Performance of 3D printed poly(lactic acid)/halloysite nanocomposites

Abstract The study exploited two approaches for enhancing the mechanical properties of poly(lactic acid) (PLA) fused deposition modelling (FDM) printed parts. The first method was ‘fill compositing’ where PLA FDM parts were printed at 5%, 10%, 20% and 100% infills and then 5% and 10% infill specimens were injected with epoxy/halloysite nanotube (HNT) solution. The second method involved incorporating HNT within the PLA matrix by melt compounding method to fabricate PLA/HNT nanocomposite filaments. A bench-top filament extruder was used to produce PLA/HNT nanocomposite filaments and these extruded filaments were then used to print specimens for mechanical characterization. It was evident that the impact resilience increased for nanocomposites produced by both methods. For instance, printed samples with 5% infill injected with epoxy/HNT outperformed the rest of the specimens by 55%, followed by composites printed using fabricated PLA/HNT filaments. Fracture surface of the specimens was observed and analyzed using images from a Scanning Electron Microscope (SEM) to understand the underlining fracture mechanisms. The results of this study showed how a smart filament can be made using a house made extruder as well as how adding nanofillers can contribute to the mechanical strength, processability and printability of a 3D printed specimen. Moreover injecting thermoset polymers reinforced with halloysite nanotubes can fill porosities and reinforce the physical properties of the 3D samples which were printed at lower resolutions.