Sustainable Urushiol-Based Vitrimers Capable of Fast Self-Repairing and Shape Memory via Double Dynamic Covalent Bonds

In this study, a dual dynamic covalent bonding system, consisting of disulfide and hydroxyl-ester bonds, was introduced into a urushiol-based vitrimer network. Vitrimers (ODD) with different content systems of 2,2′-dithiobisbenzoic acid (DTSA) were prepared by combining oxidized urushiol glycidyl ether (OUGE) with dimeric acid (DA) and DTSA after the oxidation of double bonds. The material structure was analyzed by using Fourier transform infrared (FTIR) spectroscopy, while the mechanical, self-healing, shape memory, and thermal properties were evaluated by using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), thermogravimetric analysis (TGA), a universal testing machine, optical microscopy, and other characterization techniques. Due to the introduction of more covalent bonds in the system, rapid stress relaxation was observed, with a relaxation time of only 15 s at 180 °C. In terms of self-repair performance, the repair was almost completed in only 30 min. In terms of chemical degradation, incomplete degradation occurs when ethylene glycol is used due to the presence of disulfide bonds in the system.