Sustainable Additive Manufacturing: Mechanical Response of Acrylonitrile-Butadiene-Styrene over Multiple Recycling Processes

Abstract

Sustainability in additive manufacturing refers mainly to the recycling rate of polymers and composites used in fused filament fabrication (FFF), which nowadays are rapidly increasing in volume and value. Recycling of such materials is mostly a thermomechanical process that modifies their overall mechanical behavior. The present research work focuses on the acrylonitrile-butadiene-styrene (ABS) polymer, which is the second most popular material used in FFF-3D printing. In order to investigate the effect of the recycling courses on the mechanical response of the ABS polymer, an experimental simulation of the recycling process that isolates the thermomechanical treatment from other parameters (i.e., contamination, ageing, etc.) has been performed. To quantify the effect of repeated recycling processes on the mechanic response of the ABS polymer, a wide variety of mechanical tests were conducted on FFF-printed specimens. Regarding this, standard tensile, compression, flexion, impact and micro-hardness tests were performed per recycle repetition. The findings prove that the mechanical response of the recycled ABS polymer is generally improved over the recycling repetitions for a certain number of repetitions. An optimum overall mechanical behavior is found between the third and the fifth repetition, indicating a significant positive impact of the ABS polymer recycling, besides the environmental one.

Mechanical Properties of 3D-Printed Acrylonitrile–Butadiene–Styrene TiO2 and ATO Nanocomposites

“…An interesting finding that should be mentioned regarding the 3D printing manufacturing technology is that the mechanical properties of 3D printed ABS parts can differ, depending on the process parameters selected among other factors, in addition to the fact that FFF introduces anisotropy to the final parts [ 10 , 11 , 12 , 13 ]. Overall, the ABS polymer mechanical properties in 3D printing have been thoroughly reported in literature [ 10 , 14 , 15 , 16 , 17 , 18 ].…”

Towards Distributed Recycling with Additive Manufacturing of PET Flake Feedstocks

“…To better understand the material breakdown, a careful study of residence time vs. strength could be completed for future work. In addition, as with PLA [ 29 ], ABS [ 83 ], and HDPE [ 84 ], the impact of the number of recycle loops should be investigated and compared to a filament-extruding approach for multiple cycles. This is important to have a closed-loop supply chain in the circular economy [ 12 , 85 ].…”

Sustainable Additive Manufacturing: Mechanical Response of High-Density Polyethylene over Multiple Recycling Processes

“…Current research in the field seeks to optimize and improve the properties of recycled polymers and especially those of polyolefin [6][7][8][9][10][11][12]. Regarding the 3D printing of thermoplastics and recycled thermoplastics, there are several studies available that focus on the mechanical properties of fused filament fabrication (FFF) specimens [9,13,14], while the studies on recycled additive manufacturing materials in general are very limited [9]. Regarding the recycling of HDPE, this study presents a global recycling circular economy model ( Figure 1) with the four main parameters affecting the process of recycling.…”

“…All these parameters are crucial for the economy of the recycling process and the material's behavior after it is recycled. In literature, only a few studies are available on the mechanical properties of bulk and recycled HDPE [5][6][7][8][9][10][11] and HDPE composites [12][13][14][15][16][17][18], even less on the mechanical properties of HDPE 3D printed specimens [19], and no literature is available on the recycling of FFF HDPE specimens.…”