Synthesis and characterization of cellulose nanofibers improved melamine formaldehyde resin shell microcapsules for phase change thermal storage materials

Abstract A phase change microcapsule with n‐octadecane as the phase change core material and melamine formaldehyde resin as the wall material was successfully prepared by in situ polymerization using cellulose nanofibrillar filaments (CNF) as the emulsion stabilizer. The microencapsulation of phase change materials was characterized using scanning electron microscope, Fourier transform infrared spectroscopy x‐ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. The microcapsules had a perfectly spherical morphology with a core‐shell microstructure. The findings revealed that the microcapsules up to the highest efficiency of encapsulation and energy storage of 59.1% and 58.5%, respectively, were achieved when the CNF addition was 0.2 wt%, the core‐to‐wall mass ratio was 3:3.69, and the stirring rate was 1000 r/min. This work uses CNF as an emulsion stabilizer instead of conventional emulsifiers, which reduces the burden on the environment and provides a sustainable method for thermal energy storage and conversion.