Nanoencapsulation of oleic acid phase change material with Ag2O nanoparticles-based urea formaldehyde shell for building thermal energy storage

Abstract

Nanoencapsulated phase change material (NEPCM) was prepared with oleic acid as phase change material by its encapsulation into Ag2O nanoparticles (NPs)-based urea formaldehyde (UF) resin. NEPCMs were synthesized by in situ polymerization with different surfactants, to obtain a better shell material in terms of energy release, leak arrest and enhanced thermal properties. The morphology and particle size of the prepared NEPCM were analyzed by digital microscope and scanning electron microscope. Fourier transform infrared spectroscopy was used to determine the chemical structure. X-ray diffraction studies were carried out to ensure the presence of Ag2O NPs containing UF resin as shell material and its cubic crystal system. Thermo-physical properties were evaluated using differential scanning calorimetry (DSC), thermogravimetric analysis and thermal diffusivity analysis. DSC results revealed that the cationic surfactant-assisted synthesis of shell material has a comparatively good encapsulation ratio of 45.52%, and to further enhance the encapsulating capacity, Ag2O NPs was introduced. Addition of Ag2O NPs into the shell material shows improved encapsulation ratio of 54.82% with latent heat of 71.7 J g−1 for melting at 5.21 °C and hence better surface morphology, good thermal stability, better thermal conductivity and more suitability toward thermal energy storage in buildings.