Properties of Modified Hexagonal Boron Nitride as Stable Nanofluids for Thermal Management Applications

Abstract

In this report, hexadecylamine (HDA) as a Lewis base was used to prepare exfoliated layers of modified hexagonal boron nitride h-BN (mh-BN) via two distinct solution and melt synthetic methods in order to prepare stable nanofluids based on mineral oil as the fluid. The synthesized structures were fully characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic-force microscopy (AFM). Obtained data shown that the highest content of covalently grafted HDA to the nanosheets surfaces was 5.5 wt % when reaction proceeded in NMP for 20 h. According to the results, the nanofluid prepared by the highest grafting content could enhance thermal conductivity of mineral oil up to 36.3% with low concentration of the nanofiller (0.05 wt %). The electrical and physical properties of the mentioned nanofluid were also investigated. According to the results, the dielectric loss reduced by increase in nanaofiller concentration indicating enhanced dielectric nature of nanofluid. The results revealed that the addition of low weight fraction of modified h-BN to the mineral oil improved its thermal conductivity as well as electrical features without suppressing other properties.