Recycling polypropylene from non-woven disposable masks in developing a three-dimensional printing filament

Abstract

Non-woven disposable masks play a unique role in reducing the COVID-19 pandemic threat in transmission between people, but the huge amount of disposable non-woven masks generated every day are currently posing a serious challenge to our environment on a global-wide scale. In line with this emerging problem, a series of recycling processes were designed and conducted to evaluate the performance of material recovered from those waste masks for potential use in three-dimensional (3D) printing. A composite filament from recycled polypropylene (rPP) and an additive material, glass fiber (GF), was fabricated by melt-blending processing followed by single-screw extrusion. A variety of material properties, including the chemical/mechanical/microstructure property, thermal stability, printability, rheology performance, and geometrical accuracy toward GF/rPP composite filaments, were comprehensively analyzed. Our results demonstrated that two important mechanical properties, the compression strength and the tensile strength, to a 3D printed object by fused deposition modeling (FDM) from the GF/rPP composite were significantly higher than that of a FDM 3D printed object from GF/polypropylene composites. The specific warpage parameter (Wsp) and the surface roughness (Sa) for a 3D printed object from the GF/rPP composite at 30 wt% GF additive would have printing accuracy of 0.54% ± 0.0014 and 21.1 ± 0.76 µm, respectively, and no clogging phenomenon was observed in the printer nozzle channel during the printing processing, suggested that this recycling method for a large number of non-woven waste masks was potentially applicable in serving as a FDM 3D printing material.