3D‐Printing Preparation and Multi‐Functional of CNT‐Filled PP/SCF Composites

ABSTRACT Fused deposition modeling (FDM) 3D‐printing technology is widely used because of its low equipment cost and flexible processing capabilities. However, the polypropylene (PP) matrix has disadvantages such as printing warpage and limited functionality. Although short carbon fiber (SCF) can improve the printability of PP, a single carbon filler is difficult to balance mechanical and multi‐functional performance, and excessive filling easily causes interfacial defects. In this study, a cross‐scale synergistic strategy of SCF (30 wt%) and carbon nanotubes (CNT) was proposed. The PP/SCF/CNT composites were prepared by blending extrusion and the FDM process, and the regulatory rules of CNT content (0, 5, 10, 15, and 20 wt%) on material multi‐functionality were systematically explored. The results show that CNT acts as a physical cross‐linking network point in the PP matrix and collaborates with SCF to optimize the conducting pathway. When the CNT content is 5 wt%, the flexural strength reaches 46.38 MPa, which is 35.57% higher than that of pure PP/SCF. As the CNT content increases to 20 wt%, the thermal conductivity of the composite increases to 0.44 W/(m·K), its resistivity decreases to 30 Ω, and the electromagnetic shielding effectiveness reaches 22.72 dB. The breakthrough overcomes the limitations of traditional filler content and single functionality. Through multi‐component synergistic design, this study achieved the integration of mechanical and functional properties of 3D‐printed composites, providing new ideas for the manufacturing of high‐performance devices in the fields of electromagnetic shielding, thermal management, and intelligent sensing.