Synthesis and thermal energy storage properties of a solid–solid phase change material with a novel comb-polyurethane block copolymer structure

Abstract

A novel phase change material (PCM), namely, comb polyurethane with polyethylene oxide segments as side chains (DMPEG–PU), was synthesized through the reaction between diethanolamine-modified monomethoxy polyethylene glycol (MPEG) with isophorone diisocyanate and 1,4-butanediol. The crystalline property, phase change property, and thermal stability were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TG), wide-angle X-ray diffraction (WAXD), scanning electronic microscopy (SEM), and polarization optical microscopy (POM). An accelerated thermal cycling test was then conducted to reveal the thermal reliability of the synthesized DMPEG–PU. The WAXD patterns and POM images showed that the synthesized DMPEG–PU possesses a completely crystalline structure and smaller spherulites compared with the pristine MPEG. The DSC results showed that DMPEG–PU (with 85% weight percentage of MPEG) is a typical solid–solid PCM with high thermal transition enthalpy of more than 120 J g⁻¹, which is higher than the thermal transition enthalpy of polyethylene glycol-based polyurethane. TG results showed that the synthesized DMPEG–PU exhibits satisfactory thermal stability.