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Plastic waste is one of the major challenges of our times. With a global recycling rate of only 9 % and a continuous rise in plastic production, it is crucial to explore solutions to mitigate this problem. Mechanical recycling of plastic materials is one of the most accessible and widely used methods to recover thermoplastic polymers. In this study, a short-carbon-fiber-reinforced polyamide is mechanically recycled and recovered through Fused Granular Fabrication (FGF) 3D printing to print new parts. Chemical and mechanical analyses are conducted to investigate possible molecular alterations due to the recycling process, evaluating the effectiveness of the simplest recovery system. Additionally, FGF and Fused Filament Fabrication (FFF) are compared to assess any significant difference between the two technological solutions. Chemical analyses show no substantial difference in the chemical and physical properties of pristine and recycled material. However, micro-CT scans and tensile tests show notable differences between FGF and FFF technologies in microstructure and mechanical properties. Recycled specimens result 24 % and 6 % denser than FFF and FGF pristine respectively (having the same volume). This results in a maximum increase in stiffness (up to 43 %) and ultimate strength (up to 20 %) for recycled dogbone specimens. Besides minor microstructural aspects, no relevant differences are found between pristine and recycled material printed using FGF. A case study on sandwich cores is presented showing the feasibility of the recycling process. Due to its higher density, the recycled core performs 26 % lower in energy absorption when compared to pristine ones at the same weight. • Short carbon fiber reinforced PA12 is recycled through fused granular fabrication. • Physicochemical analyses show no substantial differences of the recycled material. • Mechanical properties are comparable between recycled and pristine material. • A structural case study is proposed with a 3D-printed recycled core structure.
Bandinelli et al. (Fri,) studied this question.