Three-dimensional MgO filler networking composites with significantly enhanced thermal conductivity

Recent considerable research efforts have been directed toward optimizing ceramic/polymer composite materials at the design stage, with a focus on enhancing thermal conduction pathways through distinct structures. This study introduces a simple process of adopting the template method followed by sintering to create a lightweight, self-supporting MgO framework with smooth-surfaced, highly thermally conductive MgO spheres. The segregated structure of inorganic ceramic particles significantly reduces thermal resistance and increases the thermal conduction path. Consequently, these composites exhibit notably higher thermal conductivity (6.61 W/mK) at a filler loading of 51.94 vol% compared to those with randomly dispersed particles. Additionally, 20.27 vol% 3D-MgO/epoxy composites with a thermal conductivity of 2.71 W/mK display a relatively low dielectric constant (3.78 at 1 kHz), only slightly higher than pure epoxy (3.39 at 1 kHz) with a thermal conductivity of 0.19 W/mK. This low dielectric constant is advantageous for electronic and electrical engineering applications. The study proposes an effective strategy for using MgO as an alternative to Al₂O₃ fillers in high-power-density electronic devices, making 3D-MgO/epoxy composites a promising next-generation thermally dissipating material for electronic devices.