Study on FDM preparation and properties of carbon black/ nickel/ polylactic acid/ thermoplastic polyurethane electromagnetic wave absorbing composites

Developing microwave-absorbing materials characterized by "broadband, lightweight, thin thickness, and strength" poses a formidable challenge within the realm of electromagnetic wave absorption. The optimal absorbent should exhibit exemplary dielectric and magnetic loss characteristics. This study utilized polylactic acid (PLA) and thermoplastic polyurethane (TPU) as the matrix and carbon black (CB) and nickel (Ni) as the absorbers, employing Fused Deposition Modelling (FDM) technology to fabricate CB/Ni/PLA/TPU composite electromagnetic wave absorbing materials. When the CB content is 5 %, the strongest absorption reaches −34.14 dB (2 mm), and it exhibits an effective absorption bandwidth spanning 5.92 GHz (12.08–18 GHz). Concurrently, the corresponding material exhibited certain mechanical properties, including flexural strength, compressive strength, and tensile strength reaching 6.38 MPa, 27.48 MPa, and 18.26 MPa, respectively. Additionally, the tensile elongation at break was 5.1 %. The electromagnetic wave absorption mechanism reveals that the outstanding absorbing property is mainly due to the synergy of carbon/magnetic materials. This is mainly contributed to by the following aspects: conduction losses induced by CB, polarization losses due to internal defects in the material, interface polarization and multiple reflections of electromagnetic waves resulting from the numerous interfaces, magnetic losses generated by Ni, and more importantly, the excellent impedance matching achieved by the carbon/magnetic synergy. The work has developed carbon/magnetic composite materials that exhibit outstanding absorption performance and possess certain mechanical capabilities, enabling the development of effective electromagnetic wave absorber architectures.