Tuning the Photoreactivity of Renewable Resins Derived from Sustainable Terpenes and Glycerol via Multi-Arm Monomer Approach

The emergence of VAT photopolymerization spawned from the interest in manufacturing 3D objects with intricate geometries through the crosslinking of liquid resins under controlled light irradiation. Resin formulations based on (meth)acrylates and epoxides have remained at the forefront of the field owing to their rapid photoreactivity and ability to yield materials with tunable mechanical performance. However, the inherent nonbiodegradability of the resultant networks, combined with the nonrenewable nature of most vinyl monomers, has sparked growing interest in developing sustainable alternatives for VAT photopolymerization. Here, we report a library of photocurable resins derived from renewable terpenes, glycerol, and a commercial thiol for use in digital light processing. To achieve resins with fast photocuring kinetics and good printability, multi-arm terpene-based monomers were designed to systematically vary the level of alkene functionality in the system. Synthetic approaches were straightforward and readily scalable, while resin gelation was greatly affected by increasing the number of arms in the terpene-based monomers. Soft networks with moderate strength (1.4–5 MPa) and elongation at break (88–164%) were obtained, and printing resolution of solvent-free resins decreased in systems of higher viscosity. This study demonstrates a more sustainable alternative to conventional DLP resins, yielding networks that incorporate renewable content and exhibit potential hydrolytic degradability.