Ionolysis of flexible polyurethane waste using ionic liquids for efficient and sustainable polyol recovery

Chemical recycling of polyurethane waste is essential for advancing circular economy objectives, as current technologies struggle to efficiently recover monomeric building blocks. Here, we present an efficient ionolysis-based recycling approach using 1-ethyl-3-methylimidazolium bromide (EMIM-Br) as bifunctional solvent-catalyst. Under mild conditions (150°C, 1 MPa), the ionic liquid disrupts hydrogen bonding and selectively cleaves urethane linkages, yielding virgin-like polyols. Polyols are efficiently separated from the reaction mixture, and the ionic liquid is readily recycled. EMIM-Br achieved a 94% depolymerization yield and 73% polyol recovery. Physicochemical analysis confirmed that the recovered polyols closely match commercial standards. Notably, incorporation of 25% recycled polyol into new formulations produced flexible PU foams with viscoelastic properties comparable to those of the reference material. This work offers a sustainable and scalable strategy for polyurethane foam recycling, addressing key limitations in current technologies and supporting resource-efficient materials development.