Enhancing directional thermal conductivity in hexagonal boron nitride reinforced epoxy composites through robust interfacial bonding

Official URL: https://dx.doi.org/10.1002/pc.29136

Establishing a robust interfacial bond between hexagonal boron nitride (h-BN) plates and the epoxy matrix is essential for enhancing heat transfer, which is difficult because of h-BN's low-surface energy, tendency to clump together, and the chemical inertness of the epoxy matrix. This research shows different techniques for treating the surface of h-BN fillers by applying acids and thermal processes to activate the surface. The silanization process was used to increase the silane content on the surface of activated h-BN in order to make it more compatible with the epoxy matrix. X-ray photoelectron spectroscopy analysis revealed silicon peaks (Si2s peak at 150.1 eV and Si2p peak at 100.3 eV) in the spectrum of silane-treated samples. Heat treatment resulted in the production of more oxygen molecules on the shell of h-BN compared to the acid treatment. Here, the primary focus was on examining how surface treatment affects thermal conductivity (TC) performance in both in-plane and through-thickness paths. There was an increase in the epoxy's TC perpendicular to the plane, going from 0.21 to 0.47 (W/mK), showing a remarkable 123.8% enhancement by adding 10 wt% of silane-modified-thermal treated h-BN particles. The improvement resulted from effectively silanizing the exterior boundary of h-BN particles, enhancing connection and distribution in the epoxy matrix. Surface modification of h-BN-epoxy composites improves TC, leading to better heat conduction in thermal management systems, benefiting industries like aerospace, automotive, and energy systems. Highlights: Silanization of h-BN for better filler-matrix bonding leading to improved heat transfer Boosting thermal conductivity in the through-thickness direction with surface-modified h-BN Significant improvement in through-thickness thermal conductivity with treated h-BN. Thermal treatment of h-BN produced better oxygenation than acid treatment. Application in aerospace and automotive through improved heat transfer.