Linear polyurethane ionomers as solid–solid phase change materials for thermal energy storage

Linear polyurethane (PU) ionomers were synthesized as solid–solid phase changing materials (PCMs) for thermal energy storage . Poly(ethylene glycol)s (PEGs) with 6000 and 10,000   g/mol number average molecular weight were used as latent heat storage materials, and 4,4-diphenylmethane diisocyanate (MDI), N-methyldiethanolamine (MDEA) and 1,3-Propanesulfonate (PS) were used as supporting materials. The phase change enthalpies of PU ionomers were 142.5   J/g and 152.3   J/g respectively, which were much close to the highest reported value of the branched PUPCM or the cross-linking PUPCM. The results of Fourier transform infrared spectroscopy (FT-IR) and atomic force microscopy (AFM) suggested a high degree of phase separation existed in PU ionomers . And the thermal resistance of PU ionomers was improved by the introduction of ionic groups.