ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 2, pp. 302−307. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © E.A. Zakharychev, M.A. Kabina, E.N. Razov, Yu.A. Svetlakov, L.A. Istomin, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88,
No. 2, pp. 301−306.
AND POLYMERIC MATERIALS
Effect of Functionalization of Carbon Nanotubes
on the Radar-Absorbing Properties of Polymeric Composites
Based on Them
E. A. Zakharychev
, M. A. Kabina
, E. N. Razov
, Yu. A. Svetlakov
, and L. A. Istomin
Lobachvevsky State University, ul. Gagarina 23, Nizhni Novgorod, 603950 Russia
Sedakov Research Institute of Measurement Systems, GDP-486, Nizhni Novgorod, 603950 Russia
Received December 14, 2014
Abstract—The effect of functionalization of carbon nanotubes in a mixture of sulfuric and nitric acids on the
radar-absorbing properties of polymeric composites based on them was studied. The optimum functionalization
conditions were determined, allowing the thickness of the radar-absorbent material to be decreased by 36–46%
(with its characteristics preserved) relative to the analogous composites with unmodiﬁ ed nanotubes.
Radar-adsorbent materials (RAMs) are used for the
absorption of the incident electromagnetic radiation
(EMR) at minimal reﬂ ection level, which allows solution
of diverse problems, from the absorption of “parasitic”
radiations inside high-frequency units of various devices
to a decrease in the radiolocation visibility of military
items. Polymeric composites with carbon nanotubes
(CNTs) as RAMs have been extensively studied recently.
Various procedures are used for CNT modiﬁ cation aimed
at increasing the efﬁ ciency of EMR absorption. They
are mostly based on incorporation of various substances
(metals [1–4], alloys , oxides [6, 7], salts ), on the
surface and/or into internal voids of CNTs. Depending
on the concentration of the modifying substances, they
occur in the forms of a surface layer, of nanothreads inside
the CNTs, or of particles inside CNTs or on their surface.
Such procedures are aimed at altering the electrophysical
properties of the CNTs themselves. On the other hand,
the properties of the composites under consideration are
strongly inﬂ uenced not only by the parameters of the
nanotubes, but also by the character of their distribution in
the polymeric matrix. It is known that the initial CNTs are
distributed in the polymeric matrix nonuniformly because
of their tendency to agglomeration. The same is true for the
nanotubes modiﬁ ed by the above procedures. The widely
used way to reach uniform distribution in the polymeric
matrix is chemical modiﬁ cation (functionalization) of
CNTs with the formation of active functional groups (e.g.,
carboxy groups) on their surface. However, the effect of
CNT functionalization on the radar-absorbing properties
of polymeric composites based on them was not studied
in detail previously.
In this work we studied the radar-absorbing properties
of polymeric composites with CNTs in relation to the
CNT content and degree of functionalization.
The radar-absorbing properties were studied in
the range 52–73 GHz (millimeter wavelength range).
The devices operating in this range include those for
measuring the ﬂ ow rate, humidity, and compressibility
coefﬁ cient of gases, airplane landing systems, protected
communication systems, devices for studying rapid
processes, some medical devices, systems for detection
and high-precision following of low-ﬂ ying and mobile
surface targets, and antenna feeder systems for on-board
Our experiments were performed with CNTs of
grade Taunit-M [TU (Technical Speciﬁ cation) 2166-