Fabrication and performances of microencapsulated palmitic acid with enhanced thermal properties

Abstract

This study focuses on the synthesis of microencapsulated phase change materials (MEPCMs), consisting of a palmitic acid (PA) core within an aluminum hydroxide oxide (Al2O3·xH2O) shell, using a sol-gel method. Aluminum isopropoxide (AIP) was used as a precursor for the aluminum hydroxide oxide shell. The MEPCMs were synthesized using four different weight ratios of PA/AIP. The effects of the PA/AIP weight ratio on the encapsulation characteristics and thermal properties of the MEPCMs have been investigated. The microcapsules were spherically shaped with an average diameter of 1.689-3.730 μm. Encapsulated PA confirmed the outstanding phase-change performance with specific heat and thermal stability enhancement. The final results suggested that the weight ratio of PA/AIP has an important effect on the morphology, encapsulation efficiency, and durability of the MEPCMs. A higher weight ratio of AIP/PA led to a smaller diameter size with enhanced thermal conductivity, thermal effusivity, and thermal stability of the MEPCMs. The thermal conductivity of PA microcapsules was considerably increased because of the fabrication of a thermally conductive aluminum hydroxide oxide shell. It can be concluded that the prepared MEPCMs employ an excellent energy storage potential because of their ideal latent heat, high thermal conductivity, and thermal stability. © 2015 American Chemical Society.