A Bio-Based Photopolymer Resin Enabled by Sulfur-Mediated Dynamic Network for High-Resolution Printing and Chemical Recovery

Developing photopolymer resins that combine renewable sourcing, robust mechanical performance, and viable end-of-life recovery within a simple formulation remains a key challenge for sustainable polymer chemistry. Here, we report a bio-based photopolymer resin, EugLA, synthesized from eugenol and lipoic acid through a concise one-step esterification and designed to enable chemical recovery and reprocessing. The resin employs a dual-cure strategy in which ultraviolet (UV) irradiation first fixes the printed geometry, while subsequent thermal treatment at 60 °C drives sulfur-mediated network reorganization, generating a hybrid architecture that integrates dynamic S−S bonds with reinforcing C−S-containing linkages. Spectroscopic and thermomechanical characterization indicates that this reorganization not only provides a structural basis for network recovery and reprocessing, but also progressively strengthens the network, reaching an optimal state after 24 h of post-curing with a tensile strength of 25.9 MPa and a favorable strength−ductility balance. Owing to its good storage stability, workable viscosity, and well-defined curing response, the resin supports digital light processing (DLP) fabrication of complex three-dimensional architectures and high-resolution microfeatures at the 20−30 μm scale. In addition, EugLA demonstrates resin-assisted welding, chemical recovery of the crosslinked network, and proof-of-concept reprinting. This work offers a strategy for designing sustainable photocurable resins by coupling renewable monomer design with sulfur-mediated dynamic network evolution to integrate mechanical performance, processability, and chemical recovery.