Overcoming Hydrophobicity with Water Enables Ultrafast Hydrolysis of Waste Polyethylene Terephthalate at Very Mild Conditions.

ABSTRACT: Chemical recycling of plastics holds great promise but remains constrained by sustainability issues, with polyethylene terephthalate (PET) epitomizing this challenge. Herein, we introduce a conceptually novel strategy that overcomes PET's intrinsic hydrophobicity by physically re-engineering the polymer's microstructure to enable ultrafast alkaline hydrolysis under exceptionally mild conditions. We leverage the ability of propylene carbonate (PC)-an inexpensive, commercial, green solvent-to selectively dissolve PET, to thermally induce phase separation, and subsequently act as a carrier for water insertion between polymer chains. Upon complete PC replacement, the water uptake exceeds twice the polymer mass, preventing chain re-compaction and establishing an interfacial environment that facilitates hydroxyl ion diffusion to ester bonds and depolymerization with minimal alkali consumption. As a result, water-swollen PET fully depolymerizes (96% TPA yield) at atmospheric pressure within 5 min at 90 ∘C$^{\circ }{\rm C}$ or under 2 h at room temperature, vastly outperforming conventional hydrolysis methods. The process achieves a >$>$ 20-fold reduction in energy footprint versus direct PET hydrolysis. It performs robustly on challenging, real-world feedstocks-including textiles and mixed plastic waste-enabling selective depolymerization unaffected by PET crystallinity. A techno-economic analysis (TEA) confirms energy efficiency and strong economic feasibility, demonstrating overall competitiveness with existing engineered technologies. Beyond PET, the physical mechanism underpinning the strategy offers a scalable and sustainable platform for recycling a wide range of condensation polymers.

SUBMITTER: Millucci F 

PROVIDER: S-EPMC12759205 | biostudies-literature | 2026 Jan

REPOSITORIES: biostudies-literature