Sustainability driven additive manufacturing: repetitive mechanical recycling response evaluation to valorize polycarbonate scrap†

Abstract

Polycarbonate (PC) is a widely used thermoplastic. Therefore, the amount of waste produced is notable. The exploitation of such waste is of great interest nowadays in the industry and academic society, due to its contribution to environmental pollution and other negative consequences. Herein, the possibility of using PC scrap as a raw material in 3D printing (material extrusion – MEX) is reported. The efficacy of the PC polymer after six thermomechanical courses was evaluated. The effect on rheology, mechanical performance, and thermal behavior is reported. The morphological characteristics were also assessed through scanning electron microscopy, while two quality metrics, i.e., geometrical accuracy and 3D printing structure porosity of the parts, were investigated through micro-computed tomography. The findings were correlated to report the impact of thermomechanical processing on the PC polymer properties. A 9% tensile strength increase compared to the virgin polymer is reported (third round), while the flexural strength was improved by 14% (second round). Then the strength declined. It was lower than that of the virgin material on the sixth thermomechanical repetition. The findings showed that the life of PC can be extended through thermomechanical recycling for 3D printing applications.