Nanocomposite based on epoxy and MWCNTs modified with NiFe2O4 nanoparticles as efficient microwave absorbing material

In order to make a microwave absorbent material with good dielectric and magnetic properties, well dispersed microwave absorbing hybrid epoxy polymer composites containing nickel doped Fe3O4 nanocrystals coated on carbon nanotubes (NiFe2O4-MWCNTs/epoxy) were synthesized by the combined precipitation-hydrothermal method in 1-30wt.% of nanoparticles. Nickel possess well interaction with microwave radiation and represents fine electromagnetic interference (EMI) shielding and by dopping it into ferrite spinel structures, does not show any tendency to oxidation. Well-dispersed NiFe2O4-MWCNTs/epoxy nanocomposite prepared by new in-situ polymerization method. First, NiFe2O4-MWCNT nanoparticles ultrasonicated in acetone and after mixing with epoxy resin ultrasonicated again. Finally, hardner added to the composite and tuned temperature for evaporating solvent. X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) confirmed the synthesizing NiFe2O4 nanoparticles. Saturation magnetization value of NiFe2O4-MWCNTs is about 29emu/g with very low remanence and coercivity content, which revealed that the NiFe2O4-MWCNTs is ferromagnetic nanocrystal. Transmission electron microscopy (TEM) used to characterize the distribution of NiFe2O4 nanocrystals on the surface of MWCNTs. The TEM images show that NiFe2O4 nanocrystals have a mean size of 12nm, and completely coated on the exterior surface of MWCNTs. The obtained results of reflection loss revealed that the maximum values of reflection loss of the NiFe2O4-MWCNTs/epoxy increase by enhancing the content of nanoparticles until 10wt.% and decreases in 30wt.%.