Fast Damage-Healing of Rigid Photocuring 3D Printing Materials Capable of Directly Recycling in 3D Printing

Rigid 3D printing materials often get defects such as cavities, voids, holes, or gaps when suffering from impact forces. Fast self-healing of these damages without bulk temperature increase is always desired. Besides, the recycling of dynamically cross-linked polymers was usually focused on solvent- or heat-assisted strategies such as compression molding and dissolution-casting, which restricts the geometrical diversity of recycled materials and may cause environmental issues. Here we report a rigid photocuring 3D printing material that can heal its cave-like damage quickly under UV light based on the dynamic urea bond. Besides, after grounding the printed objects into powders and directly refilling them into new printing resin, the re-3D printed objects show similar mechanical properties to the original materials without any post-treatment.