Improved thermal properties of paraffin wax by the addition of TiO2 nanoparticles

Abstract TiO 2 nanoparticles about 20 nm in diameter in the form of anatase were prepared and characterized. The nanoparticles were successfully dispersed into a paraffin wax (PW) matrix without any surfactant. The differential scanning calorimetric instrument and the transient short hot-wire method were used to measure the thermal properties of the TiO 2 /PW composites. It is found that the phase-change temperature and latent heat capacity vary with TiO 2 nanoparticles loading levels. When the loading is not over 1 wt%, the phase-change temperature drops, and the latent heat capacity increases. When the loading is over 2 wt%, the phase-change temperature increases, and the latent heat capacity drops. A significant increase in latent heat capacity is found around 0.7 wt% loading. The thermal conductivity of the composites increases monotonically with increasing TiO 2 loading. But such a tendency tends to decrease when the loading is over 3 wt%.