No abstract

A novel lightweight multi-wall carbon nanotubes (MWCNT) based polymethylmetacrylate (PMMA) composite is shown to present high electromagnetic (EM) shielding. EM shielding effectiveness (SE) was investigated in the frequency range 26-37 GHz (Ka-band). It was found that SE of the given composites strongly depends on MWCNT content. The highest EM attenuation reaching À37 dB at 28 GHz was observed for polymer film comprising 10 wt.% of MWCNT. Data on SE correlates well with the electrical conductivity measured by four-probe technique and by broadband dielectric spectroscopy (20 Hz-1 MHz). Both microwave and low-frequency analysis demonstrate low percolation threshold (lower than 1 wt.%) for the produced MWCNT/PMMA composites. At the same time significant electromagnetic interference absorbance demonstrates the contribution of the absorbance mechanisms specific for carbon nanostructures different of the main conductance mechanism.