Synthesis of phase change microcapsules with binary fatty acid ester core and their feasibility investigation in energy conservation of cementitious materials

In this study, novel microencapsulated phase change materials (PU-UF MPCMs) with methyl palmitate and methyl stearate as core and double-layered shell structure were designed for building energy conservations. Their composition, microstructure and thermal performances were determined by techniques including optical microscope (OM), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Effects of PU-UF MPCMs on the thermal performance of cementitious composites were also investigated. Results show that PU-UF MPCMs with spherical shape and double-layered shell structure were successfully prepared. DSC results show that the latent heat of PU-UF MPCMs is 137.6 J/g and the melt temperature of cores in PU-UF MPCMs is 24.2 °C. 5%-15% PU-UF MPCMs addition increases the thermal storage capacity of cement pastes through a phase transition process, among which 15% PU-UF MPCMs leads to the highest thermal storage capacity. Those results suggest that PU-UF MPCMs exhibit the potential for enhancing energy savings and thermal comfort of buildings.