3D printing of lightweight "All-Polyethylene Single Component" composite materials designed for circularity

All-hydrocarbon composites ("all-HC") are ideal sustainable materials for lightweight construction: since the matrix and the reinforcing component of the composite are made of the same polymer, the composite can be recycled easily. All-HC are blends of a low (PE-wax), middle (HDPE) and high molecular weight (UHMWPE) fraction of polyethylene. The UHMWPE-fraction forms reinforcing nano-fibrils when subjected to extensional flow during injection molding or extrusion-based 3D printing. Aim of the study is to provide a mechanical (strength, fatigue, creep) and tribological (friction and wear) characterization of 3D-printed all-HC specimens. Tensile strength, fatigue strength, creep resistance and tribological behavior was studied on 3D-printed specimens. Compared to the HDPE-reference, 3D-printed all-HC specimens showed a significantly higher tensile strength and modulus and a significantly improved fatigue and creep performance. In contrast, no substantial increase in wear resistance of the all-HC pins could be observed.