Preparation and Characteristics of Microencapsulated Lauric Acid as Composite Thermal Energy Storage Materials

Abstract

A novel microencapsulated phase change material was prepared by sol-gel method using lauric acid (LA) as core material and titanium dioxide (TiO₂) as shell material. The composites were characterized by field emission scanning electron microscope (FE-SEM), Fourier transformation infrared spectrometer (FT-IR), differential scanning calorimeter (DSC) and thermogravimetric analyzer (TGA). The results of the FE-SEM and FT-IR indicated that LA was well coated in the shell of TiO₂ and no chemical reaction occurred between them. The results of the DSC denoted that the composites with 43.5 % encapsulation ratio of the LA melted at 44.39 ℃ with the melting enthalpy of 67.54 J/g and solidified at 43.64 ℃ with the solidification enthalpy of 65.17 J/g. The results of the TGA signified that the thermal stability and fire resistance of the microcapsules were greatly enhanced under the protection barrier of TiO₂. The thermal decomposition of the microencapsulated LA with TiO₂ shell hardly occurred under 200 ℃. That is to say, the composites possess good thermal stability in the operating temperature range. In conclusion, the prepared microencapsulated composites can be incorporated into solar energy storage like solar air heaters and into electronic devices as heat sinks.