Carbon Nanotube‐Reinforced Continuous Carbon Fiber Reinforced Polycarbonate Prepreg Filament Based on the Suspension Impregnation Process and 3D Printing

ABSTRACT Continuous carbon fiber reinforced polycarbonate (CCF/PC) prepreg filaments hold broad prospects in additive manufacturing; however, they still face challenges such as limited thermal properties, low matrix strength, and weak interlaminar interfacial adhesion after 3D printing. This study proposes a synergistic reinforcement strategy, specifically, by introducing carboxylated multi‐walled carbon nanotubes (MWCNT‐COOH) into a polycarbonate (PC) suspension, polycarbonate/carbon nanotube (PC/CNT) suspensions are prepared, and high‐performance CCF/PC‐CNT prepreg filaments suitable for fused deposition modeling (FDM) are prepared using solution impregnation‐thermal traction technology. That not only improves the heat resistance but also enhances the matrix strength and the 3D‐printed interfacial properties. The results indicate that when the CNT content is 1.5 wt%, the glass transition temperature (T g ) of the PC/CNT increases by approximately 5°C, and the heat resistance and wettability of the PC resin are improved. Furthermore, the tensile strength of the prepreg reaches 1655 MPa, representing a 16% increase compared to the neat PC group. After 3D printing, the interlaminar shear strength (ILSS) of the specimens increases by 34% compared to the control, reaching 45 MPa. Correspondingly, the fracture mechanism transforms from typical interfacial debonding to cohesive matrix failure with higher energy dissipation, indicating that the interfacial properties are improved.