Experimental Analysis of Crystallinity and Mechanical Properties for Fused Filament Printed Polyetherketone Composites

The objective of this article is to examine the impacts of molybdenum disulphide (MoS2) and graphite-filled (Gr) polyetheretherketone (PEEK) composites that have been fabricated through 3D printing on their mechanical properties and crystallinity. Seven samples and thirty-five dog bones were produced using different filament strands to conduct the analysis. Before extrusion into filaments, the solid lubricants, MoS2, and graphite were uniformly dispersed within the PEEK through mechanical blending. At a concentration of 10 wt.%, the PEEK/MoS2 composites exhibited the highest tensile strength, measuring approximately 104 MPa, while the PEEK/Gr composites displayed the lowest tensile strength at the same concentration, approximately 36 MPa. In addition, the PEEK/MoS2 composites demonstrated better elongation, approximately 4.7%, compared to the PEEK/Gr composites, which exhibited approximately 2.3% elongation. X-ray diffraction (XRD) data revealed that neither MoS2 nor graphite significantly interacted with the PEEK matrix. The degree of crystallinity, as determined by density matrices, indicated that the printed PEEK composites possessed a higher level of crystallinity, approximately 62% at a concentration of 5 wt.%, than the calculated values. This suggests that the filament-making and 3D printing processes had an annealing effect. The significance of solid lubricant content and dispersion in shaping the mechanical properties and crystal formation of 3D-printed PEEK composites is emphasized in this study. Furthermore, this research provides valuable insights for optimizing PEEK-based materials for various applications.