Highly efficient depolymerization of waste polyethylene terephthalate for upcycling in colorful pigments and coatings

Abstract

Developing a highly efficient and one-pot strategy for upcycling post-consumer waste polyethylene terephthalate (PET) into feedstock for the production of valuable products at scale remains a formidable challenge through chemical recyclability. Here we present the chemical degradation of waste PET sheets at scale via a one-pot process, which yields active hydroxyl-terminated oligomers with a recycling efficiency of 98.4 wt%. By utilizing the degradation products as substrates, we have prepared robust and vibrant organic pigments with a highest reflection efficiency of 89.6%. Furthermore, these degradation products serve as a substantial foundation for waterborne polyurethane. The combination of these two renewable and valuable materials enables the creation of multi-colored coatings boasting remarkable brightness and significant coloring strength. In essence, this work establishes a simple upcycling strategy for waste PET and the micro- and nanoplastics into valuable and environment-friendly chemical products at scale with high efficiency.