Simple Protein Foaming-Derived 3D Segregated MgO Networks in Epoxy Composites with Outstanding Thermal Conductivity Properties

The miniaturization and high-power density of electronic devices present new challenges for thermal management. Efficient heat dissipation in electrically insulating packaging materials is currently limited by the thermal conductivity of thermal-interface materials (TIMs) and their ability to effectively direct heat toward heat sinks. In this study, MgO-based composites with high thermal conductivities are fabricated to achieve excellent thermal performances by optimizing the heat-transfer path. These composites are produced using a protein foaming method, which effectively forms interconnected ceramic-filler networks. Additionally, the liquid phase formed during the sintering of MgO enhances the bonding with the epoxy matrix, thereby improving the thermal conductivity of the composites. As a result, the composites with 54.64 vol% MgO achieve a high thermal conductivity of 17.19 W m⁻¹ K⁻¹, which is 101 times higher than that of pure epoxy, 3.7 times higher than that of randomly dispersed composites, and even superior to that of nitride-based composites. Moreover, the composites also exhibited a low thermal-expansion coefficient (27.76 ppm °C⁻¹) and high electrical-insulation strength (51.51 kV mm⁻¹), ensuring good thermal and electrical performance for electronic-packaging applications. The strategic design of the TIM microstructures for effectively directing heat offers a promising solution for efficient thermal management in integrated electronics.