Technical Evaluation of Mechanical Recycling of PLA 3D Printing Wastes

3D printing is a manufacturing technique that is gaining a fair amount of interest in recent years. This interest has increased, even more, during the worldwide COVID-19 pandemic, since 3D printing allowed to mitigate the shortage of Personal Protective Equipments (PPEs) in the fight against the COVID-19 [1,2]. Numerous initiatives, such as coronamakers in Spain, have produced large amounts of face shields by 3D printing. However, this large production of medical supplies does not come without problems, including the large amount of waste generated from defective pieces and scraps. Consequently, it is important to propose methods to manage those wastes and increase the sustainability of the process [3]. Closed-loop recycling could be an interesting alternative, although it leads to the degradation of the polymer, as it has been reported for PLA, one of the most used materials in 3D printing [4].

The main objective of this work is the evaluation, from a material properties point of view, of the feasibility of the mechanical recycling of 3D printing PLA wastes. To do this, two types of PLA wastes were mechanically recycled and studied: (i) a pure and well-known grade, and (ii) a blend of several grades coming from different coronamakers agents. The results suggest that recycled PLA could be used in several applications, since good mechanical and thermal properties were achieved. Nevertheless, special attention to the composition of the wastes must be paid, since it could affect important parameters such as intrinsic viscosity and crystallization behavior.

References

[1] Choong Y.Y.C., et al., Nat Rev Mater 5 (2020), DOI: 10.1038/s41578-020-00234-3

[2] Zhao et al., J Clean Prod 197 (2018), DOI: 10.1016/j.jclepro.2018.06.275

[3] Campana G., et al. (eds) Smart Innovation, Systems and Technologies 68 (2017), DOI: 10.1007/978-3-319-57078-5_73

[4] Beltrán F.R., et al., J Environ Manage 216 (2018), DOI: 10.1016/j.jenvman.2017.05.020