Synergistic Improvement in the Thermal Conductivity of Hybrid Boron Nitride Nanotube/Nanosheet Epoxy Composites

Epoxy composites with excellent thermal properties are highly promising for thermal management applications in modern electronic devices. In this work, we report the enhancement of thermal conductivity of two different epoxy resins, Araldite's LY 564 (epoxy 1) and LY 5052 (epoxy 2) by incorporating multi-walled boron nitride nanotubes (BNNT) and boron nitride nanosheets (BNNS) hybrids as fillers. The highest thermal conductivity was observed at a loading of 1 wt% / 30 wt% of BNNT/BNNS hybrid, resulting in values of 2.6 Wm-1K-1 and 3.4 Wm-1K-1 respectively for each matrix, an increase of 10 to 17 times compared to the original epoxy. This improvement is attributed to the formation of a three-dimensional heat flow path formed through the intercalation of the nanotubes between the BNNSs. The thermal conductivity of the epoxy 1 and epoxy 2 composites improved by 940% and 1500% respectively, making them suitable as thermal interface materials in electronic packages requiring electrical resistivity.