Incorporation of Micro-encapsulated Phase Change Materials and Cellulose Nanofibers in Cement-Based Nanocomposites for Thermal Comfort of Buildings

PCM microcapsules envelopes have been successfully synthesized using anionic surfactant Sodium Dodecylbenzene Sulfonate (SDBS), where the lauric acid represents the core material and CaCO3 is the shell. With a high encapsulation rate, these microcapsules have demonstrated satisfactory phase change performance. It has been established that encapsulating lauric acid with CaCO3 in an emulsion can provide good thermal conductivity. This material has demonstrated good anti-osmosis characteristics in microcapsules by preventing internal lauric acid from evaporating and keeping it retained when the temperature rises. Cellulose nanofibers modified by grafting alkyl chains and by adsorbing PCM (lauric Acid) on the surface of the fibers reduced the amount of absorbed water. The samples were made using an anionic surfactant emulsion (SDBS) to disperse the nanofibers and reduce the size of the pores in the material. The influence of modified cellulose nanofibers on the physical properties of cement-based mortars, such as compressive strength and thermal conductivity has been investigated. The addition of 0.5 wt% of modified cellulose nanofibers resulted in a 90% increase in compressive strength. The presence of modified cellulose nanofibers has made a significant contribution to the properties of the mortar by improving the hydration of the cement by producing more calcium silicate gel and portlandite, as well as lowering its thermal conductivity in order to achieve building thermal comfort.