Poly(ethylene glycol)-based polyurethanes based on dynamic oxime-urethane bonds for sustainable thermal energy storage

Traditional poly(ethylene glycol)-based polyurethane phase change materials (PUPCMs) are difficult to reprocess and non-recyclable because of their permanently cross-linking structure, leading to issues of resource waste. To overcome this problem, this study introduces dynamic bonds in PUPCMs to develop dynamic cross-linking networks. A series of polyurethane phase change materials containing dynamic oxime-urethane bonds (DOU-PUPCMs) are prepared using poly(ethylene glycol) (PEG), dimethylglyoxime (DMG) and hexamethylene diisocyanate (HDI) as raw materials. It has been shown that the obtained DOU-PUPCMs exhibit good heat storage capability and outstanding thermal stability. Importantly, the introduction of oxime-urethane groups provided DOU-PUPCMs with processibility. After multiple reprocessing cycles, the chemical structure and energy storage capacity of the DOU-PUPCMs essentially remain consistent with the original samples. The breaking and restructuring of oxime-urethane bonds and hydrogen bonds in DOU-PUPCMs makes them recyclable. This is not only significant for the development of recyclable and sustainable energy storage materials , but also complements studies such as the application of oxime-urethane bonds to PCMs.