Preparation and Thermal Properties of Microencapsulated Polyurethane and Double-Component Poly(ethylene glycol) as Phase Change Material for Thermal Energy Storage by Interfacial Polymerization

Phase change materials (PCMs) with high thermal storage densities and nearly isothermal process can use latent heat to store energy. However, their suboptimal leaching resistance and narrow temperature range hindered their development. In this work, an ingenious design of microencapsulated PCMs with core–shell structure (M-PCMs) was built by interfacial polymerization. Formaldehyde-free polyurethane was selected as the shell. Compounding poly(ethylene glycol) formed a double-component energy storage mode and acted as core. The morphology, leaching resistance, chemical structure, and thermal properties of M-PCMs were investigated. Results showed the M-PCMs were constructed with an even size distribution by the synergism of core/shell mass ratio optimization and emulsifier emulsification. The −N═C═O on isophorone diisocyanate reacting to diethylene triamine with −NH2 group formed a polyurethane shell through urea linkage and polymerized compounding PEG by −OH. The M-PCMs obtained high latent heats of 97.19 and 98.58 J·g–1 which were regulated by two peak temperatures at 28.02 and 36.24 °C as well as 23.12 and 32.88 °C during the energy storage/release stage, respectively. The undercooling was reduced by the energy compensation of temperature levels. This research offered a novel way for ecoenvironment M-PCMs fabrication, and the obtained M-PCMs are promising for energy storage temperature extension and indoor comfort improvement.