Hexagonal Boron Nitride Under High-Pressure and High-Temperature Conditions

Abstract

Xanthan gum (XG) is a biopolymer widely used in different industries, such as food, cosmetics, oil, among others, which requires modifications in its properties. The present study aims to study the thermal and rheological properties of XG nanofluids based on oxidized hexagonal boron nitride (hBN-oxi) under high temperature and pressure conditions. The hBN-oxi was obtained through liquid exfoliation and then dispersed in the XG at different concentrations. The thermal conductivity of the nanofluids was investigated at different temperatures, and the addition of 6.0 wt% of hBN-oxi in the polymeric system increased thermal conductivity up to 12% at 70°C. The rheological behavior was obtained through steady-state and oscillatory flow measurements to evaluate the effect of hBN-oxi concentration under different temperatures and pressures. At higher concentrations, these nanostructures induced a yield stress in the fluid reaching a value of 12.8 Pa.s. Under high shear rates, the viscosity of the nanofluid decreased by only 16% at 80°C, indicating effective mitigation of temperature effect on viscosity. The pressure influence was also suppressed with the addition of these modified nanoparticles. This study highlights that well-designed formulations can significantly improve performance under extreme conditions.