(6fj) 3D Printing of Polylactic Acid Mixed with Wood

Teaching Interests: Mass and energy balances, chemical reaction engineering, biochemical and bioprocess engineering, thermodynamics

Abstract:

Polylactic acid (PLA) is a popular choice of plastic material for 3D printing. Incorporation of lignocellulosic biomass in this biodegradable plastic can increase utilization of waste plant material and manufacturing of cheaper 3D-printed biocomposites. However, mixing this hydrophobic plastic with a hydrophilic biomass material presents engineering problems in 3D printing. In this work, we show a new technology for making quality PLA-poplar hardwood filaments and their printing by fused deposition modeling (FDM) printing process. While a twin-screw extruder allows better mixing of fillers in plastics than a single-screw extruder, homogeneous biomass-filled PLA composites are difficult to produce even with a twin-screw extruder. However, with this technology, homogeneous filaments were made through a small and popular single-screw extruder and used for printing into shapes suitable for ASTM mechanical properties testing methods. Tensile, compression and impact testing, molecular weight, calorimetry, pycnometry, light and electron microscopy, infrared and NMR spectroscopy were carried out to characterize the composites. Overall, this work shows how biomass content, particle size, filament extrusion temperature and speed, and FDM parameters affect properties of 3D-printed materials made of PLA and wood.