Recyclable, Biobased Photoresins for 3D Printing Through Dynamic Imine Exchange

Transimination reactions are highly effective dynamic covalent reactions to enable reprocessability in thermosets, as they can undergo exchange without the need for catalysts, by exposing the materials to external stimuli such as heat. In this work, a series of five biobased vanillin-derived resin formulations consisting of vanillin acrylate with vanillin methacrylate-functionalized Jeffamines were synthesized and 3D-printed using digital light projection (DLP). The resulting thermosets displayed a range of mechanical properties (Young's modulus 2.05-332 MPa), which allow for an array of applications. The materials we obtained have self-healing abilities, which were characterized by scratch healing tests. Additionally, dynamic transimination reactions enable these thermosets to be reprocessed when thermally treated above their glass transition temperatures under high pressures using a hot press. Due to the simple synthetic procedures and the readily available commercial Jeffamines, these materials will aid in promoting a shift to materials with predominantly biobased content and help drift away from polymers made from non-renewable resources.