Three-Dimensional Printing of Lignocellulose Structures: Improving Mechanical Properties and Shape Fidelity

Additive manufacturing of nanocellulose (NC) materials is an emergent technological domain that facilitates the fabrication of complex and environment-friendly structures that mitigate greenhouse gas emissions. However, printing high concentrations of NC into intricate structures encounters substantial challenges due to inadequate adhesion between the printed layers attributed to a high cellulose solid content, resulting in low shape fidelity and mechanical properties. Therefore, to address these challenges, this paper reports lignin (LG) blending, a nanofiller, in high-content NC (>25 wt % solid content) paste to improve the layer adhesion of three-dimensional (3D) printed structures. The printed structures are dried in a clean room condition followed by postcuring. The optimized lignocellulose (0.5LG-NC) paste showed high structural shape fidelity, remarkable flexural strength, and moduli of 102.93 +/- 0.96 MPa and 9.05 +/- 0.07 GPa. Furthermore, the volumetric shrinkage behavior in box-like 3D printed structures with optimized LG-NC paste shows low standard deviations, demonstrating the repeatability of the printed structures. The study can be adapted for high-performance engineering and biomedical applications to manufacture high mechanical strength environment-friendly structures.