Preparation and structure-properties of crosslinking organic montmorillonite/polyurethane as solid-solid phase change materials for thermal energy storage

In order to solve the leakage problem of commonly used polyethylene glycol (PEG) phase change material (PCM), PEG reacted with 4′ 4-diphenylmethane diisocyanate (MDI) to prepare the polyurethane-based solid-solid phase change material (PU-SSPCM) by the two-step solvent method, and the influence of organic montmorillonite (OMMT) on the phase transition property and crystallization capacity of PU-SSPCM was first studied. The solid-solid phase change polyurethane materials were successfully prepared when the molar ratio of PEG to MDI was 0.75, and the organic montmorillonite acted as a crosslinking heterogeneous nucleating agent to improve the temperature control capacity, the crystallization ability and the thermal stability of the solid-solid phase change polyurethane material. When the addition of OMMT was 0.5 wt%, the phase change enthalpy of PU-SSPCM increased to 106.8J/g from 95.46J/g, a constant temperature platform appeared for about 300 s during both the heating and cooling process, thus demonstrating excellent temperature control ability. The relative crystallinity increased to 74.8% from 66.5% and the initial thermal weight loss temperature was increased from 348 °C to 368 °C.