Hyperbranched polyurethane as novel solid–solid phase change material for thermal energy storage

A series of novel hyperbranched polyurethane copolymer (HB-PUPCM) using hyperbranched polyester as chain extender was prepared via a two-step process. The phase transition behaviors and morphology of the HB-PUPCM films were investigated using differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMA), thermo-gravimetric analysis (TGA), wide-angle X-ray diffraction (WAXD), polarizing optical microscopy (POM) and tapping-mode atomic force microscopy (AFM). HB-PUPCM was proven to a good polymeric solid–solid phase change heat storage material.