Nanocomposites and nanomaterials

Complex permittivity of polymer-based composites with carbon fillers at microwave band
Yakovenko O.S.1, Matzui L.Yu.1, Vovchenko L.L.1, Lazarenko O.A.1, Perets Yu.S.1, Lozitsky O.V.1, Trukhanov A.V.2, Trukhanov S.V.2
1 Department of Physics, Taras Shevchenko National University of Kyiv, Volodymyrs’ka str., 64/13, Kyiv, 01601, Ukraine.
E-mail: alenka-ya@ukr.net
2 Scientific-Practical Materials Research Centre of the National Academy of Sciences of Belarus, P.Brovki str., 19, Minsk, 220072, Belarus.

Filled with carbon particles materials are a typical microwave composites (CMs) in recent decades [1]. But the development of such CMs remains a cornerstone since detailed microwave absorption mechanisms include quarter-wavelength cancellation theory, good impedance matching, intense conductive loss, multiple reflections and scatterings, microwave plasma loss, dielectric loss (which mainly originates from the various interfacial polarizations, plentiful dipole polarizations, and large amounts of relaxation loss) and magnetic loss (which mostly derives from natural resonance and the eddy current effect) [2].
In this paper, complex permittivity of epoxy CMs with carbon fillers (multiwall carbon nanotubes (MWCNTs), graphite nanoplatelets (GNPs)) of different content (0-10 wt. %) at frequency region 1-67 GHz have been investigated. Vector panorama Agilent Technologies N5227A-200 was used for measurements of frequency dependencies of complex permittivity of CMs at room temperature. Experimental results were analyzed using the Maxwell Garnett model.
In summary, carbon/polymer composites have been developed as highly effective microwave-absorption materials. By tailoring the content and type of carbon filler in composite and layer thicknesses, the effective absorption frequency bands can be made to cover most of the C, X, and K bands.

1.	Liu L., Kong L. B., Yin W. Y., Chen Y., Matitsine S. Microwave Dielectric Properties of Carbon Nanotube Composites // Carbon Nanotubes, Marulanda J.M. (Ed.). – 2010.- 5. P. 93 – 108.
2.	Qiao M., Lei X., Ma Y., Tian L., He X., Su K., Zhang Q. Application of yolk–shell Fe3O4@N-doped carbon nanochains as highly effective microwave-absorption material // Nano Research. – 2017.- 11, N 3. P. 1500–1519.