Controlled conductive networks in 3D‐printed TPU/CNTs composites for enhanced EMI shielding

Abstract Constructing effective conductive networks within polymer composites has proven to be a successful strategy for fabricating electromagnetic interference (EMI) shielding materials. Herein, we present a novel approach for creating high‐temperature EMI shielding materials by integrating 3D printing with compression molding. First, a thermoplastic polyurethane (TPU) framework was printed using fused deposition modeling (FDM), enabling customization of the composite's conductivity. This framework was subsequently treated with solution immersion to load carbon nanotubes (CNTs) onto the TPU surface, followed by compression molding to form TPU/CNTs composites with a segregated conductive network. The effects of coating cycles and hot‐pressing temperature on the conductive network and EMI shielding performance were systematically studied. The results revealed that hot pressing temperature significantly influences the development of the conductive network. At 130°C, a weak conductive network was formed due to spatial confinement within the TPU frame, yielding an EMI shielding effectiveness (SE T ) of 44 dB. However, at 190°C, a more extensive conductive network was developed as the CNTs‐rich phase overcomes spatial constrains, achieving an impressive SE T of 52 dB. This high‐performance material, coupled with its simple and versatile fabrication process, holds promise for the development of advanced EMI shielding materials. Highlights Integrating 3D printing and compression molding, segregated conductive networks was established in TPU/CNTs composites, achieving up to 52 dB X‐band EMI SE. Hot‐pressing temperature plays a critical role in constructing effective networks. A weak conductive network formed at 130°C due to spatial confinement, resulting in a lower SE T value. At 190°C, CNTs‐rich phase formed a robust conductive network, yielding a SE T of 52 dB. TPU/CNTs composites demonstrates excellent electrical properties with a low R of 0.22, enabling next‐gen EMI shielding for high‐performance applications.