Recycling of Polylactic Acid 3D Printing Residues: Potential Use as a Matrix in Nanocomposites

With the growth of the 3D printing industry, there are concerns regarding the PLA residues from the manufacturer and the temporary use of the material. To address these concerns, this work presented a sustainable approach to recycling polylactic acid (PLA) residues from 3D printing by incorporating graphene as a reinforcement material. Aiming to simulate a mixed material scenario, the residue is generated by processing on a Creality Ender 3 printer, heated to 200 °C at a speed of 25 mm/s. Then, PLA residues were ground and mixed using a co-rotating twin-screw extruder at 190 ºC with 0.18% by weight of graphene. In general, graphene was incorporated, resulting in a homogeneous distribution that does not contribute to increasing the tensile strength compared to recycled PLA; however, it is higher than that of the original PLA filament. Regarding the thermal properties, the reprocessed material retains its original thermal stability, with a slight decrease in the degradation temperature. The recycled PLA exhibited a crystallinity of 20.3%, which was higher than that of the original PLA filaments and recycled PLA with graphene (3.4%). In conclusion, PLA residues from 3D printing can be recycled to obtain PLA nanocomposites without compromising the mechanical and thermal properties.