Cellulose nanofiber-introduced continuous-ramie yarn-reinforced polylactic acid filament for 3D printing: Novel fabrication process and mechanical properties

Abstract

This study focused on reinforcing the interface of continuous-ramie yarn-reinforced polylactic acid (PLA) filaments with cellulose nanofibers (CNFs) for 3D printing applications. To realize the reinforcement effect of CNFs, the distribution of dispersed CNFs at the surface of ramie fiber is necessary. Thus, we developed a new false-untwisting process to enable the continuous dip-coating of CNF slurry while the ramie yarn is untwisted yarn. This study was designed to reveal the influence of the false-untwisting process and CNF content on the surface morphology of the processed yarn and on the mechanical properties of the yarn–PLA composite filaments. We found that the false-untwisting process achieved the formation of fuzzy CNFs. Furthermore, the tensile strength and Young’s modulus of the filaments were improved by up to 20.0% and 26.6%, respectively, compared to those of ramie yarn-reinforced PLA filaments without CNFs.