Synergism between lignin, functionalized carbon nanotubes and Fe3O4 nanoparticles for electromagnetic shielding effectiveness of tough lignin-based polyurethane

In this work, a kind of novel flexible lignin-based electromagnetic shielding polyurethane (FeCLPU) with excellent properties was prepared and studied. Lignin was applied as an reinforcement with modified carbon nanotubes (CNT) and aminated ferroferric oxide nanoparticles (Fe3O4) in polyurethane to improve electromagnetic shielding properties. The KH550-modified Fe3O4 was mixed with lignin, polyethylene glycol (PEG), hexamethylene diisocyanate (HDI) and modifiedCNT to in situ synthesize FeCLPU. When the concentrations of both Fe3O4 and CNT were 10% and the lignin content was 15%, the maximum EMI SE reached 37.5 dB. This excellent electromagnetic shielding effectiveness was attributed to the synergistic effects between the Fe3O4, CNT and lignin. The tensile strength attained 7.25 MPa. Thus, the FeCLPU with uniformly dopped Fe3O4 and CNT was expected to be promising in a wide array of applications in civilian fields, due to its excellent overall performance, low cost and eco-friendliness.