Effects of MFC Dispersionability on the Physical and Thermal Properties of Filaments in the Production of 3D Printing Filament

In this study, thermal and physical properties of the 3D filaments fabricated with micro- fibrillated cellulose (MFC) reinforced polylactic acid (PLA) for fused deposition modeling (FDM) 3D printer were investigated. In order to produce a good dispersed filament of hy- drophilic MFCs derived from lignin-less (F-MFC) and lignin-rich (R-MFC) fibers in a hydrophobic PLA matrix, two different dispersion methods were compared. The Type 1 method was powder-type MFCs and PLA fibers were simply mixed with inside an extruder and then MFC-reinforced filaments were produced at a given production condition. Another was the mixture of MFCs with a PLA solution dissolved in dichloromethane was dried into a complex form which was fed into the extruder to produce Type 2 filaments. It was confirmed through FE-SEM images that the hydrophilic MFC and hydrophobic PLA were uniformly distributed in the Type 2 filaments rather than Type 1 filaments. Also Type 2 filaments showed higher values in the tensile strength and elongation at break and a lower melting peak than those of Type 1 and neat PLA filaments. In addition, the filament derived from the lignin-less MFC (F-MFC) with the Type 2 method had the highest tensile strength and elongation at break and showed one melt peak between 50-2501), suggesting a better dispersion of MFC in the hydrophobic matrix.