The properties of 3D printed poly (lactic acid) (PLA)/poly (butylene-adipate-terephthalate) (PBAT) blend and oil palm empty fruit bunch (EFB) reinforced PLA/PBAT composites used in fused deposition modelling (FDM) 3D printing

Poly (lactic acid) (PLA) is amongst the preferable materials used in 3D printing (3DP), especially in fused deposition modelling (FDM) technique because of its unique properties such as good appearance, higher transparency, less toxicity, and low thermal expansion that help reduce the internal stresses caused during cooling. However, PLA is brittle and has low toughness and thermal resistance that affect its printability and restricts its industrial applications. Therefore, PLA was blended with various content of polybutylene adipate terephthalate (PBAT) at 20, 50 and 80 wt% via twin-screw extruder to improve the ductility and impact properties of PLA. The addition of PBAT increased the elongation at break of PLA with a linear increasing amount of PBAT. However, 20 wt% PBAT was selected as the most promising and balance properties of PLA/PBAT because although it has a slight increment in its elongation at break but it exhibits higher impact strength than that of PLA. The tensile strength and tensile modulus of sample with 20 wt% PBAT is greater than 50 and 80 wt% PBAT. Then, PLA/PBAT (80/20, 50/50 and 20/80) and PLA/PBAT/EFB (80/20/10) were printed using FDM machine and were characterized in tensile, impact and morphological properties. The tensile result indicated that the addition of PBAT decreased the tensile strength and tensile modulus of PLA/PBAT-3DP. The terephthalate group in the PBAT affects the mechanical properties of PLA/PBAT-3DP, resulting in high elongation at break but relatively low tensile strength. Besides, the tensile strength and tensile modulus of PLA/PBAT/EFB-3DP decreased and lower than PLA-3DP and PLA/PBAT-3DP. The impact test resulted in high impact strength in PLA/PBAT-3DP, where 50/50-3DP and 20/80-3DP are unbreakable. The impact strength of PLA/PBAT/EFB-3DP is also increased from PLA-3DP but lower than PLA/PBAT-3DP. The scanning electron microscopy (SEM) results revealed that the filament layering on 80/20-3DP was oriented than 50/50-3DP and 20/80-3DP. Besides, the SEM images of PLA/PBAT/EFB-3DP revealed the inhomogeneous and large agglomeration of EFB particle in PLA/PBAT matrix. Therefore, in the future, the polymer blend and polymer blend composite from PLA, PBAT and EFB can be developed where the properties will be based on the study and this study also shed light on the importance of extrusion settings during the manufacture of filament for 3D printing.