Lifting the quality of fused filament fabrication of polylactic acid based composites. (1st April 2021) - Wang, Sisi
Abstract: The development of well-designed polylactic acid (PLA) based composite filaments through fused filament fabrication (FFF) is crucial, as PLA printed parts are characterized by a high brittleness. Here we focus on FFF composite formation using ductile poly (butylene adipate-co-terephthalate) (PBAT), the nanoclay cloisite and the chain extender Joncryl. A high modulus, flexibility, toughness and notched impact strength result upon combining PLA/PBAT (80:20; mass basis) with a sufficiently high cloisite amount (1–5 phr) supported by a suited Joncryl amount (0.3 phr). A fine PBAT dispersion is then ensured, as confirmed by scanning and transmission electron microscopy. For high cloisite amounts ( e.g. 10 phr) the crystallinity and vicat softening temperature enhance but cloisite aggregation is unavoidable, leading to a strong reduction in tensile strain and toughness. Annealing increases crystallinity thus material strength, rigidity and impact, at least partially overruling the need of a fine dispersion. Novel radar charts are also reported to select an optimal bio-based blend suitable for different end-user applications by adjusting the composition and possible post-annealing of printed products. Graphical abstract: Image 1 Innovative bio-based fused filament fabrication (FFF) of composite PLA-based filaments. Highlights: Design of PLA-based composite filaments for high quality FFF. Morphology control for both PLA matrix and PBAT dispersed phase. Introduction of radar charts for composite filaments in view a desired application