1070-4272/04/7705-0830C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 5, 2004, pp. 830!834. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 5,
2004, pp. 835!839.
Original Russian Text Copyright + 2004 by Verezhnikov, Min’kova, Poyarkova.
AND POLYMERIC MATERIALS
Flocculation of Butadiene!Styrene Latex with Polymeric
Ammonium Salts of N,N-Dimethylaminoethyl Methacrylate
and Mineral Acids
V. N. Verezhnikov, T. V. Min’kova, and T. N. Poyarkova
Voronezh State University, Voronezh, Russia
Received January 14, 2004
Abstract-The flocculation performance of cationic polyelectrolytes (polymeric ammonium salts of
N,N-dimethylaminoethyl methacrylate) and mineral acids (HCl, HNO
) in recovery of rubber
from SKS-30 ARK butadiene3styrene latex was studied.
Flocculation of latexes using cationic polyelectro-
lytes is a promising salt-free procedure to recover
rubbers after emulsion copolymerization . These
flocculants eliminate discharge with wastewater of
sodium chloride consumed in significant amounts in
coagulation of latexes by the existing procedures
(up to 1000 kg per ton of rubber). Therefore, study of
latex flocculation with polymers and search for new
effective polymeric flocculants are of particular im-
portance; and among them, polymers based on amino-
alkyl methacrylates show much promise  due to
their high reactivity in (co)polymerization, simple
preparation of monomers and polymers, and their high
solubility in water.
As the monomers are bases, it seems the most feas-
ible to prepare flocculants in the form of polymeric
ammonium salts of aminoalkyl methacrylates and
mineral acids. Synthesis and polymerization of am-
monium salts of N,N-dimethylaminoethyl methacry-
late (DM) and mineral acids (HCl, HNO
) were studied in , and the electrical conduc-
tivity of solutions and acid3base properties of poly-
DM ammonium salts (PDMASs) were analyzed in
[6, 7]. It was found that PDMASs in aqueous solu-
tions are polyelectrolytes with basic properties and,
depending on the salt structure, the pH of their half-
, is within 6.237.2 range .
The flocculation power of these polyelectrolytes in
recovery of rubber from latexes is of particular impor-
tance. In this work we studied the flocculation per-
formance of PDMAS and above mineral acids in their
interaction with industrial latex of butadiene3styrene
rubber as influenced by the salt structure, concentra-
tion of the latex dispersed phase, and solution pH.
We used N,N-dimethylaminoethyl methacrylate
purchased from Metakor company (Yaroslavl, Russia).
According to the potentiometric titration data, the con-
tent of amino ester in the initial sample was 99.8%.
Chemically pure grade mineral acids (HCl, HNO
) were used in the experiments.
The poly-DM ammonium salts were prepared by
(A) The initial monomeric salts were synthesized
in isopropanol according to . The corresponding
hydrochlorides were obtained by passing gaseous
hydrogen chloride and polymerized in aqueous solu-
tion (50% weight fraction) without initiating agent
at the following temperatures, oC: 100 DM.HCl,
, and 80 DM.H
was performed for 334 h until a viscous difficult-to-
stir mass was obtained.
(B) The monomeric salts were prepared and poly-
merized in aqueous solution without isolation of salts
from the reaction mixture. Equivalent amounts of DM
were added to the aqueous acid solutions at two tem-
perature modes: 035 (procedure B
) and 20325oC
). After neutralization, the concentra-
tion of the resulting salt was determined by poten-
tiometric titration, which was performed in aqueous
alcohol with a 0.5 M alcoholic solution of potassium
hydroxide. For polymerization, the solutions were
heated to the same temperatures (as in method A) for
The intrinsic viscosity (see table) of the resulting
polymeric salts PDMAS.HCl (I), PDMAS.HNO
(III), and PDMAS.H