Thermal and Mechanical Characterization of Microencapsulated Phase Change Material in Cementitious Composites

This study evaluated the thermal and mechanical characterization of microencapsulated phase change material blended cement tiles. The study utilized a eutectic mixture of capric acid (CA), and stearic acid (SA) synthesized using the melt blending method as an additive to save energy in building structures. Microencapsulation of the eutectic mixture was done by the sol–gel technique using silica as a shell material to avoid leakage issues. Stirring the solution consisting of silica precursor and eutectic mixture facilitated the formation of CA–SA loaded core and silica as shell material. The developed microcapsules exhibited good thermal stability, with thermal conductivity of 1.79 and 1.47 at 2.5% and 5.0% eutectic mixtures, respectively. Using encapsulated phase change material into the cement composite causes reduction indoor air temperature and causes achievement of comfort temperature by consuming less energy. FTIR (Fourier transform infrared spectroscopy) spectra of the microcapsules confirmed the characteristic vibrational frequencies for capric acid, stearic acid, and the silica particles. SEM (scanning electron microscope) described the morphology of the microcapsules as having a spherical shape. The differential scanning calorimetry (DSC) test results indicated that the microencapsulated phase change material (MPCM) melted at 22 °C, and the thermal stability was confirmed from thermogravimetric analysis (TGA). Adding MPCM into the cement mortar resulted in a slight drop in compressive strength of the mixtures. However, the indoor comfort was enhanced by reducing the temperature owing to the absorption of heat energy by the phase changing the property of the eutectic components. Overall, the MPCM exhibited good thermal stability and could be suitable for thermal energy storage in building applications.