Dual Recycling of Depolymerization Catalyst and Biodegradable Polyester that Markedly Outperforms Polyolefins

• Published in: Angewandte Chemie 2023-06, Vol.135 (26), p.n/a
• Main Authors: Li, Xin‐Lei, Clarke, Ryan W., An, Hai‐Yan, Gowda, Ravikumar R., Jiang, Jing‐Yang, Xu, Tie‐Qi, Chen, Eugene Y.‐X.
• Format: Article
• Language: English
• Subjects: Biodegradability; Biodegradation; Catalysts; Catalytic activity; Chemistry; Depolymerization; High temperature; Inorganic Polyacid; Mechanical properties; Metal-Catalyst; Molecular weight; Monomers; Phosphomolybdic acid; Polymers; Polyolefins; Recyclable Polyester; Recycling; Recycling systems; Ring-Opening Polymerization; Temperature requirements; Tensile strength; Thermoplastic
• ISSN: 0044-8249; 1521-3757
• DOI: 10.1002/ange.202303791

Chemically recyclable, circular polymers continue to attract increasing attention, but rendering both catalysts for depolymerization and high‐performance polymers recyclable is a more sustainable yet challenging goal. Here we introduce a dual catalyst/polymer recycling system in that recyclable inorganic phosphomolybdic acid catalyzes selective depolymerization of high‐ceiling‐temperature biodegradable poly(δ‐valerolactone) in bulk phase, which, upon reaching suitable molecular weight, exhibits outstanding mechanical performance with a high tensile strength of ≈66.6 MPa, fracture strain of ≈904 %, and toughness of ≈308 MJ m−3, and thus markedly outperforms commodity polyolefins, recovering its monomer in pure state and quantitative yield at only 100 °C. In sharp contrast, the uncatalyzed depolymerization not only requires a high temperature of >310 °C but is also low yielding and non‐selective. Importantly, the recovered monomer can be repolymerized as is to reproduce the same polymer, thereby closing the circular loop, and the recycled catalyst can be reused repeatedly for depolymerization runs without loss of its catalytic activity and efficiency. Dual recycling of the potent depolymerization catalyst PMA and biodegradable polyester PVL that largely outperforms commodity polyolefins has been achieved. The chemical recycling of PVL in bulk phase is performed under mild temperature of only 100 °C, recovering the pure monomer in quantitative yield for closed‐loop recycling and the depolymerization catalyst that can be reused repeatedly without loss of activity and efficiency.