3D printing of cellulose nanofiber/polylactic acid composites via an efficient dispersion method

In this study, a green and efficient dispersion method was developed to prepare cellulose nanofiber (CNF) reinforced polylactic acid (PLA) composites for fused deposition modeling (FDM) 3D printing. The CNF/PLA compounds were readily obtained by blending a CNF aqueous suspension with microscale PLA powder, followed by an air-drying process. This method significantly reduced the need for chemical reagents and shortened the processing time. A silane coupling agent and polyethylene glycol (PEG) were used as surface modifiers to enhance the dispersion of CNFs in PLA matrix, and the interfacial interactions between the two constituents in the composite. The CNF/PLA composite filaments for 3D printing were produced using twin-screw cycling extrusion. The test results showed that the incorporation of the surface-modified CNFs effectively enhanced the flowability and the mechanical performance of PLA. The superior mechanical properties of the resulting 3D-printed CNF/PLA composites can be attributed to the uniform dispersion of CNFs in the PLA matrix, higher crystallinity of PLA, and reduced composite defects.