Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 5, pp. 921−923.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
M.F. Galikhanov, T.K. Pavlova, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 5, pp. 868−870.
A Study of the Electret State of Polyethylene Formulations
with a Ferroelectric
M. F. Galikhanov and T. K. Pavlova
Kazan State Technological University, Kazan, Tatarstan, Russia
Received October 13, 2009
Abstract—A method for simultaneous desalting and deoxygenation of feed and extra water was developed for
through steam generators using ion-exchange mixed bed ﬁ lters and the ﬁ lter with ferrous hydroxide electron ion
exchanger which eliminates the stage of thermal deaeration.
Corona-electrets based on formulations with high-
pressure polyethylene and a dispersed ferroelectric
ﬁ ller, potassium nitrate, were studied. The effect of the
ﬁ ller content on the electret characteristics of composite
materials was revealed. The thermal stability of the
electret state of polyethylene and its formulations with
2 vol % potassium nitrate was examined.
The practical application area of polymeric electrets
covers various ﬁ elds of national economy: electronics,
machine building, medicine, etc. [1–3]. Being intensively
developed since the beginning of the XX century, the
technology of electret fabrication has made a signiﬁ cant
advance: numerous materials and technologies have been
developed and make it possible to ﬁ nd new application
areas for materials of this kind .
One of new classes of electrets are formulations of
polymers with ferro- and piezoelectrics. An advantage of
systems of this kind is the possibility of a comparatively
easy control over their properties by using various ﬁ llers
and changing their content and technological parameters
of their manufacture [5–9]. However, the electret state
itself is rarely discussed when studying systems of this
kind, with the attention focused on the piezoelectric
properties of a formulation as a whole.
The aim of this study was to develop electrets
based on polyethylene formulations with a powdered
ferroelectric, examine their properties, and elucidate
mechanisms of the phenomena observed.
As objects of study were chosen high-pressure
polyethylene (HPPE) of 11503-070 brand [GOST (State
Standard) 16337–77), with a density of 0.92 g cm
a ferroelectric (FE), potassium nitrate, with a density of
2.11 g cm
, Curie point T
of about 250°C and mp
The polymer was mixed with the ﬁ ller on laboratory
microrollers at a temperature of 135 ± 5°C and mixing
time of 3 min. Plates with a thickness of 0.4 mm were
prepared by compaction in conformity with GOST
12019–66 at a temperature of 170 ± 5°C and compaction
time of 5 min. The polymer plates were polarized in the
ﬁ eld of a corona discharge with an electrode constituted
by 196 pointed needles uniformly distributed over an
area of 49 cm
in the form of a square. The distance
between a plate and the electrodes was 20 mm at
a polarization voltage of 5 kV and polarization time of
90 s. Before the polarization, the plates were kept in an
oven at 90°C for 10 min.
The electret potential difference of the samples,
UEPD, was measured using the noncontact inductive
method with a vibrating electrode in conformity with
GOST 25209–82. The time elapsed from the polarization
of a plate to the ﬁ rst measurement of its surface potential
was 1 h. The electrets were stored at room temperature
in a non-short-circuited state.
Spectra of thermally stimulated currents (TSC)