Integrated upcycling of waste PET and CO2 into UV-curable polyurethane acrylates via CO2-based polyols

초록

Growing concerns over climate change and plastic waste have intensified the demand for integrated strategies enabling carbon circularity. This study presents an integrated upcycling approach that converts waste polyethylene terephthalate (PET) and CO2 into functional polyols and subsequently into ultraviolet (UV)-curable polyurethane acrylate (PUA) films. Waste PET was depolymerized into bis(2-hydroxyethyl) terephthalate (BHET), which was employed as a renewable initiator for propylene oxide (PO)/CO2 copolymerization to produce PET-CO2 polyols with tunable molecular structures and compositions. The resulting polyols enabled the formation of UV-curable PUA films with controllable network structures and tunable thermomechanical properties, exhibiting glass transition temperatures ranging from −36.4 to 17.5 °C and tensile strengths up to 13.6 MPa. Increased incorporation of carbonate linkages and BHET-derived aromatic units promoted crosslink density, restricted chain mobility, and enhanced the thermal and mechanical performance of the UV-cured PUA films. Comparison with conventional polypropylene glycol (PPG)-based systems further demonstrated the structural advantages of PET-CO2 polyols in forming rigid and densely crosslinked polymer networks. These results establish a clear structure–network–property relationship governed by polyol composition and demonstrate a sustainable route for the integrated utilization of waste PET and CO2 to produce value-added UV-curable polyurethane materials.

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