Recyclable and Biodegradable Thermosets for 3D Printing via an Acid‐Labile Multifunctional Photoinitiator

ABSTRACT Thermosetting resins dominate the 3D printing market but pose significant sustainability issues due to their crosslinked, non‐degradable nature. We overcome these challenges with a novel multifunctional photoinitiator that polymerizes monofunctional acrylates into acid‐degradable thermosets. This approach enables the high‐resolution 3D printing of complex structures. Crucially, the materials are both recyclable and biodegradable. Post‐degradation, the linear polymers can be dissolved in fresh monomers and re‐cured, yielding materials with enhanced mechanical properties. Furthermore, the printed objects degrade in weakly acidic soil (pH 6) in approximately 75 days, and their degradation products show negligible ecotoxicity. This presents a promising and universal strategy for creating high‐performance, sustainable thermosets for 3D printing.