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

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.