Construction of MXene-enhanced rigid polyurethane foam/polyethylene glycol phase change composites for solar thermal conversion and storage

In this study, various rigid polyurethanes foams (PUFs) with different morphologies were prepared and subsequently used for encapsulating the phase change material, polyethylene glycol (PEG). To address the low photothermal conversion efficiency of polyurethane-based phase change materials, MXene was successfully synthesized via an in-situ hydrofluoric acid (HF) etching method and incorporated into the PEG to obtain MXene@PEG composite material. Finally, a series of innovative MXene@PEG-PUF phase change composites were successfully fabricated by utilizing PUFs as the supporting matrix and the MXene@PEG composite as the phase change component through a vacuum impregnation technique, and their thermophysical properties and photothermal conversion performance were systematically studied. The results show that PUF is the ideal capsulation material for PEG. And MXene@PEG-PUF demonstrates a high PCM loading rate (>80 wt%) and a high latent heat storage enthalpy (>140 J/g) with a relative enthalpy efficiency of 99.5%, maintaining excellent shape stability and relative enthalpy efficiency of 95.58% after 150 thermal cycles. This highlights its superior thermal reliability, making it suitable for practical building energy-saving applications. Most importantly, the incorporation of MXene into PUF@PEG significantly enhances solar-to-thermal conversion capability, attributed to the exceptional photothermal characteristics of MXene.