Development of nanomodified eco-friendly thermal energy storing cementitious composite using PCM microencapsulated in biosourced encapsulation shell

This study presents the development of a thermal energy storing cementitious composite that incorporates phase change material (PCM) microencapsulated in biosourced polymer shell (m-PCM). The biodegradability of the encapsulated PCM was assessed using Nuclear Magnetic Resonance (NMR), which confirmed the high biodegradability of the m-PCM shell under specific environmental conditions. To examine the thermophysical properties of the m-PCM, Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA) were performed. The DSC results revealed exothermic enthalpies of 84.7 J/g and 140.2 J/g, with associated peak temperatures of -3.2 °C and -22.9 °C, respectively. Subsequently, the m-PCM was incorporated into cement-based mortar at proportions of 5%, 10%, and 15% by weight of binder. Uniaxial compression tests were conducted to evaluate the effect of the m-PCM on the mechanical properties of the mortar. The results indicated a significant decrease in mechanical strength upon incorporating the m-PCM. However, this reduction in strength was mitigated by the addition of silica fume (SF) and multiwalled carbon nanotubes (MWCNTs) in combination. Furthermore, a thermal cycling test was performed to examine the behavior of the nanomodified m-PCM incorporated mortar under varying ambient conditions. The results showed that the addition of MWCNTs improved both the mechanical performance and thermal performance of the composite.