Synthesis and Performances of Phase Change Materials Microcapsules with a Polymer/BN/TiO2 Hybrid Shell for Thermal Energy Storage

Paraffin was encapsulated in a poly(methyl methacrylate) (PMMA)/BN/TiO2 hybrid shell to obtain a novel phase change material (PCM) microcapsule for latent-heat storage. Scanning electron microscope micrographs showed that the resultant composite PCMs exhibited a nearly spherical morphology with a size of 10-20 mu m and BN/TiO2 nanoparticles were tightly embedded on the microcapsule surface. The results of thermogravimetric analysis and thermal conductivity test demonstrated that the PMMA/BN/TiO2 composite shell gave the microencapsulated paraffin an excellent thermal performance. Compared to pure paraffin, the thermal conductivity of microcapsules could significantly be enhanced by 117.0%, and the maximum decomposing temperature has an increase of 25.4 degrees C. The analysis of differential scanning calorimetry and thermal reliability test indicated that the composite PCMs also presented good heat storage capacity and high thermal reliability for latent-heat storage and release. After a heating-cooling cycle test was repeated 100 times, the composite microcapsule still showed a similar phase change performance as before, which can be attributed to the protective effect of PMMA/BN/TiO2 hybrid shell. With increased demands for economical and high-performance renewed energy storage materials, the prepared composite PCMs show great potential applications in thermal energy storage.