Dual Dynamically Cross-Linked Epoxy Resin Vitrimer from Biobased Material Vanillin with Excellent Mechanical Properties, Fast Reprocessability, and Rapid Acid-Responsive Degradability

The incorporation of dynamic covalent networks into epoxy resins is an effective strategy to overcome their inherent limitations of nonreprocessability and nondegradability, leading to a class of materials known as epoxy vitrimers. Despite recent progress in achieving rapid reprocessability and degradability, epoxy vitrimers still face challenges, including inadequate mechanical properties and the prevalent use of the toxic precursor bisphenol A diglycidyl ether (BADGE). Herein, we report a one-pot synthesis of a biobased epoxy vitrimer using vanillin, diamino-functionalized phenylenediboronic ester (DPDBE), and polyether amine (PEA), which incorporates dual dynamic covalent bonds of the imine and boronic ester. The resulting vitrimer exhibits a remarkable combination of high mechanical strength and good toughness, achieving a tensile strength of 73 MPa with an elongation at break of 23%. This excellent mechanical performance is attributed to the molecular design: the conjugation between the imine bonds and benzene rings, the rigidity of the boronic ester five-membered rings, and the flexible ether bonds and long methylene chains from PEA. Furthermore, the synergistic effect between the imine and boronate ester bonds enables an exceptionally low activation energy (Ea) of 58.1 kJ/mol for the bond exchange reactions, resulting in rapid reprocessability within 5 min and complete degradation within 30 min. This work presents a promising strategy for developing high-performance, environmentally friendly epoxy vitrimers from sustainable resources.