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

In this study, a novel self-healing, chemically degradable and recyclable vanillin vitrimers (VFx) 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 VFx, VF10 containing 10 mol % disulfide bonds exhibited the best mechanical properties (T-g = 43 degrees C, tensile strength = 16.68 MPa), and the mechanical properties were sustained after two cycles of hot pressing. More significantly, VFx 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.