Upcycling of Commodity Thermoset Polyurethane Towards Smart Materials with End-User-On-Demand Programmable Properties...

Polyurethane is indispensable to our life, but its end-of-life wastes bring severe environmental problems due to the bulky volume and thermoset nature. The regenerated products based on current recycling strategies normally have fixed mechanical properties, limiting adaptability to diverse applications. Here, we present a chemical recycling strategy that can transform polyurethane waste into smart materials with end-user-on-demand programmable properties and adaptable applications. It is achieved through inserting a thermal-triggered network topology transformation switch in the polyurethane. The network topology transformation switch endows the regenerated materials with on-demand mechanical programmability, which could achieve a 54-fold modulus enhancement from 5 MPa (soft rubber) to 270 MPa (rigid/semi-rigid plastic). More importantly, the thermal-triggered feature empowers end-users not only to tailor material stiffness post-production, but also to benefit from enhanced portability, functional adaptability for multi-scenario applications. Our strategy of recycling waste into products with programmable properties and adaptable applications is not only environmentally friendly but also highly appealing to the end-users, providing a promising direction in the future reuse of plastic waste.