Development of Bio-Based Composites made with Chemically Modified Cellulose Nanofibrils for 3D Printing Purposes

Abstract

Cellulose nanofibrils (CNF) have been used to improve the strength and functionality of various materials, such as lightweight composites and eco-friendly packaging. However, their use in 3D printing is still under research. CNF is derived from wood pulp and have a tendency to aggregate making their use challenging. This research focuses on modifying CNF surfaces to overcome this issue and make them suitable for 3D printing.

The study successfully extracted CNF from wood pulp and modified its surface to prevent aggregation. By adding chemical groups to CNF, it becomes more stable and easier to blend with other materials. One method involved grafting a hydrophobic (water-repellent) substance onto CNF, making it compatible with non-polar plastics like high-density polyethylene (HDPE). This modified CNF (CNF-g-SA) improved the plastic's stiffness and reduced warping during 3D printing, leading to better shape accuracy.

Another part of the research explored creating a self-healing gel using modified CNF. This gel, made by combining CNF with a special copolymer, showed improved mechanical properties and the ability to heal itself when heated, making it useful for 3D printing complex objects with high resolution.

Lastly, the study developed a 3D printable gel using a peptide (Fmoc-FF) combined with CNF. The resulting composites had improved mechanical properties and printability, allowing the creation of detailed 3D objects that retained their shape well after drying.

Overall, the research demonstrated that modifying CNF surfaces enhances their compatibility with various materials, making them suitable for advanced 3D printing applications and leading to stronger, more flexible, and eco-friendly printed objects.