XanthoStarch: Advancing carbohydrate-enriched resins for 3D-Printing via PI-RAFT polymerization

• Carbohydrates are transformed into photoactive chain transfer agents (xanthates) by a modified viscose process. • Starch-based derivatives give fastest kinetics in photo-iniferter polymerization. • These polymers can be used as photo-active component in 3D-printing resins. • The use of renewable resources and valorization of sulfur makes this approach interesting for sustainable chemistry. The urgent demand for sustainable polymer technologies requires merging renewable feedstocks with advanced polymerization strategies. Xanthation, historically developed for viscose rayon production, provides a renewable pathway to functional polysaccharides while introducing xanthate groups that are inherently photoactive. Here, we demonstrate the duality of this chemistry by employing bio-based cellulose- and starch-derived xanthates as photoiniferters in reversible addition–fragmentation chain transfer (RAFT) polymerization. While cellulose-xanthate showed limited solubility in aqueous media, methylated derivatives enabled efficient light-induced polymerization in DMSO. Building upon these findings, starch-xanthate-methyl (Starch-Xan-Me) was synthesized as a more robust, soluble, and scalable alternative. Starch-Xan-Me exhibited clear photoactivity in UV–Vis experiments, allowed photopolymerizations verified by 1 H NMR, and enabled precise light-gated chain growth. The combination of Starch-Xan-Me with commercial PEGDA575 resulted in homogeneous formulations suitable for digital light processing (DLP) 3D printing. Real-time rheology revealed rapid curing kinetics, while post-curing studies (FTIR, DSC, and swelling) confirmed sufficient network stabilization within 300 s. Demonstrations on a commercial printer yielded high-quality objects with geometrical fidelity and reusability of the resin. These results establish carbohydrate-derived xanthates as renewable, oxygen-tolerant, and efficient photoiniferters, bridging the historical concept of rayon chemistry with emerging living 3D printing, and paving the way for sustainable and reconfigurable polymer systems.