Thermal conductivity of epoxy composites containing 3D honeycomb boron nitride filler

Polymer matrix composites with excellent thermal management performance have emerged as remarkable materials in the realms of microelectronic devices and wireless communication technologies. However, achieving high thermal conductivity in most composites often requires a high filling load, which will compromise other desirable properties. Herein, utilizing physical foaming and vacuum infiltration methods, we introduce a 3D honeycomb composite consisting of surface-hydroxylated hexagonal boron nitride (OH-BN) and epoxy. The 3D OH-BN honeycomb foam in the composite features a lightweight design (0.33 g/cm3), high strength (7178 times its own weight) and prominent heat transfer performance. Significantly, these composites achieve notable thermal properties, including high through-plane thermal conductivity (2.073 W m−1 K−1) and relatively low thermal resistance (0.995 °C/W) at a reduced filling load (17.2 vol%). In comparison with pure epoxy, the through-plane thermal conductivity is enhanced by an impressive 894 %, while the thermal resistance is reduced to 1/9.4 of that observed in pure epoxy. Besides, the 3D honeycomb composites combine outstanding mechanical performance, low dielectric properties and excellent insulation, underscoring their potential in the field of thermal management applications in microelectronic devices, wireless communication systems and integrated circuits.