Thermal and mechanical properties of epoxy composite filled with binary particle system of polygonal aluminum oxide and boron nitride platelets

The increased heat generated in high-density electronics has intensified the search for advanced thermal management solutions. This urge has prompted fundamental studies on various filler-filled polymer composites with enhanced thermal performance. This research is intended to attain better understanding on the effect of particle sizes and geometry of fillers with different ratios of composition on the thermal and mechanical properties of hybrid composite system. It investigates the effect of combining polygonal aluminum oxide (Al2O3) and boron nitride (BN) platelets to enhance the thermal conductivity of epoxy composite. The surface of the two fillers was functionalized with aminopropyltriethoxysilane (KH550), thereby reducing the thermal interfacial resistance between filler and matrix. It was observed that there is no significant difference in the thermal and mechanical performance between BN1µm and BN5µm filler-filled composites. However, at filler loading of 30 wt%, the Al2O3 and BN1µm hybrid filler system (ratio 5:5) provided significant enhancement of maximum thermal conductivity of 0.57 Wm−1 K−1 compared to 0.17 Wm−1 K−1 that of neat epoxy. This synergistic effect results from the bridging of BN platelets between the Al2O3 particles facilitating the formation of effective thermal conductance network within the epoxy matrix.