Synthesis and electromagnetic absorption properties of polypyrrole/BaFe12O19–Ni0.8Zn0.2Fe2O4/multi-walled carbon nanotube composites

The nanocomposite of hard ferrite (BaFe12O19)/soft ferrite (Ni0.8Zn0.2 Fe2O4) was prepared by using a sol–gel method, and then the polypyrrole/nanocomposite ferrite/multi-walled carbon nanotube composites were fabricated by an in situ polymerization process. Experimental results, such as X-ray diffraction (XRD), transmission electron microscope (TEM), fourier transform infrared (FTIR) and Raman spectra analyses indicated the formation of PPy and BaFe12O19–Ni0.8Zn0.2Fe2O4 on the surface of carbon nanotubes. The conductivities of the composites were enhanced with the increasing of MWCNTs׳ content and the value reached 19.514 S/cm in the presence of 30% MWCNTs. However, the magnetic properties did not show any obvious changes. The electromagnetic properties of MWCNTs (5%) composites exceeding −10 dB ranged from 8.5 to 10.3 GHz and the maximum loss value was −25.46 dB at 8.9 GHz. The introduction of MWCNTs had an important influence on the electrical and microwave absorbing properties of the nanocomposite.