One‐Pot Synthesis of Depolymerizable δ‐Lactone Based Vitrimers

Abstract

A depolymerizable vitrimer that allows both reprocessability and monomer recovery by a simple and scalable one‐pot two‐step synthesis of vitrimers from cyclic lactones is reported. Biobased δ‐valerolactone with alkyl substituents (δ‐lactone) has low ceiling temperature; thus, their ring‐opening‐polymerized aliphatic polyesters are capable of depolymerizing back to monomers. In this work, the amorphous poly(δ‐lactone) is solidified into an elastomer (i.e., δ‐lactone vitrimer) by a vinyl ether cross‐linker with dynamic acetal linkages, giving the merits of reprocessing and healing. Thermolysis of the bulk δ‐lactone vitrimer at 200 °C can recover 85–90 wt% of the material, allowing reuse without losing value and achieving a successful closed‐loop life cycle. It further demonstrates that the new vitrimer has excellent properties, with the potential to serve as a biobased and sustainable replacement of conventional soft elastomers for various applications such as lenses, mold materials, soft robots, and microfluidic devices.

Recyclable and (Bio)degradable Polyesters in a Circular Plastics Economy

“…In 2023, Qi and co-workers reported a polyester-based vitrimer capable of both reprocessability and chemical recycling, achieved through a simple and scalable one-pot two-step synthesis from biobased δ-lactones with three distinct alkyl substituents (δ-lactone: δ-1, δ-4, δ-7) (Schemes 39 and 41). 475 DPP was employed for the controlled ROP of δlactones and was also found to effectively catalyze the click reaction between vinyl ethers and alcohols. As a result, the synthesized poly(δ-lactone) triols, initiated from glycerol, can be directly used for cross-linking without requiring any additional post-treatment steps.…”

“…Each poly(δ-lactone) vitrimer was efficiently recovered back to its constituent monomers with yields of 85−90% within 1 h through thermolysis at 200 °C under reduced pressure. 475 Upon heating to 200 °C, the acetal cross-linkages of the poly(δ-lactone) vitrimers underwent decomposition, producing 1,4-cyclohexanedimethanol and acetaldehyde, which then evaporated. This resulted in the formation of hydroxyl-capped aliphatic polyesters, poly(δ-lactone) triols, which were subsequently depolymerized back to monomer.…”

Recycling of Epoxy Resins with Degradable Structures or Dynamic Cross-Linking Networks: A Review

“…The application of ester groups has a long history in polymers. The degradation of compounds or polymers including ester groups has such abundant pathways as acid degradation, , alkali degradation, , ester exchange degradation, , thermal degradation, biodegradation, , and microwave-assisted degradation . This section mainly introduces the chemical properties of carboxylic esters, lactones, and sulfonate esters (Chart ), and their applications in degradable polymer materials.…”

Closed-loop recycling of lignin-based sustainable polymers with an all-hydrocarbon backbone

“…, ester bonds and ether bonds) to the polymer backbone, which serve as the key scission sites during degradation. 4–10 These labile chemical bonds could also lead to undesirable mechanical performance reduction and depressed thermal stability compared with polyolefins. 11…”