Robust, UV-resistant and transparent vitrimers from bio-based mercaptan via maleimide–thiol “click” chemistry for carbon fiber-reinforced polymer composites

Abstract

A series of transparent bio-based vitrimers with strong UV-shielding performance have been successfully prepared through a maleimide–thiol “click” reaction between bio-based thiols and bismaleimide (BMI). Tri- and tetra-functional thiol monomers (G-3SH and E-4SH) were synthesized via esterification of glycerol or erythritol with 3-mercaptopropionic acid and subsequently cross-linked with BMI to form networks containing dynamic C–S bonds. The resulting vitrimers show excellent mechanical properties (tensile strength up to 87.4 MPa), high thermal stability (initial decomposition temperature above 330 °C), and nearly complete UV-blocking across the full UV range (200–400 nm). Benefitting from the exchangeable C–S bonds, these materials exhibit efficient self-healing (healing efficiency up to 98.7%), welding, reprocessability, and chemical recycling. Furthermore, carbon fiber-reinforced polymer (CFRP) composites fabricated using these vitrimer matrices can be fully degraded under mild conditions, enabling the recovery of intact carbon fibers and the re-manufacturing of composites that possess comparable mechanical performance to the original material. This work provides a viable strategy for developing sustainable, high-performance, and recyclable thermosets and their composites for advanced structural applications.