Preparation of environmentally friendly bio-based vitrimers from vanillin derivatives by introducing two types of dynamic covalent C[dbnd]N and S–S bonds

In this study, a novel self-healing, chemically degradable and recyclable vanillin vitrimers (VF_x) containing multiple reversible covalent bonds were prepared from vanillin-derived dialdehyde and amine monomers. In order to improve mechanical properties and shorten the relaxation time, we introduced disulfide bonds into the polyschiff vitrimers. Among these VF_x, VF₁₀ containing 10 mol % disulfide bonds exhibited the best mechanical properties (T_g = 43 °C, tensile strength = 16.68 MPa), and the mechanical properties were sustained after two cycles of hot pressing. More significantly, VF_x could be degraded in hydrochloric solution (pH = 2) and recycled to prepare the films. These characteristics of reprocessability, recyclability and bio-based monomer present a feasible way to satisfy the demands of sustainability, which is of great significance for the recycling of resources.