A Thermal Conductive Epoxy Composite based on Spherical MgO Particles and Boron Nitride Sheets

The performance and life of high-power electronic devices are closely related to heat dissipation. Preparing high thermal conductivity, electrically insulating, polymer-based packaging materials for electronic devices is critical to achieving high heat dissipation. In the research described here spherical magnesium oxide (MgO) particles of various sizes and boron nitride (BN) sheets were used to prepare epoxy composites and their enhancement of heat transfer was investigated. In addition, the BN sheets were surface modified by γ-aminopropyltriethoxy silane (APTES) to increase interfacial compatibility between epoxy resin and BN, which enhanced the composite thermal conductivity. The composites with the highest thermal conductivity were made with 5 µm spherical MgO particles and BN sheets at a filler wt% ratio of 3:1 (MgO: BN). Using functionalized BN sheets enhanced the dispersion and compatibility of the 3:1 mixed filler. The thermal conductivity of the composite containing 45 wt% of the 3:1 mixed filler consisting of 5 µm spherical MgO particles and APTES functionalized BN sheets was 0.92 W/(m·K) as compared to 0.2 W/(m·K) for the epoxy resin alone.