EVALUATING THE CLOSED-LOOP RECYCLABILITY OF FDM 3D PRINTING PLASTIC WASTE

3D printing is an additive manufacturing technique that allows the fabrication of complex structures and geometries from a three-dimensional digital model. Recent developments have reduced the cost of 3D printers, making them affordable and, as a result, expanding their applications in different industries. On the other hand, the popularization of this technology also accompanied an increase in the deposition of polymeric residues. This work aimed to investigate the closed-loop recyclability potential of waste generated by fused deposition modeling (FDM) printing by evaluating the plastics' degradation in each life cycle. Discarded ABS and PLA print parts were milled and extruded into filaments. Specimens were printed using commercial and recycled filament. The materials were characterized by their chemical, thermal and rheological properties. The transition temperatures obtained by DSC indicated that the processing parameters adopted in extrusion and printing were adequate. The recycled material exhibited lower thermal stability, increased melt flow index, and a higher degree of crystallinity (for PLA). Finally, it was found that the recycling process (extrusion and printing reprocess) of PLA and ABS caused oxidative thermo-mechanical degradation resulting in the loss of physicochemical properties that can affect mechanical performance. Thus, it was found that recycled filaments are adequate to print models that will not be subject to high demands.