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.