Bio-based Recyclable Epoxy Vitrimers Prepared by The Combined Action of Cyclic Boroxine and Acylhydrazone Bonds

The preparation of high-performance recyclable epoxy vitrimer from bio-based feedstocks is of great industrial significance. Based on the above considerations, in this paper, we report a reaction of curing a bio-based epoxy monomer, propanetriol triglycidyl ether (GTE), with vanillin-derived diphenol monomer (VD) and 3-aminophenylboronic acid (M-APBA) as a curing agent, which resulted in the preparation of epoxy vitrimer films (EVB-X) with acylhydrazone bonds and cyclic boroxine dual dynamic response. Among them, the diphenol monomer VD supplies the flexible structure of the film, while the film showed a gradual increase in the boroxine six-membered ring structure with the gradual increase in the ratio of M-APBA, and the thermal and mechanical properties of the films are also gradually improving. By varying the ratio of VD to M-APBA in the material, EVB-3 was the most thermally stable, while T_g was measured at 45 °C, the highest tensile strength (57.40 MPa), and the largest cross-linking density (3271 mol/m³) among the four groups of films obtained from EVB-X films. In addition, the EVB films had excellent triple memory and could be largely degraded in acidic DMF and DMSO, with a gel content of 86.74% measured with EVB-3. Notably, the EVB scratches were completely healed at 100 °C for 1 h, indicating that EVB have excellent self-repairing properties, while the tensile strength could be recovered up to 28.98 MPa after heat treatment, and the strain repair rate could reach up to 89.42%, which provides good reprocessability.