Vanillin-Based Polyschiff Vitrimers: Reprocessability and Chemical Recyclability

In this study, dynamic imine covalent bonds were introduced into vanillin-based vitrimers networks, endowing thermosets with hot-reprocessing ability and chemical recyclability under acid hydrolysis. First, dialdehyde monomer, which was synthesized from lignin-derived vanillin monomer, was reacted with conventional amine cross-linkers to form dynamic imine bond networks. Even after three hot-processing cycles, the tensile strength and elongation at break of polyschiff vitrimers could be recovered at least up to 71.2 and 72.8%, respectively, through the imine metathesis reaction. Importantly, the dialdehyde monomers showed enhanced recyclability under strong acid solution and could be reused to regenerate polyschiff vitrimers. These characteristics of reprocessablility, recyclablility, and biobased monomer present a feasible way to satisfy the demands of sustainability.