ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 10, pp. 1662−1666. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © V.N. Verezhnikov, S.S. Nikulin, A.V. Zorina, A.K. Ermolaeva, N.I. Kretinina,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89,
No. 10, pp. 1345−1350.
AND POLYMERIC MATERIALS
An important aspect of improvement of emulsion
rubber production is reduction of concomitant unfavor-
able environmental factors. This can be reached by dif-
ferent ways, in particular, by ﬁ nding new economically
efﬁ cient and environmentally sound solutions in the
step of rubber recovery from the latex. The following
approaches are promising in this respect: (1) develop-
ment of new “biologically soft” coagulants, including
those that are captured by the rubber and do not get into
wastewaters [1, 2]; (2) search for cheap, readily avail-
able coagulating agents, primarily among various pro-
duction wastes ; (3) development of procedures for
precoagulation treatment of latex in various physical
ﬁ elds for reducing its aggregative stability and speciﬁ c
coagulant consumption in rubber recovery.
This study was aimed at determining how the pre-
coagulation mechanical treatment of a latex inﬂ uences
its aggregative stability under the action of a coagulant
(sodium chloride, betaines) and the speciﬁ c coagulant
consumption in rubber recovery and how the mechani-
cal treatment of different intensity can affect the state of
adsorption hydrate protective shells of the emulsiﬁ er on
the surface of latex particles.
Experiments were performed with latex of SKS-
30 ARK butadiene–styrene copolymer commercially
produced by Voronezhsintezkauchuk (Russia), which
had the following characteristics: polymer concentration
208.5 g L
, pH 9.6, mean hydrodynamic particle radius
(data of dynamic light scattering) 39.1 nm.
As coagulants we used sodium chloride (chemically
pure grade) and N,N-dimethylaminopropyl carboxy be-
taines derived from fatty acids (CB FA) of vegetable oils
(sunﬂ ower-seed, palm, coconut, palm kernel oils). The
betaines were synthesized at the Chair of Organic Chem-
istry, Voronezh State University . The molecular struc-
ture of these products can be described by the formula
where R are residues of vegetable oil fatty acids.
Precoagulation mechanical treatment of the latex
was performed in shear stress ﬁ eld using a device with
Effect of Mechanical Treatment on the Aggregative Stability
of Latex and on Consumption of Coagulants
in Rubber Recovery
V. N. Verezhnikov
*, S. S. Nikulin
, A. V. Zorina
, A. K. Ermolaeva
, and N. I. Kretinina
Voronezh State University, Universitetskaya pl. 1, Voronezh, 394036 Russia
Voronezh State University of Engineering Technologies, pr. Revolutsii 19, Voronezh, 394000 Russia
Received October 4, 2016
Abstract—The effect that mechanical treatment of SKS-30 ARK latex by mixing in a gap between coaxial
cylinders exerts on the latex resistance to an electrolyte and on the polymer yield in coagulation with two types
of coagulants, sodium chloride and N,N-dimethylaminopropyl carboxy betaines derived from vegetable oil fatty
acids, was studied. Such treatment decreases the rapid coagulation threshold and increases the coagulum yield.
The effect is caused by partial breakdown of hydrate shells of particles as a result of mechanical action in a shear
stress ﬁ eld.