Enhanced Thermal Performance of Phase Change Material Microcapsules Using Halloysite Nanotubes

The organic phase change material (PCM) microcapsules have a great prospect in thermal energy storage and temperature control. But the disadvantages of poor thermal conductivity and ignitability restrict their application and development. So how to both improve thermal conductivity and flame retardancy at the same time has become an important issue. In this study, the PCM microcapsules with halloysite nanotubes (HNTs) are synthesized by the emulsion copolymerization method to enhance the thermal conductivity and flame retardant of microcapsules. FT-IR, XPS and SEM prove the microcapsules are synthesized successfully and HNTs are set in microcapsules. Moreover, DSC suggests melting peak temperatures and latent heat of microcapsules are 32.91 celcius and 110.65 J/g, respectively. Besides, the room model was introduced to evaluate the application potential, which shows that phase change material microcapsules with halloysite nanotubes possess great thermal storage efficiency and temperature regulation capability. The cone calorimeter measurement indicated that the peak of heat release rate and total heat release decrease 20.76% and 57.28%, respectively, after adding HNTs, which means phase change material microcapsules with halloysite nanotubes possess satisfactory flame retardant. Therefore, it is confirmed that the novel microcapsules have excellent thermal conductivity and flame retardant. Now most research is only concentrated on improving the thermal conductivity or flame retardant of organic phase change material microcapsules. This study simultaneously enhances the thermal conductivity and flame retardant of organic phase change material microcapsules by halloysite nanotubes.