2026-05-26 エディンバラ大学
＜関連情報＞
- https://www.ed.ac.uk/news/upcycling-method-offers-plastic-waste-solution
- https://www.cell.com/chem-circularity/fulltext/S3051-2948(26)00025-3
カルボニル基からチオカルボニル基への編集によるポリエステルの形態変化によるポリマー寿命の調整 Polyester metamorphosis via carbonyl-to-thiocarbonyl editing to tune polymer lifetime
Max J.S. Hill ∙ Janna Jeschke ∙ Hatice Mutlu ∙ Jennifer A. Garden
Chem Circularity Published:May 21, 2026
DOI:https://doi.org/10.1016/j.checir.2026.100029
Graphical abstract
Context & scale
Plastics remain indispensable yet environmentally persistent materials, and these characteristics highlight the urgent need for polymers that are fit for function but possess inherently tunable degradability. Aliphatic polyesters are promising replacements for commodity polymers, as they feature hydrolyzable ester bonds as functional degradation handles. Despite this enhanced degradability, degradation still often occurs on timescales exceeding those required to effectively tackle the global plastic waste crisis, and the material properties of aliphatic polyesters remain largely limited to those accessible from common polyesters such as poly(ε-caprolactone) and poly(lactic acid). To this end, there is growing interest in moving beyond traditional polyesters toward alternative material classes, such as sulfur-containing equivalents, that better meet broad-ranging material property requirements as well as idealized degradation criteria. While extensive work has explored the incorporation of sulfur into common cyclic monomers, with subsequent polymerization into polythioesters and polythionoesters, this approach introduces issues of poor monomer stability and selectivity challenges due to O/S exchange in the polymer backbone. This work unlocks an alternative post-polymerization metamorphosis strategy that enables direct modification of poly(ε-caprolactone), thus circumnavigating these synthetic challenges to provide a direct route to high-molecular-weight polythionoesters. This straightforward and adaptable method harnesses established knowledge and advancements along with innovation from within the polyester field, ultimately resulting in a procedure where the degree of thionation is tunable and the process is scalable from 100 mg to a 10 g, with opportunities for further scale-up. Initial proof-of-concept degradation studies demonstrate that ester carbonyl-to-thiocarbonyl editing can enhance polymer degradation under acidic conditions, and future studies should investigate comprehensive environmental degradation studies as well as assess the environmental impact of degradation products. Overall, this strategy demonstrates how polymer-analog modification can expand the functional landscape of existing polyester materials, thereby enabling flexible adaptation of polymer material properties and contributing to polymer circularity via post-polymerization upcycling as well as controlled tuning of the degradability of existing polyester feedstocks.
Highlights
- Polyester metamorphosis via post-polymerization thionation
- Tunable material properties at high molar mass (80 kDa) and gram scale
- Selective PCL metamorphosis in block and random PCL-PLA
- Polythionoesters show enhanced degradation vs. polyesters
Summary
Aliphatic polyesters such as poly(ε-caprolactone) (PCL) and polylactic acid (PLA) are biodegradable alternatives to conventional polymers, but their environmental degradation is often slow. This work introduces a polyester metamorphosis strategy for editing carbonyl-to-thiocarbonyl bonds in order to convert commercial polyesters into their sulfur-rich analogs, polythionoesters (–(C=S)–O–). This underexplored class of materials is not easily accessible from sulfur-containing monomers due to monomer instability and purification challenges. This work circumnavigates these issues by achieving the first post-polymerization thionation of PCL derivatives. Controlled degrees of thionation with Lawesson’s reagent allow systematic tuning of crystallinity, thermal transitions, and degradation. PLA resists thionation, a feature that enables selective modification of PCL domains in PCL-PLA copolymers. The resulting polythionoesters display accelerated degradation compared with polyester analogs, a characteristic that demonstrates how carbonyl-to-thiocarbonyl bond editing systematically tunes polymer lifetimes and properties. Beyond degradability, thiocarbonyl motifs provide opportunities in photochemistry, coordination chemistry, and catalysis, all of which highlights polyester metamorphosis as a versatile platform for polymer upcycling and functional diversification.
