Effect of the cellulose nanofiber on ultraviolet curable resin for additive manufacturing: Mechanical properties and printability

Cellulose nanofiber incorporated into vat photopolymerization technology has garnered significant attention as an eco-friendly reinforcement owing to its high mechanical properties and biocompatibility. However, several notable challenges still remain, particularly concerning the feasibility of handling complex geometries. In this study, we present a vat photopolymerization resin enhanced with CNF. To assess printability on a standard 3D printer, various formulations were created by adjusting the CNF content, and their rheological properties were measured. Subsequently, specimens with different constraints were prepared to evaluate the impact of CNF content on printability. The mechanical properties of the 3D printed composites were assessed using tensile/ flexural tests and morphology analysis was conducted by using micro-CT and scanning electron microscope. The findings revealed that a 0.5 wt% CNF-reinforced resin successfully produced intricate geometries with exceptional mechanical strength. These results underscore the importance of determining an optimal reinforcement content to ensure both printability and desirable mechanical properties. Furthermore, this study serves as inspiration for incorporating other fibers into vat photopolymerization processes.