Superior strength in the 3D‐printed polyether‐ether‐ketone composites reinforced by annealing and carbon fibers

Abstract

AbstractThe light‐weight, high‐strength polyether‐ether‐ketone (PEEK) shows great potential for weight‐sensitive, load‐bearing applications. The adoption of PEEK in those applications has been accelerated by the recently emerged three‐dimensional printing (3D‐printing) technique. However, achieving high strength in the 3D‐printed PEEK is still challenging. In this study, the mechanical strength of the 3D‐printed PEEK is jointly reinforced with high‐loading carbon fibers (CFs) and annealing treatment. The PEEK‐CF composite filaments containing three different CF contents, ranging between 5 and 15 wt%, are first prepared in‐house and subsequently printed into specimens. Both the tensile and flexural tests show that the composite containing 10 wt% CF exhibits the highest strength, reaching 114.7 and 139.2 MPa, respectively, the tensile strength of which amounts to a 35% increase from the unfilled counterpart. The annealing treatment on the printed samples further increases the strength of the composite both at room temperature and high‐temperature. After annealing, the tensile strength of the 3D‐printed PEEK‐CF composite reaches 131.5 MPa at room temperature and over 60 MPa at 200°C. The results from this study can spur new insights into design advanced polymer composites with outstanding mechanical properties.Highlights Custom‐made PEEK‐CF composite filaments with high CF content, up to 15 wt% 3D‐printed PEEK‐CF composites exhibit very high tensile strength, reaching 115 MPa. The annealing treatment further strengthens the printed composite, up to 131 MPa. The jointly strengthened PEEK‐CF composite remains strong at elevated temperatures.