Hybrid effects of exfoliated boron nitride nanosheet and carbon-based additives on thermally conductive polypropylene nanocomposites

Thermally conductive polymers are used in miniaturized electronic components across industries to dissipate heat, prevent overheating, and maintain device quality. In this work, hexagonal boron nitride was used as the main thermally conductive filler in polypropylene. A synergistic effect was achieved by introducing 1-D carbon nanotubes and 2-D graphene nanoplatelets. Different variations of these materials have resulted in improved thermally conductive nanocomposites. Exfoliated boron nitride nanosheets along with purified carbon nanotube-based polypropylene nanocomposites had the highest thermal conductivity and thermal diffusivity results (0.742 ± 0.007 W/mK and 0.412 ± 0.012 mm 2 /s, through-plane) with a 208.3 % improvement compared to pure polypropylene. Enhancements in the network structure were also observed in thermal camera images, which showed that the temperature of hybrid nanocomposites could rise from ∼28°C to 38.1°C in 4 minutes, while non-hybrid and pure nanocomposite samples reached ∼35.7°C and ∼34.6°C from ∼28°C at the same time, respectively. Morphological and physicochemical characterizations confirmed that hybrid nanocomposites had a modified bridging design, indicating an increase in the strength of the interconnections between fillers and the polymer network, as well as the presence of crystalline regions, which allowed phonons to pass through the pathway efficiently. The synergistic effect on the thermally conductive nanocomposites has promising results for electrically operating sustainable devices.