1070-4272/02/7503-0461$27.00C2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 3, 2002, pp. 461! 464. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 3,
2002, pp. 472!475.
Original Russian Text Copyright C 2002 by Verezhnikov, Nikulin, Poyarkova, Vostrikova.
AND POLYMERIC MATERIALS
Flocculating Power of Poly-N,N-dimethyl-N,N-diallylammonium
Chloride of Various Molecular Weights
V. N. Verezhnikov, S. S. Nikulin, T. N. Poyarkova, and Yu. G. Vostrikova
Voronezh State University, Voronezh, Russia
Received October 30, 2001
Abstract-The amount of precipitated rubber in flocculation of SKS-30 ARK butadiene3styrene latex was
studied as influenced by the concentration of poly-N,N-dimethyl-N,N-diallylammonium chloride cationic
polyelectrolyte at various temperatures and concentrations of the latex dispersed phase.
Recently, considerable attention has been given
to the use of quaternary ammonium polymeric salts as
coagulating agents for recovery of rubbers after emul-
sion copolymerization . This is due to the fact
that the amount of these salts required for recovery
of rubbers from latexes is 503100 times smaller as
compared with the common coagulating agents (sodi-
um chloride) . As a result, environmental pollution
with aqueous salt wastes, which is the main disad-
vantage in production of emulsion rubbers, can be
significantly decreased, and thus utilization of quater-
nary ammonium salts in production of synthetic rub-
ber is rather promising. At the same time, published
data are insufficient for industrial use of these salts.
For example, significant scattering in molecular
weights and pH of their aqueous solutions can strong-
ly affect the consumption of the reagent required for
complete coagulation of the latex. Since under the real
industrial conditions the recovery of rubber from
a latex depends on such factors as concentration of
the dispersed phase and temperature, study of the
effect of these parameters is of particular importance.
In , we used ungraded commercial cationic poly-
chloride (PDMDAAC) as flocculating agent. It was
found that the dependence of the fraction of the pre-
cipitated polymer on the concentration of the cationic
polyelectrolyte passes through a maximum only at
relatively small concentrations of the dispersed phase
(;50 g l
). At higher rubber concentrations in the
latex, the flocculation optimum is lost.
In this work, we studied the flocculating power of
PDMDAAC of various molecular weights as in-
fluenced by the temperature and concentration of the
We used SKS-30 ARK brand commercial buta-
diene3styrene latex containing soap emulsifiers based
on disproportionated rosin and fatty and resin acids
of tall oil.
In the first stage, PDMDAAC was subjected to
fractional precipitation in the water3acetone system.
The initial commercial PDMAAC sample (; 40 wt %
concentration) was diluted with water to nearly 10%
concentration. Fractionation was performed by addi-
tion of acetone into the resulting PDMAAC aqueous
solution with subsequent separation of the correspond-
ing fractions. Then each fraction was dried in an oven
at 90oC for 43 6 h to remove acetone. We studied
three PDMAAC fractions with
of 172000, 62000,
and 16 000. The molecular weights were calculated
from the Mark3Kuhn3Houwink equation with the fol-
lowing constants: K = 1.12 0 10
and a = 0.82 .
The coagulating power of PDMAAC samples with
was evaluated gravimetrically (from the
weight of the resulting coagulum) and visually (from
the serum transparency).
Coagulation tests were performed as follows.
A sample of the SKS-30 ARK latex with a given con-
centration of the dispersed phase (1.0, 1.5, 2.0, 3.0,
5.0, and 10 wt %) was charged into a vessel equipped
with a stirrer and a thermometer and then placed
in a thermostat heated to a required temperature.
After heating for 10 min, the required amounts of
a PDMAAC aqueous solution and 2% sulfuric acid
were added with stirring. The content of the acidifying
agent was constant (15 kg per ton of rubber). The
resulting coagulum was separated from the serum and
dried at 75380oC.
The dependence of the degree of coagulum re-