Synthesis and performance evaluation of paraffin microcapsules with calcium carbonate shell modulated by different anionic surfactants for thermal energy storage

Abstract

A series of phase change materials (PCMs) microcapsules based on industrial paraffin core and calcium carbonate (CaCO3) shell were successfully synthesized for thermal energy storage. The SEM results revealed that the composites are mainly of spherical morphology. The FT-IR and XRD confirmed that the composites were mainly composed of the vaterite CaCO3, paraffin, and a small amount of calcite CaCO3. Compared with the composites prepared with sodium dodecyl sulfonate (SDS) as anionic surfactant, DSC and TG results of composites prepared with sodium dodecyl benzene sulfonate (SDBS) demonstrated that the encapsulation efficiency increased but the thermal stability decreased. Besides, with the different concentrations of CaCl2, the influence of anionic surfactants on the performance of microcapsules had been discussed. The results exhibited higher encapsulation efficiency of microcapsules with SDBS than that with SDS, even up to ten times. When the mass of CaCl2 is about 0.05 mol, encapsulation efficiency with SDBS can reach up to 20.80%. Accordingly, the super-cooling of PCM was significantly suppressed. From all results, it is worth developing the PCMs microcapsules with CaCO3 shell modulated by different anionic surfactants for thermal energy storage and SDBS is more suitable for preparing PCM@CaCO3 microcapsules.