Electromagnetic Interference Shielding Effectiveness of 3D ‐Printed Multi‐Walled Carbon Nanotubes/Rice Husk Charcoal/Polylactic Acid Composites

ABSTRACT The dispersion state of carbon nanomaterials in polylactic acid (PLA) matrix is a key factor affecting the comprehensive performance of composites. Poor dispersion often leads to composites having inadequate mechanical properties and insufficient electromagnetic interference (EMI) shielding effectiveness (SE). To address this issue, this study employs silane‐coupled rice husk charcoal (RHC) as a dispersant for multi‐walled carbon nanotubes (MWCNTs), combining the significant electromagnetic and mechanical properties of MWCNTs with the excellent processability of PLA. MWCNT/RHC/PLA composites were prepared using 3D printing technology, and their microscopic morphology (SEM), thermal decomposition behavior (characterized by TGA), crystallization properties (XRD and DSC), mechanical properties, and EMI SE were comprehensively analyzed. The results indicated that the addition of MWCNTs formed a clear conductive network within the composite materials and notably improved their crystallization ability. With a MWCNTs content of 9 wt%, the composite material displayed excellent mechanical properties and EMI SE, with a tensile strength of 66.21 MPa and EMI SE of 22.57 dB, and its main mechanism of shielding EMI is reflection. The materials produced in this study demonstrate the potential of PLA‐based composites as high‐performance, environmentally friendly EMI shielding materials.