Improving the mechanical properties of 3D printed recycled polypropylene‐based composites through adjusting printing temperature

Abstract This work aimed at investigating the effects of recycling on the mechanical properties of recycled polypropylene (PP)‐based composites and improving the mechanical properties of recycled materials by adjusting the remanufacturing temperature. In this study, 3D printing was selected as the remanufacturing approach and the composites were ground and reextruded up to nine times to simulate mechanical recycling. The gel permeation chromatography results indicated that the recycling led to a reduction in molecular weight, increasing the melt fluidity of the materials. Excessive melt flow of material during printing caused the poor quality of printed parts with macro and micro defects, deteriorating the mechanical properties of the printed specimens. To improve the final quality and mechanical properties of the printed specimens, melt flow during the printing of recycled materials was adjusted by tuning the printing temperature. The results found that the mechanical properties of the recycled PP‐based composites were well enhanced by using tuned printing temperature.