Magnetically assisted construction of Al2O3 platelets dual network and its excellent thermal conductivity in epoxy resin composites

Constructing three-dimensional thermally conductive networks in polymer matrix is a key strategy to improve the thermal management performance of electronic packaging materials. However, optimizing the thermal conductivity of the composite while retaining its electrical insulation properties still requires further structural design. Herein, the heat-transferring Al2O3 platelets dual network was constructed by using a simple compression moulding method combined with a magnetic alignment strategy. Al2O3@Fe3O4 was used for the magnetic orientation arrangement in the vertical direction of the laminated Al2O3 framework. And the obtained Al2O3/Al2O3@Fe3O4/Epoxy composites possessed satisfactory thermal conductivity. The thermal conductivity of the composites containing 34.63 vol% filler was as high as 2.30 W/mK (K‖) and 1.83 W/mK (K⊥), which were significantly higher by 945 % and 732 % compared to epoxy resin. In addition, the introduction of Al2O3@Fe3O4 in the composite promoted isotropic thermal conductivity and provided electromagnetic shielding properties.