(403m) Chemical Upcycling of Polyurethane Waste Via ‘Imidazolysis’: Toward Circular Plastic Valorization

As the magnitude of polymeric waste accumulating in our environment has become increasingly clear, the global urgency for a sustainable solution is a primary need. Among various strategies, the chemical modification of post-consumer synthetic polymers offers a promising route to transform inherent chemical potential of waste plastics into value-added materials. The availability of multifunctional alcohol and isocyanate monomers has led to the commercial growth of polyurethanes (PU) as mattresses, flexible or rigid foams, insulators, adhesives, etc. However, the recycling rate remains very negligible due to the high stability of the urethane linkages. In this work, we introduce a depolymerization technique for PU termed ‘imidazolysis,’ inspired by our previous success in upcycling PET plastics via imidazole-based compounds. Using small, bifunctional carbamates as model compounds, we observed selective cleavage of the urethane O atom by imidazoles, yielding imidazole carboxamides. Remarkably, commercial PU foam was effectively depolymerized into functional compounds, enabling the quantitative recovery of polyol.