Selective depolymerization of poly(ethylene terephthalate) for economical closed-loop recycling of mixed textiles

Polyethylene terephthalate (PET) is the second largest source of plastic wastes. An ideal solution is to chemically convert PET back into its monomers. Although many strategies have been reported, their extension towards PET-containing waste textiles is economically prohibitive. This is because chemical depolymerization can degrade multiple components in mixed textiles, yielding complex mixtures that are cost-prohibitive to separate and purify. Here, we report highly efficient processes that overcome this bottleneck. We find that, for thermally treated mixed textiles, the depolymerization of PET via methanolysis can be achieved in a rapid yet highly selective manner under mild conditions. This greatly simplifies the chemical recycling process, yielding high-purity DMT monomer ( ≥ 99.92%) at a yield of 91%. Techno-economic analysis shows that our strategy is economically competitive, suggesting a feasible closed-loop option for this indispensable commodity polymer. Recovering polymerization-grade monomers from waste textiles remains challenging. Here the authors report that the depolymerization of PET from thermally treated mixed textiles via methanolysis can be achieved in a rapid yet highly selective manner under mild conditions.