Enhanced microwave absorption through fused deposition modeling of CNT/PLA/TPU composites

Electromagnetic pollution has become a major issue in modern society; the design and development of materials for wave absorption hold significant importance in the domain of electromagnetic wave shielding and protection. In this research, a dual-stage procedure consisting of mechanical milling followed by thermal extrusion was used to prepare carbon nanotube (CNT)/polylactic acid (PLA)/thermoplastic polyurethane (TPU) composite filaments. The composites of CNT/PLA/TPU were successfully fabricated through fused deposition modeling techniques. The study systematically explored the impact of CNT analysis on the mechanical properties, electromagnetic parameters, and composites’ performance in wave absorption. The findings reveal that the PLA/TPU-based composites demonstrate excellent mechanical characteristics, including a tensile strength of 24 MPa and an elongation at break of 19%. When the CNT content was 4 wt. %, the composites achieved Rlmin of −31.21 dB and an effective absorption bandwidth (EAB) of 5.52 GHz at a 2.0 mm thickness. Compared with existing studies, this research highlights the potential to achieve excellent mechanical and wave-absorbing properties at low CNT content. The wave attenuation capability of the composites is significantly enhanced by the collaborative interaction of multiple reflections, conductive loss, dipole polarization, and interfacial polarization. The results not only provide novel perspectives into the design of efficient wave-absorbing materials but also lay the foundation for the development of materials in the area of electromagnetic pollution protection.