1070-4272/03/7610-1659 $25.00 C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 10, 2003, pp. 1659!1661. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 10, 2003,
Original Russian Text Copyright + 2003 by Val’tsifer, Gubina.
AND POLYMERIC MATERIALS
Rheological and Electrical Properties
of an Oligomeric Formulation
as Influenced by Fractional Composition of Conducting Filler
V. A. Val’tsifer and N. A. Gubina
Institute of Technical Chemistry, Ural Division, Russian Academy of Sciences, Perm, Russia
Received April 18, 2003
Abstract-The effect of bifractional composition of conducting filler on the electrical and rheological prop-
erties of oligomeric compound was studied.
Conducting polymeric materials are frequently pre-
pared by addition of conducting dispersed components
[1, 2]. When a conducting component is added in
amount exceeding certain fraction, a three-dimensional
network of contacting particles is formed, and this
structure determines the conductivity of the polymeric
compound. Usually, polymeric compounds become
conducting at a volume fraction of coarse filler of
23325 vol % .
It is known that finely dispersed components, e.g.
carbon black, tend to structurize in an oligomeric
medium [4, 5] and form continuous structures extend-
ing over the entire system, making it conducting .
Formation of such structures obviously affects the rhe-
ological properties of the polymer, because they increase
the energy of dissipation in a flowing system, i.e.,
the viscosity of the system grows. The volume content
of the carbon black at which an oligomeric compound
becomes conducting does not exceed 1 vol %.
To develop conducting polymers using conducting
dispersed components, it is necessary to understand
the patterns of formation of continuous networks from
disperse particles in an oligomeric binder. In this
study, we analyzed the rheological and electrical prop-
erties of oligomeric suspensions as influenced by
an electrically conducting filler.
The structuring of carbon black consisting of coarse
and fine fractions in the oligomeric dispersion medi-
um was studied on a special rheological-conducto-
metric device  equipped with a rheoviscometer of
the Rheotest-2.1 type and a digital unit for data pro-
cessing, interfaced to PC.
The experiments were performed using nongranu-
lated carbon black (specific surface area 100 m
and graphite (particle size 50380 mm), with butadiene-
isoprene oligomer (M 5000) as a dispersion phase.
The formulations studied were prepared in a vacuum
mixer (250 rpm, 1000 Pa) in the course of 30 min at
a temperature of 60oC in the water jacket of the stirrer.
The mixture was placed in the measuring cell of the
rheological-conductometric device, and the cell was
thermostated for 1 h. Then, the initial parameters of
the device were set, the inner structure of the formula-
tion in the measuring cell was destroyed at a shear
rate of about 2 0 10
, and the processes occurring
in the compound were studied.
The increase in the conductivity of the formulations
indicated that the carbon black particles are involved
in structuring and form three-dimensional (3D) con-
ducting agglomerates extending over the entire vol-
ume of the measuring cell. As seen from microscopic
data, the current passing through the formulation con-
taining continuous networks of carbon black particles
is proportional to the number of particle macrochains
in the system.
Finely disporsed particles can form continuous
networks extending over the entire system and affect-
ing the macroproperties of the oligomeric compound,
especially its rheological properties; primarily, the
dissipation energy of the compound flow (or its vis-
cosity) must increase. In the case of a conducting filler
(e.g., carbon black), formation of 3D continuous net-
works would strongly affect the formulation prop-
erties, making the material conducting. Obviously,