Enhanced impregnation behavior and interfacial bonding in CF/PEEK prepreg filaments for 3D printing application

The high specific strength and modulus of carbon fiber-reinforced poly-ether-ether-ketone composites (CF/PEEK) have made them particularly useful for structural applications. However, undesired defects are derived from the incompatibility between the thermoplastic matrix and the thermoset-based sizing agent at the CF/PEEK interface. This issue is further aggravated by three-dimensional (3D) printing fabrication for incomplete impregnation during the printing process. Herein, we introduce a thermoplastic-based sizing treatment into CF/PEEK prepreg filament preparation in order to reduce or eliminate the defects from the material and process sources of (3D) printing. We evaluate the influence of the sizing treatment on the impregnation and compatibility behavior of the CF/PEEK prepreg filaments. In comparison to the unsized CF/PEEK composites, the tensile strength of the polyether imide- and PEEK-sized CF composites increased by 47.6% and 54.0%, respectively. In combination with the thermoplastic-based sizing treatment and prepreg filament approach, 3D printing has the potential to create structural parts with favorable interfacial bonding.