Toughness Enhancement of PLA-Based Filaments for Material Extrusion 3D Printing

Abstract

Poly(lactic acid) (PLA) is one of the most popular biodegradable thermoplastics in the market of 3D printing filaments used in the material extrusion (ME) technique. This is because it can be printed easily at low temperatures. However, its inherent brittleness limits its use in many applications. In this work, the toughness of PLA filament was improved by blending with various types of rubbers including natural rubber (NR), acrylic core–shell rubber (CSR), and thermoplastic polyurethane (TPU) in the amount of 15% by weight. PLA/TPU filament was found to have the smoothest surface with the best shape and dimension stability, while PLA/NR filament rendered the highest tensile toughness. In term of the effect of printing temperature, the highest printing temperature in this study (210°C) provided the highest smoothness with the best shape stability and dimension accuracy. Interestingly, the tensile toughness and elongation at break of 3D printed specimens were found to be higher than those of compression-molded specimens for all filament types. This could be explained by the ability of the 3D printing technique to produce specimens that aligned in the printing direction in a fiber-like pattern.