Join us at the International Thermal Conductivity Conference (ITCC) and the International Thermal Expansion Symposium (ITES).
The authors present a review of the thermal properties of graphene, and present one example of a practical application of graphene in thermal management, as an additive to phase change materials. It was found that the use of liquid-phase-exfoliated graphene as a filler in phase change materials has potential to enhance the thermal management in high-power battery packs. The results also indicated that graphene had the potential to outperform metal nanoparticles and other carbon allotropes as a filler in these materials.
The authors have presented a literature review on computational and experimental studies on the thermal conductivity of nanostructure enhanced phase change materials (nePCMs). It was found that a wide range of nanostructures have been investigated, from carbon nanostructures and carbon nanotubes to metal and metal oxide nanoparticles. The carbon nanostructures and nanotubes were found to generally enhance the thermal conductivity of the PCMs by a greater amount than metal or metal oxide nanoparticles due to their high aspect ratio in comparison to the spherical or agglomerated nanoparticles.
The effects of particle size/shape, base fluid, and volumetric concentration on the thermal conductivity of nanofluids has been studied. It was found that decreasing the particle size leads to an increased thermal conductivity, and that using water as a base fluid led to the greatest enhancement of thermal conductivity. The effects of gravity, Brownian motion, and thermophoresis on particle motion were also investigated and it was found that gravity had a significant impact on the thermal conductivity of these nanofluids due to rapid settling of the nanoparticles, resulting in a decreased thermal conductivity.
The properties of carbonized lignin nanoparticles were investigated to determine if this material could be used as an environmentally-friendly alternative to carbon black. The observed surface area of the carbonized lignin was found to be higher than that of carbon black because the powder is highly porous. The lignin nanoparticles were able to be produced in such a way as to give a similar size as carbon black nanoparticles, with a similar carbon purity. The thermal conductivity of carbonized lignin nanoparticles was found to be higher than that of carbon black; however, the electrical conductivity was significantly reduced. These results led to the authors concluding that carbonized lignin nanoparticles could potentially be used as an alternative to carbon black in all applications excluding those requiring an electrically conductive material.
Sulfonated polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SPSPB) was used as a polymer matrix to create polymeric nanocomposites using graphite (G) and graphite-polyoxometalate (G-POM) as fillers. It was found that the nanocomposites had higher thermal and electrical conductivities than SPSPB alone, and that both the thermal and the electrical conductivity increased with increasing filler concentration. At all filler contents tested, the SPSPB/G-POM had both a higher thermal conductivity and a higher electrical conductivity than SPSPB/G. Increasing tensile strength was observed for the SPSPB/G-POM nanocomposite with increasing filler content which indicated that the nanoparticles significantly reinforced the polymer matrix.
