Biobased Photopolymer Resin for 3D Printing Containing Dynamic Imine Bonds for Fast Reprocessability

Acrylic photopolymer resins are widely used in stereolithographic3D printing. However, the growing demand for such thermosetting resinsis weighing on global issues such as waste management and fossil fuelconsumption. Therefore, there is an increasing demand for reactivecomponents that are biobased and enable recyclability of the resultingthermoset products. In this work, the synthesis of a photo-cross-linkablemolecule containing dynamic imine bonds based on biobased vanillinand dimer fatty diamine is described. Using the biobased buildingblocks, formulations containing reactive diluent and a photoinitiatorwere prepared. The mixtures could be rapidly cross-linked under UVlight, yielding vitrimers. Using digital light processing, 3D-printedparts were prepared, which were rigid, thermally stable, and reprocessedwithin 5 min at elevated temperature and pressure. The addition ofa building block containing a higher concentration of imine bondsaccelerated the stress relaxation and improved the mechanical rigidityof the vitrimers. This work will contribute to the development ofbiobased and recyclable 3D-printed resins to facilitate the transitionto a circular economy.