High-Performance and Closed-Loop Recyclable Thermoplastic Elastomers from Sequential Ring-Opening Copolymerization of Biobased β-Methyl-δ-valerolactone and <i>p</i> -Dioxanone

Despite the great advancements achieved for the closed-loop recyclable thermoplastics in the past decade, it remains a big challenge to develop thermoplastic elastomers (TPEs) combining closed-loop recyclability and good performance. In this contribution, a series of PPDO-b-PβMVL-b-PPDO triblock copolymers are successfully prepared by sequential ring-opening copolymerization of biobased β-methyl-δ-valerolactone (βMVL) and p-dioxanone (PDO). The obtained triblock copolymers demonstrate comprehensive mechanical properties comparable to those of commercial styrenic TPEs. Specifically, the obtained TPEs exhibit an excellent tensile strength up to 21 MPa, a high elongation at break up to 1054%, and a high elastic recovery up to 93.5%, as well as a wide operational temperature range from −45.2 to 81.3 °C. Notably, these triblock copolymers can be depolymerized in bulk to recover the original monomers by distillation with an overall high yield of 94%. The recovered monomers can be used for repolymerization to afford TPEs with performances comparable to those of the original materials, thus establishing a closed-loop life cycle.