Digital light processing 3D printing: Harnessing micro- and nanocellulose for advanced biocomposites.

The integration of sustainable materials into additive manufacturing is critical for advancing environmentally responsible technologies. In this study, we demonstrate a novel approach to enhancing digital light processing (DLP) 3D printing resins by incorporating octenylsuccinic anhydride (OSA)-modified cellulose fillers-specifically, microcrystalline cellulose (Avicel-PH) and cellulose nanocrystals (CNC-PH). This is the first comparative investigation of these two hydrophobized cellulose types as bio-based reinforcements in DLP resins. The OSA modification significantly improved filler compatibility and dispersion within the resin matrix, with CNC-PH outperforming due to its nanoscale structure. Notably, CNC-PH at 10-15 wt% content yielded a 336 % increase in tensile modulus, while Avicel-PH showed a 314 % improvement, underscoring the effectiveness of nanoscale reinforcement. Thermal analysis confirmed enhanced thermal stability and reduced char formation, while SEM imaging revealed uniform morphology and strong filler-resin interaction. These results underscore the potential of surface-modified nanocellulose to develop high-performance, eco-friendly DLP biocomposites, setting a new direction for sustainable additive manufacturing.