Fabrication and characterization of microencapsulated n-heptadecane with graphene/starch composite shell for thermal energy storage

摘要

Microencapsulated n-heptadecane phase change material with self-assembled graphene/starch composite shells were prepared through a facile method. The compositions of the microcapsules were chemically evaluated by Fourier transform infrared spectroscopy. The results of Raman spectroscopy, optical microscopy images and scanning electron microscopy observations revealed the presence of the graphene nanoplatelets in the micro capsule shells. The step by step mechanism of the microencapsulation was explained, based on the obtained results. The thermogravimetric analysis results showed that graphene increased the microcapsule thermal stabilities. The graphene contents also facilitated the heat transfer of the microcapsules and improved the temperature control performance by 54% in the presence of 11.35 wt.% of graphene. Phase change properties and thermal reliability of the microcapsules were investigated by differential scanning calorimetry. The micro capsules had remarkable encapsulation ratios, encapsulation efficiencies and long-time operation reliability to use for thermal energy storage applications such as surface coatings for buildings.