Effect of infill value on decay resistance, thermal, and mechanical properties of 3D printed polylactic acid composites filled with wood fibers
Polylactic acid (PLA)-based composites with wood filler were 3D-printed using fused deposition modeling (FDM) at different infill settings (i.e., 10 to 100%) to evaluate their strength and biodegradation properties. Microvoids were present in the commercial wood-filled PLA filaments. Wood-PLA filament had reduced thermal stability compared with mineral-filled PLA filament due to the presence of thermally degradable wood flour. The printed composites had a denser internal structure with increased infill. The flexural modulus of elasticity and modulus of rupture also increased with infill value. Sixteen-week fungi test performed using a brown rot, Postia placenta, and a white rot, Irpex lacteus, did not lead to significant sample weight loss and strength reduction for composites at various infill values. Therefore, 3D printed composites with PLA-based filament containing 30 wt.% wood fiber were shown to be resistant to biodegradation by common decay fungi.