Abstract
The melt-impregnation–pultrusion route is commonly applied to produce composite prepreg filaments, yet the resulting materials often show uneven fiber distribution, reduced tensile strength, noticeable porosity, and constrained thermal stability. Here, we develop an integrated platform for producing continuous carbon fiber/polyether ether ketone (CCF/PEEK) prepreg filaments that combines melt impregnation with closed-loop haul-off. By arranging staggered upper–lower guide rollers inside the impregnation chamber and coupling an air-jet tow-spreading unit, the design promotes efficient fiber dispersion and thorough resin wet-out, while a custom sizing die ensures dimensional stability. Parametric analysis of drawing speed and melt temperature shows that at 400 °C and 6 mm/s, more complete fiber wetting and lower porosity are achieved, yielding a filament tensile strength of 1559.71 MPa. Micro-CT together with optical scanning electron microscopy (SEM) characterization further confirms markedly improved fiber distribution in the matrix, with the minimum porosity reduced to 0.47%. Differential scanning calorimetry/ Thermogravimetric analysis (DSC/TGA) tests indicate more complete crystallization and superior thermal stability near 400 °C, whereas signs of thermo-oxidation and shrinkage mismatch emerge at 420 °C. Finally, tensile coupons three-dimensional (3D) printed by fused deposition modeling (FDM) with the developed filaments achieved a peak strength of 862.52 MPa, indicating that the material–process route can effectively support high-performance CCF/PEEK additive manufacturing for aerospace, transportation, and other advanced applications.