Advances in Polyester Waste Recycling Technology: Focused on the PET System and Prospects for PETG Challenges

Polyethylene terephthalate (PET) recycling technology has developed into a mature system, providing a key paradigm for the circular utilization of polyester waste. Its pathways are primarily divided into mechanical recycling and chemical recycling. Mechanical recycling converts waste PET into rPET through physical processes such as efficient sorting, deep cleaning, and melt extrusion. However, the resulting product often faces issues of decreased intrinsic viscosity and thermal oxidative degradation. Chemical recycling, particularly depolymerization techniques like saccharification, hydrolysis, and methanolysis, can reduce PET waste back to monomers. After purification, these monomers can be repolymerized into virgin-quality PET, achieving a closed-loop cycle. However, this approach faces challenges related to cost and process complexity. Against this backdrop, this paper further explores potential recycling methods for polyethylene terephthalate-1,4-cyclohexanedimethyleneterephthalate (PETG). This paper argues that the experience of PET recycling provides a crucial foundation for addressing PETG challenges but is not a direct solution. Future development directions include: developing intelligent sorting technologies, creating highly efficient selective catalysts to optimize depolymerization reactions, and other initiatives. These measures are essential for establishing an efficient recycling system for complex polyester waste.