Evaluation of bio-derived structural blocks for segmented polyurethane phase change materials in thermal energy storage applications

The growing demand for sustainable energy solutions, driven by increasing electricity costs and greenhouse gas emissions, has intensified interest in new thermal energy storage systems. Phase change materials are promising candidates, yet most existing studies rely on petrochemical sources, with limited exploration of bio-based alternatives. This research focuses on developing polyurethane-based PCMs synthesized via the prepolymer method using petrochemical and bio-based poly(ethylene glycol) with different chain extenders. X-ray diffraction analysis showed that bio-based poly(ethylene glycol) possesses a distinct crystalline structure, exhibiting additional diffraction peaks at 13.50°-14.50° and 39.84°. The bio-derived polyurethane-based phase change materials achieved a latent heat of fusion of 51.4 J/g and a melting temperature of approximately 38°C, values comparable to petrochemical analogues. Furthermore, the materials exhibited high thermal reliability and stability over repeated heating–cooling cycles. Interestingly, repeated cycling promoted molecular rearrangement into a more ordered structure, resulting in up to a 46% increase in melting and crystallization enthalpies. Overall, the study demonstrates that substituting petrochemical poly(ethylene glycol) with bio-based derivatives can yield efficient, stable, and environmentally friendly polyurethane storage, aligning with the principles of green chemistry and the circular economy.