Performance of cementitious composites with nano PCMs and cellulose nano fibers

Abstract

Nanotechnology is a promising technology that leads to very effective and efficient innovations in different disciplines. As it deals with substances on a nanoscale, it gives the opportunity to modify materials and obtain desired properties. In this study Phase Change Material (PCM) nano capsules are used to enhance the thermal properties of cellulose nano fiber (CNF). PCM/CNF nano composite insulator is developed and incorporated within cement mortar to enhance thermal properties of cement mortar. CNF is extracted from wheat straw by a chemo-mechanical method in the first part. The second part includes synthesis of PCM nano capsules using mini emulsion in situ polymerization method, and then PCM/CNF nano composite is prepared by encapsulated CNF within PCM nano capsules. The morphology, chemical, and thermal properties of CNF, nano capsules, and PCM/CNF nano composite are determined. Modified cement mortar is prepared by mixing different percentages of CNF, PCM nano capsules, and PCM/CNF nano composite with cement mortar. The thermal and mechanical properties of modified cement mortar are examined; the increase of thermal conductivity of cement mortar incorporated PCM/CNF nano composite is reduced in comparison with the addition of CNF alone. Regarding the compressive strength of cement mortar, the addition of CNF and PCM/CNF nano composite leads to increase compressive strength of cement mortar, where the greatest result is achieved with the addition of 0.5 wt%.