Tailoring thermal conductivity and printability in boron nitride/epoxy nano- and micro-composites for material extrusion 3D printing

This study explores the design and characterization of boron nitride (BN)/epoxy nano- and micro-composites, utilizing material extrusion 3D printing as a powerful technique to align filler particles within the matrix and produce effective thermally conductive and electrically insulating adhesive materials with possible applications in electronics. Investigating the uncharted correlation between filler morphology, including both boron nitride microplatelets (BNMP) and boron nitride nanosheets (BNNS), processability by additive manufacturing (AM), and ink functionalities, BNMP proves more effective in boosting thermal conductivity, with an enhancement of up to 400%. Fillers, that can be highly oriented through material extrusion, contribute to achieving high glass transition temperature (up to 137 °C) and thermal resistance, expanding the inks’ applicability. Optimized inks demonstrate exceptional shape fidelity, enabling the fabrication of complex structures. The findings emphasize the crucial role of ceramic filler content and morphology in optimizing multifunctional 3D-printed materials' performance and tailoring their properties, offering insights for future innovations in electronic materials and manufacturing methodologies for thermal management applications. • Inks’ functional properties are tailored according to the boron nitride morphology. • 3D printable inks combine high thermal conductivity and low dielectric constant. • Multifunctional inks with high glass transition temperature are formulated. • Ceramic particles allow achieving outstanding shape fidelity in direct ink writing.