Plasticizer Combinations and Performance of Wood Flour–Poly(Lactic Acid) 3D Printing Filaments

Abstract

Wood flour-poly(lactic acid) 3D printing filaments were prepared via a melt extrusion method. Poplar wood flour and poly(lactic acid) (PLA) were used as raw materials, and different combinations of glycerol and tributyl citrate (TBC) (4% glycerol, 2% glycerol + 2% TBC, 4% TBC) were used as plasticizers. A 3D printer was used to print the filaments into standard test specimens with dimensions of 150 mm × 10 mm × 0.2 mm at the printing temperature of 220 °C. The performance of wood flour-poly(lactic acid) 3D printing filaments in terms of their interfacial compatibility, mechanical properties, melt index (MI), water absorption, and heat stability was tested under different plasticizer combinations. The results showed that under the condition of same dosage of plasticizer, the order of MI for the 3D printed filaments from high to low was 4% glycerol > 2% glycerol + 2% TBC > 4% TBC, which indicated that glycerol was more favorable for the extrusion processing of the composite filaments. However, in terms of compatibility, mechanical properties, water absorption, and thermal stability, the 3D printing filaments with 4% TBC showed better performance compared with other groups.