Iran Occupational Health

Background and aims: X-band with 8-12.5 frequencies range has various applications such as air control traffic, navy communication and etc. Uncontrolled exposure with microwave can lead to adverse effect on workers. Application of the shielding is superior control for prevention of microwave exposure, now. This study investigated the effect of dispersion on shielding effectiveness improvement about a novel nanocomposit shiled.

MethodS: Nanocomposites prepared by epoxy resin and nano nickel oxide (7wt %) with 2, 4 and 6 mm thicknesses. In order to investigate the effect of dispersion , 10 and 66 minutes was considered as mixing time . Nanoparticles characterized by X-ray Diffraction and Field Emission Scanning Electron Microscope. Shielding effectiveness measured with vector network analyzer.

Results: Dispersion of nanoparticles in group 2-nanocomposites was better than group 1- nanocomposites. Average of percentage attenuation in group 2-nanocomposites was better than group 1- nanocomposites. The Average of shielding effectiveness for three thicknesses in group 1 was 46.5, 69.03 , 70.83 and for group 2 was 52.02%, 78.48% and 84.14 %dB, respectively. Maximum attenuation obtained by the 6mm thickness in group 2- nanocomposites at 8.8 GHz frequency (91.12%). The Average of shielding effectiveness increased with increasing the thickness.

Conclusion: with increasing the mixing time, the dispersion and shielding effectiveness be improved. These nanocomposites could be used as appropriate shielding for exposure control of X-band frequency in workplace and nanocomposite with 4mm thickness is appropriate shield in this study. Both 4mm and 6mm thicknesses in group2 are useful in specific frequency such as 8.8 and 12.5 GHz .the average of percentage attenuation for above thicknesses is more than 87%. Keyword: electromagnetic shielding, microwave, nanocomposite, nickel oxide, electromagnetic radiation, dispersion