Multiple Reprocessing of Conductive PLA 3D-Printing Filament: Rheology, Morphology, Thermal and Electrochemical Properties Assessment

Abstract

Additive manufacturing technologies are gaining more and more attention, resulting in the development or modification of 3D printing techniques and dedicated materials. On the other hand, economic and ecological aspects force the industry to develop material recycling strategies. In this work, the multiple reprocessing of a commercially available PLA conductive composite with carbon black filler, dedicated to 3D printing, was investigated. The effects of extrusion temperature (190 °C and 200 °C) and reprocessing steps (1–5 steps) on the rheology, morphology, thermal and electrochemical properties of the conductive PLA 3D-printing filament were evaluated. The results showed deterioration of the thermal stability and material strength, as well as the influence of reprocessing on the melting point, which increases after initial melting. The electronic conduction mechanism of the composite depends on the percolation paths and it is also affected by the multiple processing. The reversibility of the [Fe(CN)6]3−/4− redox process diminishes with a higher degradation level of the conductive PLA. Importantly, the material fluidity was too high after the multiple reprocessing, which should be considered and suitably corrected during CB–PLA application as a 3D-printed electrode material.

Tailoring diamondised nanocarbon-loaded poly(lactic acid) composites for highly electroactive surfaces: extrusion and characterisation of filaments for improved 3D-printed surfaces

“…Electrode evaluation was carried out using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). First, the electrochemical activation procedure has to be carried out in 1M NaOH, using the methodology stated elsewhere [ 12 , 48 ]. See the SI file, section S2 for more details.…”

“…Uniform distribution of conductive paths is key to obtaining electrically homogeneous electrode surfaces and avoiding the effect of partially blocked electrode areas [ 11 ]. One should note that the thermal stability of the filament under reprocessing is another concern, which might decrease the electrochemical performance by nanofiller agglomeration and so a decrease in the number of conductive paths [ 12 ]. Notably, while conductivity enhancement is similar and depends on the formation of conductive paths within the material, the electrochemical response of these composites differs significantly [ 13 , 14 ].…”

Novel advancements in additive manufacturing of PLA: A review

“…Meanwhile, PNCs have been fabricated with enhanced thermal and electrical conductivity, improved mechanical and thermal expansion, and increased fire retardancy for automotive, oil and gas, and other versatile applications 137–207 . Finally, it is emphasized that 3‐DPT and 4‐DPT are innovative processing technologies, presenting the future route of the manufacturing sector 208–244 …”

Investigation of Tensile Properties of FDM-Printed Reclaimed Carbon Fiber Reinforced Reclaimed Polyamide-6 Composites (rCF/rPA) via Various Densities of Infill Patterns

“…FDM is also an eco-friendly approach featuring in-house recycling [3]. For example, the support structures and process failure (e.g., model wrapping and cracking) of FDM-printed products can be directly reclaimed into close-looped filaments for secondary printing with sustainable development [4]. Moreover, because of ease of operation, recycling via FDM provides incomparable advantages compared with traditional recycling of composite wastes, such as laminate, compression molding, hot press, injection molding, etc.…”