Microwave Assisted Preparation of Poly(ethylene) glycol/Lignin Blends for Thermal Energy Storage

In this research, lignin, an abundant bioresource and a natural polymer, is investigated for its use as the supporting material while poly(ethylene glycol) (PEG) has been used as the working element. Various ratios of PEG and lignin were studied and the shape-stabilized phase change material (SSPCM) was prepared using microwave assisted blending, which proves to be one of the efficient and green ways of preparing the blends. The chemical structure of the PCM blend was confirmed using FTIR spectroscopy. The thermal and crystalline properties were investigated using differential scanning calorimetry, thermogravimetric analysis and X-ray diffraction. The morphology was studied with field-emission scanning electron microscopy (FESEM), energy dispersive X ray spectroscopy (EDAX) and polarized optical microscopy (POM) suggesting a homogeneous network formation of the composite. Maximum loading of PEG was found to be 70%, giving enthalpy of 100.91 J/g. The prepared PCM exhibited excellent thermal reliability even after 100 thermal cycles. This novel PCM blend of PEG and lignin is considered as a promising candidate in terms of reliability and renewability making it suitable for various thermal energy storage applications.