Bio-Based UV-Curable Resins Derived from Waste PET Glycolysis Products for LCD 3D Printing

Abstract To facilitate the high-value upcycling of waste polyethylene terephthalate (PET) and the advancement of sustainable materials, a comprehensive strategy encompassing chemical recycling, functionalization, and upcycling was proposed. Initially, bis(2-hydroxyethyl) terephthalate (BHET) was derived via the glycolysis of waste PET with ethylene glycol, which subsequently served as a precursor for the synthesis of a series of bio-based polyester polyols (BPOs). These polyols, characterized by controllable branched structures, were synthesized through melt polycondensation of BHET and the bio-based platform molecule, citric acid (CA). Bio-based UV-curable resins (BUVRs) were fabricated by incorporating the BPOs into a polyurethane acrylate matrix, and the introduction of BPO significantly improved both the photocuring behavior and mechanical properties of the resulting materials. Specifically, the double-bond conversion of the resin containing 5 wt % BPO1 increased to 91.3%, representing a substantial improvement over the BPO-free control. Mechanical characterization further revealed that the tensile strength of the BUVR was nearly doubled, rising from 19.7 to 37.9 MPa with increasing BPO1 content. Furthermore, owing to their exceptional resistance to nonpolar solvents, the BUVRs were successfully utilized in LCD 3D printing to yield components characterized by high dimensional stability and precision. Consequently, this study establishes a low-carbon and efficient paradigm for the upcycling of waste PET and the fabrication of high-performance bio-based UV-curable resins.