Strongly adhesive and sustainable photopolymers via reaction-sequenced network design

Photopolymers enable rapid curing and digital manufacturing but are typically constrained by a trade-off between mechanical robustness, interfacial adaptability, and sustainable design. Here, we develop a reaction-sequenced photopolymerization strategy that kinetically separates distinct network-forming pathways during curing. Rapid free-radical polymerization constructs an initial load-bearing acrylate network, while the delayed formation of an epoxy network provides an energy-dissipating phase. A renewable cellulose component reinforces interfacial adhesion through synergistic interactions with both polymer networks, facilitating efficient stress dissipation. This bio-based adhesive achieves a lap-shear strength of 17.7 MPa at 30 wt% cellulose, demonstrating that high biomass incorporation is compatible with superior bonding performance. Crucially, the system retains rapid, solvent-free curing and stereolithographic compatibility, underscoring its potential for sustainable, high-performance manufacturing. Collectively, this work establishes a general reaction-sequenced design framework that reconciles mechanical performance with high renewable content, offering a sustainable pathway for engineering next-generation photopolymer systems.