A new strategy for efficient chemical degradation and recycling of polyurethane materials: a multi-stage degradation method

An efficient strategy for the chemical degradation of polyurethane materials to recover polymerizable polyols has long been sought as a means of achieving green chemistry and circular resource utilization. However, this remains a major challenge. The present investigation endeavors to address this conundrum by delving into the intricacies of the multi-stage degradation (MSD) mechanism and successfully executing a gradient deconstruction of PUFs at low temperatures with minimal energy consumption. This approach involves a preliminary deconstruction of PUFs via ammonolysis, followed by deep depolymerization through acidolysis. The resulting recycled polyols (RPs) have high reactivity and can be used as a partial substitute for virgin polyol (up to 30 wt%) without purification treatment in the production of flexible PUFs. Furthermore, the MSD approach exhibits good adaptability and can be employed for the recycling of other types of PUFs, with the obtained RP being capable of up to 25 wt% VP substitution in the synthesis of new PUFs. Our research represents a significant advance in the development of efficient chemical degradation technologies for PUFs, which can support the transition to green chemistry and resource circularity. It provides valuable theoretical support for the industrialization of PUF degradation and upcycling.