Closing the Polyurethane Loop: Repolyols from Chemically Recycled Bio-Modified Foams for Viscoelastic Applications.

This article develops new-generation viscoelastic polyurethane foams (VPUFs) obtained using repolyols derived from chemically recycled flexible foams and bio-based polyurethane foams, in accordance with the Circular Economy framework. The repolyols were produced by chemolysis using a low-molecular-weight glycolyzing agent. The repolyols were used as a partial substitute for conventional petrochemical polyols in VPUF formulations. The physicochemical properties of the repolyols, including hydroxyl value (HV), amine value (AmV), and viscosity, were characterized. The effect of the repolyols on the foaming reaction and the cellular structure of the resulting foams was assessed. The resulting VPUFs were tested for apparent density, hardness, hysteresis, resilience, recovery time, and comfort factor. Replacing up to 15% by weight of conventional petrochemical polyols with repolyols results in VPUF with 36% higher apparent density, 32% higher hardness and 27% higher hysteresis than REF. The developed polyurethane foams are in line with the principles of sustainable development and the Circular Economy.