Vat 3D Printing of Bioderivable Photoresins - Toward Sustainable and Robust Thermoplastic Parts

Vat photopolymerization 3D printing (3DP) of thermoplastic materials is exceedingly difficult due to the typical reliance on cross-linking to form well-defined, solid objects on timescales relevant to 3DP. Additionally, photoresin build materials overwhelmingly rely upon nonrenewable feedstocks. To address these challenges, we report the vat 3DP of bioderivable photoresins that produced thermoplastic parts with highly tunable thermal and mechanical properties. The photoresins were formulated from two monomers that are easily obtainable from lignin deconstruction: 4-propylguaiacyl acrylate (4-pGA) and syringyl methacrylate (SMA). These bioderivable materials generated printed parts that ranged from soft elastomers to rigid plastics. For example, for 4-pGA-based materials, the breaking stresses varied from 0.20 to 20 MPa and breaking strains could be tuned from 4.7% up to 1700%, whereas 3D-printed SMA-based materials resulted in higher breaking stresses (similar to 30 MPa) and T(g)s (similar to 132 degrees C). Notably, parts printed from these bioderivable formulations exhibited thermoplastic behavior and were largely soluble in common organic solvents-expanding the application and repurposing of the 3D-printed parts. We highlight this feature by reusing a 3DP part via solvent casting. Overall, the tunable properties and thermoplastic behavior of the lignin-derivable photoresins showcase renewable lignin resources as promising biofeedstocks for sustainable 3DP.