High-strength carbon fiber-reinforced polyether-ether-ketone composites with longer fiber retention length manufactured via screw extrusion-based 3D printing

The mechanical properties of 3D-printed carbon fiber-reinforced polymer composites play a pivotal role in engineering applications. However, the preparation of high-performance composites through material extrusion remains a great challenge. In this study, four fiber-reinforced polyether-ether-ketone (CF/PEEK) composites with varying fiber lengths were manufactured by a homemade screw extrusion 3D printer and evaluated for their application potential. A systematic exploration was conducted on the influence of fiber length and annealing on the mechanical performance of samples. The results demonstrated that increasing fiber length and annealing enhanced the tensile and flexural strengths of components while diminishing impact strength and ductility. With an average fiber retention length of 209 μm, the annealed parts displayed exceptional tensile and flexural strengths of 169.8 MPa and 223.3 MPa, respectively, marking a 143% and 88% improvement over unannealed pure PEEK. Longer fiber retention length, higher crystallinity, and fewer internal flaws contribute to the improved mechanical performance of the samples. This study provides a broader scope for the preparation and application of 3D-printed high-performance composites.