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

Rigid3D printing materials often get defects such as cavities,voids, holes, or gaps when suffering from impact forces. Fast self-healingof these damages without bulk temperature increase is always desired.Besides, the recycling of dynamically cross-linked polymers was usuallyfocused on solvent- or heat-assisted strategies such as compressionmolding and dissolution-casting, which restricts the geometrical diversityof recycled materials and may cause environmental issues. Here wereport a rigid photocuring 3D printing material that can heal itscave-like damage quickly under UV light based on the dynamic ureabond. Besides, after grounding the printed objects into powders anddirectly refilling them into new printing resin, the re-3D printedobjects show similar mechanical properties to the original materialswithout any post-treatment.