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Abstract |
Effect of Ultrasonic Treatment on
Aqueous Dispersion of Inorganic and Organic Pigments in Presence of
Water-Soluble Polymers and Surfactants
I.Kuzkina, N.A.Bulytchev, V.P.Zubov
(Moscow Academy of Fine Chemical Technology, Moscow, Russia); I.A.Arutunov
(Moscow Academy of Fine Chemical Technology, Moscow); N.A.Serebryakova
(Institute of Physical Chemistry, Russian Academy of Sciences, Moscow, Russia);
O.V.Abramov (Institute of General and Inorganic Chemistry of RAS, Moscow,
Russia)
e-mail:
LUTT@IGIC.RAS.RU
The
stability of aqueous dispersions of inorganic pigments Ti02 (rutile) and Fe203
(red) under ultrasonic treatment in the presence of
ethylhydroxy(ethyl)cellulose (EHEC) was studied. The ultrasonic generator "UZDN-2"
with frequency of 22 kHz and intensity of 30 W/cm2 was used for treatment of
pigments dispersions. Without polymer
the ultrasonic treatment of a dilute Ti02 and Fe203 aqueous dispersions results
in a rapid complete coagulation of the dispersions. In the presence of EHEC a
stabilizing effect was observed, which depends on the polymer concentration and
the duration of the ultrasonic treatment. Ultrasonic treatment results in a
reduction of particles size (from 1 mcm to 0.3 mcm) and the narrower particle
size distribution. It was supposed that the
ultrasonic treatment results not only in an effective deagglomeration of
particles, but also initiates adsorption of polymer on freshly activated
surfaces. The evidences of polymer adsorption on the pigments surface and
creation of the stabilizing layer were obtained by measuring the æ - potential
by the electrokinetic sonic amplitude (ESA) method and by the method of IR -
spectroscopy. As an organic pigment we
used copper phthalocyanine (CuPc). Its surface is very hydrophobic and not
wettable with water. Earlier we showed that the wetting effect was observed in
the presence of polyvinyl alcohol (PVA) with residual acetyl groups content of
10-20% and molecular weight of 10000-11000. Wetting of the surface of pigment
results in its transfer into the aqueous phase and the latter gets bright-blue
color. The increase of color intensity goes in parallel with efficiency of
stabilizing action of PVA and thus it could be used as measure of stabilization
action. The values of optical density of CuPc dispersions with separated solid
phase becomes significantly higher in the case of ultrasonic treatment of the
dispersions. Similar effects were
observed for CuPc aqueous dispersions when non-polymeric and anionic
surfactants in combination with ultrasonic treatment were used.
Section
: 11