Improving thermal conductivity of epoxy composite by three-dimensional filler network constructed with two different diameters aluminum nitride and cellulose nanofiber

With the rapid advances in electronic technology, efficient thermal dissipation has become a critical concern, and as a result, polymer composites are being utilized as various industrial areas. However, the relatively low thermal conductivity of polymers is a limitation that must be overcome. Hence, in this study, we prepared a 10-µm aluminum nitride (AlN)@cellulose nanofiber (CNF) filler through a ball milling method. Following this, a 3D cellulose foam was fabricated using the AlN@CNF and a 4-mm aluminum nitride, which was obtained through freeze drying. Finally, the 3D foam was vacuum infiltrated with epoxy (EP) resin to fabricate the 3D-AlN@CNF₁/AlN₁/CNF/EP composite. Specifically, the 3D foam provided a continuous and efficient heat pathway, which increased the thermal conductivity from 0.2 to 1.88 W/mK with a 46.5 v/v% AlN loading. Additionally, the tensile stress and tensile strain were 34.8 MPa and 4.6%, respectively. Overall, these results suggest that the proposed 3D-AlN@CNF/AlN/EP composite is a promising material for efficient thermal management in various electronic devices.