Chemical recycling of multi-materials from glycol-modified poly (ethylene terephthalate)

Multi-materials, such as payment or access cards commonly in circulation, are non-recyclable. We show that the adoption of glycol-modified poly(ethylene terephthalate) (PET-G) as an alternative thermoplastic enables a transition from the current linear economy to a sustainable circular economy for these multi-materials. For the first time, we demonstrate the chemical recycling of PET-G. The system promotes effective depolymerization of both pure PET-G streams and PET-G multi-materials. Higher catalyst loading enables fast depolymerization kinetics and exceptional selectivity for mixed plastics under mild conditions, with up to 93% BHET conversion. Extending this process to multi-materials, less expensive and large-scale depolymerization is enabled with a low catalyst loading at higher temperature. Kilogram-scale depolymerization of over 300 complex multi-layered credit cards and the subsequent recovery of the metal components showed the high selectivity and tolerance of the system. The readily polymerizable isolated monomers confirmed the feasibility of the proposed circular economy.

Automated summary

The adoption of glycol-modified poly(ethylene terephthalate) (PET-G) as an alternative thermoplastic enables a transition from the current linear economy to a sustainable circular economy for non-recyclable multi-materials. Chemical recycling of PET-G is demonstrated for the first time, showcasing its effective depolymerization capabilities. The system exhibits high selectivity and tolerance, enabling kilogram-scale depolymerization and recovery of metal components from complex multi-layered credit cards.