Chemical upcycling of commodity thermoset polyurethane foams towards high-performance 3D photo-printing resins.

Polyurethane thermosets are indispensable to modern life, but their widespread use has become an increasingly pressing environmental burden. Current recycling approaches are economically unattractive and/or lead to recycled products of inferior properties, making their large-scale implementation unviable. Here we report a highly efficient chemical strategy for upcycling thermoset polyurethane foams that yields products of much higher economic values than the original material. Starting from a commodity foam, we show that the polyurethane network is chemically fragmented into a dissolvable mixture under mild conditions. We demonstrate that three-dimensional photo-printable resins with tunable material mechanical properties-which are superior to commercial high-performance counterparts-can be formulated with the addition of various network reforming additives. Our direct upcycling of commodity foams is economically attractive and can be implemented with ease, and the principle can be expanded to other commodity thermosets.