Preparation and characterization of pentaerythritol/butane tetracarboxylic acid/polyethylene glycol crosslinking copolymers as solid-solid phase change materials

Pentaerythritol/butane tetracarboxylic acid/polyethylene glycol (PBPEG) crosslinking copolymers as a novel solid-solid phase change material (SSPCM) were successfully synthesized through the reaction mechanism and conditions of hydroxyl-carboxyl condensation reaction. The composition and chemical structure, crystalline properties, phase change behaviors, thermal reliability and chemical stability of PBPEG crosslinking copolymers were investigated by Fourier transform infrared spectroscopy (FT-IR), wide-angle X-ray diffraction (WAXD), polarization optical microscopy (POM), differential scanning calorimetry (DSC), and thermogravimetry (TGA), respectively. The results show that PBPEG crosslinking copolymers have typical solid-solid phase transition temperatures in the range of 10.31 approximate to 53.27 degrees C and high latent heat enthalpy in the range of 89.6 approximate to 102.8J/g, the synthesized SSPCMs have good thermal reliability and chemical stability after 300 thermal cycles, and PBPEG crosslinking copolymers have good thermal stability before 364 degrees C. In summary, the synthesized PBPEG crosslinking copolymers could be potentially used for thermal energy storage.