Prospects of high-value recycling methods for polyurethane based on the selective cleavage of C–O/C–N bonds

Abstract

Polyurethane (PU) is a multifunctional material widely used in diverse fields owing to its structural diversity and tunability. However, its widespread use has led to environmental pollution and energy-related challenges. Interestingly, with the continuous research attention given to the eco-friendly degradation of polymers, some degradation methods have emerged, such as biological recycling and construction of covalent adaptive networks. Current polyurethane recycling and utilization methods exhibit limitations, with landfill and incineration remaining the dominant disposal approaches. Among them, chemical recycling is the most promising method owing to its high efficiency and controllability, but the process of polyurethane chemical degradation is usually non-selective, and its selective degradation mechanism is still not clear. Thus, this review aims to elucidate the prospects of the selective chemical degradation of polyurethane and high-value recycling strategies based on the selective cleavage of C–O/C–N bonds. In addition, we discuss the selective chemical degradation of other carbonyl-containing polymers to offer some ideas and prospects for the strategy of selective degradation.