Effect of graphene on the thermophysical properties of melamine-urea-formaldehyde/N-hexadecane microcapsules

Heat transfer performance remains a key factor for the potential application of microencapsulated phase change materials (microPCMs). The purpose of this work is to explore the effect of different amounts of graphene added on the thermophysical properties of microPCMs. Microcapsules containing n-hexadecane (C16) with a melamine-urea-formaldehyde (MUF) shell were synthesized by emulsion polymerization. The spectra of Fourier transform infrared spectroscopy (FTIR) confirmed that the MUF shell is fabricated on the surface of C16. Graphene is successfully mixed with microPCMs and the crystal type of microPCMs is not changed, which is detected by X-ray Diffraction (XRD). The results indicated that heat enthalpy of microPCMs gradually decreases with the rising addition of graphene, but the heat transfer performance and thermal stabilities are enhanced. In addition, graphene in microPCMs obviously reduces the degree of supercooling of C16. MicroPCMs with 0.05 wt% added graphene have the best anti-osmosis performance.