Synthesis and Performance of Thermoplastic Polyurethane-Based Solid–Solid Phase-Change Materials for Energy Storage

This study focuses on the design and synthesis of a novel tetrahydroxy compound, namely terephthalic acid bis-(2-hydroxy-1-hydroxymethyl-ethyl) ester (TABE), to prepare polyurethane-based phase-change materials with a higher phase-change enthalpy and suitable phase-change temperature. Based on the unique molecular structure of TABE, a series of thermoplastic polyurethane-based solid-solid phase-change materials for energy storage were synthesized via a three-step condensation reaction of polyethylene glycols with TABE, 4,4'-diphenylmethane diisocyanate (MDI), and polyethylene glycol monomethylether (MPEG). The composition and properties of the as-synthesized samples were characterized using several experimental techniques. The results showed that the polyurethane-based solid-solid phase-change materials presented in this work have a higher phase-change enthalpy; the maximum phase-change enthalpy values associated with the heating and cooling cycles were 153.51 J/g and 143.91 J/g, respectively. In addition, they showed excellent thermal reliability and stability, i.e., the initial decomposition temperature and the maximum decomposition temperature were measured to be 320.16 degrees C and 451.12 degrees C, respectively. Most importantly, the best phase-change temperatures of the phase-change materials ranged between 22.41 and 48.41 degrees C, and the phase-change materials can be directly melted and processed. Owing to these properties, these materials can be applied in textile products, telecommunication and microprocessor equipment, and constructions.