Phase change materials based on polyethylene glycol supported by graphene-based mesoporous silica sheets

Abstract

In order to solve the problems of leakage and low conductivity of polyethylene glycol (PEG) as a phase change material (PCM), meanwhile without phase separation during the process of use, graphene-based mesoporous silica sheets (GS) was prepared as a novel mesoporous material, then the PEG was absorbed into the mesopores of GS as a new phase change material composites (PCMs). The surface area and porosimetry analyzer (SAPA), Fourier transform infrared spectrometer (FTIR), Raman analysis, X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), Thermogravimetry analysis (TGA), Differential scanning calorimetry (DSC) were used to evaluate the properties of GS and phase change material composites (PCMs). The results indicated that GS was successfully synthesized, and the specific surface area and volume of GS were 669.829 m2/g and 5.889 × 10−1 cm3/g, respectively; PEG could be absorbed into the mesopores of GS, and the max mass fraction of PEG in PCMs was 80 wt%, and the enthalpy was up to 136.30 J/g; The phase change temperatures of PCMs were a little higher than that of pure PEG, and enthalpies of PCMs were slightly lower than the theoretical ones calculated by multiplying the mass percentage of PEG, which showed that the molecular heat movement of PEG was confined by GS.