Improvement of the thermal conductivity of a phase change material by the functionalized carbon nanotubes

Multiwalled carbon nanotubes (MWNTs) were functionalized by oxidation and adsorption of pyrogallol and used to prepare the palmitic acid (PA)/MWNT composite. Spectra of XPS and FTIR were used to characterize the functionalized MWNTs. UV–vis spectra showed the dispersibility of MWNTs in the PA/ethanol solution. Thermal conductivity and DSC measurements showed an enhancement of the thermal conductivity of PA and an improved heat transfer of PA, respectively, by the functionalized MWNTs. This work reveals the relationship between the distribution of MWNT in the PA matrix and the thermal conductivity of the composite. The MWNTs with more oxygen-containing groups can have more hydrogen bonding interactions with the PA molecules, and the nanotubes are better dispersed in the PA/ethanol solution. As a result, MWNTs can be well-dispersed in the PA matrix, and the thermal conductivity of the composite is significantly enhanced.

► f-MWNTs have hydrogen bonding interactions with the palmitic acid (PA) molecules.
► A good distribution of f-MWNTs in the PA matrix can be achieved.
► The thermal conductivity of palmitic acid is significantly enhanced.