ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 9, pp. 1518!1521. + Pleiades Publishing, Inc., 2006.
Original Russian Text + B.M. Ginzburg, D.G. Tochil’nikov, A.A. Shepelevskii, A.M. Leksovskii, Sh. Tuichiev, 2006, published in Zhurnal Prikladnoi
Khimii, 2006, Vol. 79, No. 9, pp. 1534 !1537.
AND POLYMERIC MATERIALS
Tribological Properties of Polytetrafluoroethylene Modified
with Fullerene Black in Dry Sliding Friction
B. M. Ginzburg, D. G. Tochil’nikov, A. A. Shepelevskii,
A. M. Leksovskii, and Sh. Tuichiev
Institute of Problems of Mechanical Engineering, Russian Academy of Sciences, St. Petersburg, Russia
Ioffe Physicotechnical Institute, Russian Academy of Sciences, St. Petersburg, Russia
Tajik State National University, Dushanbe, Tajikistan
Received April 27, 2006
Abstract-The effect of fullerene black introduced (after extraction of light fullerenes from the black with
toluene) into polytetrafluoroethylene F-4 on its wear resistance and antifriction properties in sliding over steel
at contact pressures in the range 0.2!2.0 MPa was studied.
Polytetrafluoroethylene (PTFE) is one of the best
antifriction polymeric materials . However, its use
is restricted by cold flow and poor wear resistance.
Introduction of various solid fillers into PTFE leads to
a certain compromise: the wear resistance increases
at a certain deterioration of antifriction properties.
Composites based on PTFE are used in manufacture
of plain bearings, guiding devices, and seals, includ-
ing those working without additional lubrication in
vacuum and corrosive media .
It was shown in [23 4] that introduction of fullerene
into liquid lubricating oils improves their antifric-
tion and wear-resistant properties in sliding friction of
metals. Moreover, introduction of fullerene blacks
into oils (even upon extraction of most of fullerenes
from the blacks) also markedly improves the tri-
bological properties of lubricants . The possible
reason is that a large amount of fullerenes, especially
higher fullerenes, remains in the black upon extraction
of the larger part of fullerenes with aromatic solvents
. Use of various blacks of other origins produces no
effects of this kind. At the same time, the fullerene
black is a considerably less expensive material than
pure fullerenes and, upon extraction of fullerenes, is
a waste from the fullerene production, which has not
found wide use so far.
The aim of this study was to examine the effect of
fullerene black on the tribological properties of PTFE;
it was intended to use fullerene black from which ful-
lerenes were already extracted as additive to materials
in order to obtain data on the possibility of its prac-
We used as starting materials for tribological tests
polytetrafluoroethylene F-4 [GOST (State Standard)
10 007380]. The starting fullerene black was obtained
in electric-arc plasma by the Kr1atschmer3Huffman
method . Extraction with toluene as a solvent was
used to recover from the black an 8% amount of a
mixture of fullerenes (mostly C
in a 75 : 25
ratio). The fraction of residual fullerenes remaining in
the fullerene black after the extraction, found by addi-
tional prolonged extraction, did not exceed 0.23 0.3%.
However, published data suggest that the residual
amount of higher fullerenes remaining after primary
extraction with toluene in the black we used (desig-
nated as FB) is rather high [5, 7].
We introduced 1 wt % FB into the bulk of F-4 in
conformity with the same technical specifications
which were used in introduction of coal coke and pro-
duction of F-4K20 material [TU (Technical Specifica-
tion) 6-05-1412376]. As shows practical experience
, there is no point in introducing fullerene C
a fullerene black into lubricants in an amount exceed-
ing 133 wt %. Part of samples were coated with a thin
film of fullerene C
by drying a toluene solution of
directly on the sample surface. The thickness of
this film, evaluated by the concentration of the solu-