One‐Pot Synthesis of Depolymerizable δ‐Lactone Based Vitrimers

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. Depolymerizable vitrimers are developed through a one‐pot synthesis approach. The low‐ceiling‐temperature polymer from the ring‐opening polymerization of the biobased δ‐lactone is cross‐linked with dynamic acetal linkages. The cross‐linked vitrimer allows reprocessing and healing and can easily depolymerize back to monomers for closed‐loop recycling. These vitrimers exhibit excellent properties, making them a biobased and sustainable replacement for conventional soft elastomers.