Super-Tough and Resilient Recyclable Polyester Elastomers Enabled by Dynamic Cross-Linking

Although recyclable polymers have offered a promising solution to concerns about our environment and sustainability, developing elastomeric materials that simultaneously possess strong toughness and excellent resilience remains a significant challenge. To address this, a recyclable polyester elastomer is reported by the strategic Diels–Alder reaction between a furan-based amorphous polyester copolymer and a maleimide cross-linker, thereby overcoming the traditional trade-off between mechanical strength and resilience. The resulting elastomer exhibits ultratoughness (201 MJ m–3) and resilience in the first extension stress (89%), which are 2–3.3 times and 1.4–1.6 times higher than those of commercial polyolefin-based TPEs, respectively. In addition, the cyclohexene linkage moieties endow the elastomers with unique dynamic characteristics, including self-healing capabilities and shape reconfigurability, thus significantly increasing the design flexibility and versatility of complex structures. They also have wide service temperature ranges (−50–105 °C), high temperature stability (Td,5% = 358 °C), and reasonably wide thermal reprocessing windows (105–358 °C). Thermolysis of the bulk elastomer at 150 °C can recover 95 wt % of the material, allowing reuse without losing value and achieving a successful closed-loop life cycle.