Facile Strategy in Designing Epoxy/Paraffin Multiple Phase Change Materials for Thermal Energy Storage Applications

Designing novel phase change materials (PCMs) is of vital importance in achieving the sustainable development of energy. Here, we facilely prepare a series of novel multiple solid solid PCMs (SSPCMs, EPPa-X systems) by blending paraffin, epoxy resin with crystalline side chains (D18), and poly(propylene oxide)diamine together followed by a one-pot curing process. Strong intermolecular forces between paraffin and D18 (based on their good compatibility) and a reliable three-dimensional (3-D) cross-linking network of epoxy resin form a unique encapsulation mechanism, which provides the EPPa-X SSPCMs with excellent shape-stable properties and superior thermal stability (remain stable below 180 degrees C) without sacrificing too much latent heat of paraffin (only 1.6% latent heat loss). Due to the combination of two melting processes at 36 and 60 degrees C derived from D18 and paraffin, respectively, the latent heat of the EPPa-50 system is high, up to 152.6 J/g. Besides, the supercooling extent of D18 decreased from 13.6 to 10.5 degrees C with the addition of paraffin due to the heterogeneous nucleation effect. The novel EPPa-X SSPCMs possess tremendous potential for a wide range of applications due to their facile preparation, low cost, high reliability, and excellent phase change properties, while the unique encapsulation mechanism may open a new door for preparing other novel types of PCMs.