ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 4, pp. 682! 686. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + V.N. Verezhnikov, V.A. Sedykh, N.A. Shabanova, M.N. Sergeeva, M.S. Bederkin, 2008, published in Zhurnal Prikladnoi Khimii,
2008, Vol. 81, No. 4, pp. 645! 649.
AND POLYMERIC MATERIALS
Effect of Dispersity and Drying Mode of Silica
on Deformation-Strength Properties of Latex Films
V. N. Verezhnikov, V. A. Sedykh, N. A. Shabanova,
M. N. Sergeeva, and M. S. Bederkin
Voronezh State University, Voronezh, Russia
Voronezh State Technological Academy, Voronezh, Russia
Mendeleev Russian University of Chemical Engineering, Moscow, Russia
Received November 15, 2007
Abstract-Effect of dispersity, content, and nature of silica on the deformation-strength parameters of latex
films obtained under various conditions was studied.
An effective way to modify properties of polymeric
materials is to introduce various fillers (solid, liquid,
or gaseous). Caoutchouc can be reinforced with solid
fillers with particle sizes of 5 to 1000 nm, with fil-
lers having particles 10 to 50 nm in size exhibiting
the strongest reinforcing properties . The most
frequently used solid fillers are technical-grade carbon
(carbon black) or silica in the form of a precipitated
silicon dioxide (white carbon black, perkasil, etc.).
A polymer is filled by its direct mixing with a filler
or by introduction of the filler in the latex stage. In-
troduction of a filler into the latex yields a more uni-
form distribution of components, compared with in-
troduction of fillers into a dry caoutchouc in a rolling
mill of a rubber mixer, and diminishes the energy
expenditure for mixing.
A promising reinforcing filler is colloid silica.
Modern industry manufactures colloid silica in
the form of a hydrosol that is, as a rule, stabilized
. Silica particles have a spherical
shape and their size (diameter) is approximately 6 to
30 nm, depending on a brand. Both mono- and poly-
dispersed sols are manufactured. A filler of this kind
can find use in production of various rubber articles,
and especially thin-walled articles fabricated by dip-
ping (gloves, bladders, etc.)
In this communication, results obtained in a study
of the influence exerted by the dispersity of silica on
the deformation-strength characteristics of latex films
produced by drying under various conditions are re-
The latex films were produced from an SKD-1S
polybutadiene carboxylate latex manufactured by
Voronezhsintezkauchuk Open Joint-Stock Company.
The latex was a product of joint emulsion polymeriza-
tion of butadiene with methacrylic acid (about 1 %)
in the presence of sodium alkylbenzene sulfonate. As
active fillers were used silica hydrosol of Sialit-30
brand (Silikat Private Company) and white carbon
black of BS-100 brand. The particle size d of silica
in the hydrosol was 6.3 nm (according to the results
of adsorption titration by the Sears method ). Prior
to introduction of white carbon black into the latex,
an aqueous dispersion was preliminary prepared. For
this purpose, a weighed portion of white carbon black
(~30 g) and water (~170 ml) were introduced into
a ball mill, and grinding was performed for approx-
imately 10 h. The size of silica particles in the re-
sulting suspension and that of polymer particles in
the latex were determined by the optical method with
a FEK-56 photoelectrocolorimeter to be 303 and
110 nm, respectively.
The latex films were produced by casting-and-dry-
ing on cellophane. The films were dried in two modes:
at 60oC for 120 min ([mild] drying) or at 140oC for
503 60 min ([severe] drying).
To obtained filled films, a mixture of a latex and
a silica hydrosol or a suspension of white carbon
black was preliminarily prepared with required rela-