Title : A PEEK into fractures: Enhanced mechanical properties of CF/PEEK composites with aramid pulp interleaves for orthopaedic applications
Abstract:
In recent years, carbon fiber-reinforced PolyEtherEtherKetone (CF/PEEK) implants have seen increased use in orthopaedic applications due to their exceptional biomedical properties. However, an increase in reported cases of laminar CF/PEEK implant failures has raised concerns, with delamination being a primary mechanical failure mode. Delamination, which can lead to damage and crack propagation in implants, may be triggered by low-energy impacts, such as patient falls. Even minor damage can significantly reduce the composite strength, and in severe cases, lead to implant failure. Such implant failures result from the lack of fiber reinforcement to effectively transfer load perpendicular to the carbon fiber plies. To address this, micro- and nano-sized aramid pulp (AP) fibers, known for their excellent impact resistance and high tensile strength, are incorporated into the composite microstructure. Interleaved AP fibers are introduced between the carbon fiber plies to promote fiber bridging and load transfer between layers, thereby enhancing the delamination toughness of CF/PEEK composites. In this study, CF/PEEK composites toughened with AP interleaves were manufactured and mechanically tested. The findings reveal that AP-toughened CF/PEEK composites exhibit a 51% increase in damage tolerance under impact loading, along with a 41% improvement in compressive strength and a 19% increase in flexural-after-impact (FAI) strength. This study demonstrates the feasibility of incorporating commercially available, low-cost AP fibers into the implant manufacturing process to produce damage-tolerant and high-performance CF/PEEK implants, enhancing patient healing outcomes.
