Preparation and characterizations of hydroxyapatite microcapsule phase change materials for potential building materials

Abstract This paper aims to develop a novel thermal storage cement-based material (TSCM) with good service performances using rigid phase-change microcapsules. Microcapsules were made of hollow HAP incorporated with capric acid (CA). The fabricated composite phase change material (CA/HAP) was characterized by using various techniques, such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier Transform infrared spectroscopy (FTIR), thermogravimetry (TGA) and differential scanning calorimeter (DSC). The basic properties of TSCM mortars with varying amount of CA/HAP including workability, hydration heat, compressive strength and thermal regulating ability were also assessed. The test results showed that CA/HAP is small and regular in spherical shape and exhibits high absorption ratio and good physicochemical stability. The incorporation of CA/HAP in cement-based materials leads to a decrease of workability, acceleration of hydration process and significant improvement of thermal regulation property. The compressive strength of mixtures containing CA/HAP is noted to be increased when incorporating 10% of CA/HAP by volume.