Comparison of 3D printer application and strength property using polylactic acid filaments with lignin-free and -rich MFC

This study applied microfibrillated cellulose (MFC)/polylactic acid (PLA) composite filaments made of lignin-free (F-MFC, 1.0% Klason lignin) and -rich (R-MFC, 4.5% Klason lignin) MFC in PLA as a matrix to three-dimensional (3D) printing. Further, the 3D printing quality and physical performance using the 3D printed test specimens was evaluated. Regardless of their lignin contents, both F-MFC and R-MFC showed good compatibility with PLA after a solvent exchange with tert-butyl alcohol, resulting to a better dispersion in methylene chloride. The cross-sectional area of the 3D printed specimen with the MFC/PLA filaments showed that the voids between the printed surfaces were decreased, leading to a better strength development. Thus, compared to the printed specimens from the neat PLA and commercial PLA filaments, the F-MFC/PLA filament specimen showed the highest strength, followed by that of the R-MFC/PLA filament. These results suggest that the solventexchanged MFC was well dispersed in the PLA matrix and produced a higher 3D printing quality and strength development, regardless of its lignin content.