Development and Preliminary Analysis of 3D Printing Filament from Post-consumer Polypropylene

In the past few years, many researchers have focused on using recycled or post-consumer materials in three-dimensional (3D) printing, which leads to better plastic waste management and sustainable practices. This study focuses on the fabrication of post-consumer polypropylene (rPP) filaments for use in the most common 3D printing method, fused filament fabrication (FFF). The rPP filaments were prepared by blending injection-grade rPP (i-rPP) and extrusion-grade rPP (e-rPP) at various ratios. The effect of different rPP grade ratios on filament diameter consistency, filament ovality, and melt flow index (MFI) was measured. The various ratios of i-rPP to e-rPP, such as 100:0, 40:60, 50:50, 60:40, and 0:100, were prepared. The 50:50 ratio was found as the starting point for achieving a consistent filament diameter. The MFI results showed that the MFI decreases when more e-rPP is incorporated in the blend. The tensile properties of 3D printed 50:50 rPP blend are also measured and compared with commercial PP. Overall, this research exhibits the potential of upcycling PP waste materials into functional filaments for sustainable 3D printing applications.