Preparation and Microstructural Characterization of High‐Strength <scp>PEKK</scp> (Polyether Ketone Ketone)‐Based Ternary Composites for <scp>FDM</scp> Fabrication

ABSTRACT High strength Polyether ketone ketone (PEKK) composites and its complex structures made by Fused Deposition Modeling (FDM) exhibit wide application in aerospace and medical fields. However, FDM of PEKK‐carbon fiber (CF) composites is hampered by poor interfacial compatibility and weak adhesion between PEKK and CF. This severely degrades the mechanical properties and printability of composite filaments, thus impeding their widespread application. To tackle this crucial scientific problem, this study devises a novel strategy by constructing a ternary composite system consisting of CF, trisilanolphenyl‐polyhedral oligomeric silsesquioxane (POSS), and PEKK. Specifically, benzene derivatives derived from POSS pyrolysis are deliberately introduced to form conjugate interactions with PEKK molecular chains, thereby strengthening the interfacial bond between CF and the PEKK matrix. This innovative approach not only improves interfacial compatibility but also significantly enhances the mechanical properties of the composite. Employing the FDM process, we successfully fabricated high‐precision components with intricate geometries. Comprehensive mechanical assessments revealed that the CF/POSS/PEKK ternary composite exhibits a 33% increase in tensile strength and a 27% improvement in interlayer bonding strength compared to pure PEKK. Moreover, the printed components achieved excellent dimensional accuracy and surface quality, fully meeting the strict requirements of aerospace applications. This study not only offers a groundbreaking method for developing high‐performance PEKK‐based composite filaments but also establishes a solid theoretical and experimental foundation for their broader use in FDM‐based additive manufacturing.