1070-4272/03/7608-1319 $25.00 C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 8, 2003, pp. 1319!1322. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 8, 2003,
Original Russian Text Copyright + 2003 by Nikulin, Verezhnikov, Poyarkova, Shmyreva.
AND POLYMERIC MATERIALS
as Coagulant for Butadiene-Styrene Latices
S. S. Nikulin, V. N. Verezhnikov, T. N. Poyarkova, and Zh. V. Shmyreva
Voronezh State University, Voronezh, Russia
Voronezh State Academy of Forestry Engineering, Voronezh, Russia
Received April 16, 2003
Abstract-Coagulating action of 2,2,4-trimethyl-1,2-dihydroquinoline hydrochloride in separating butadiene-
styrene rubber from latex is studied, and the properties of vulcanizate based on rubbers prepared by this
procedure are examined.
The use of nitrogen-containing compounds in sep-
aration of rubber prepared by emulsion copolymeriza-
tion allows, in some cases, a considerable decrease in
the consumption of coagulating agents . Of spe-
cial interest in this regard are polymeric quaternary
ammonium salts and, in particular, poly(N,N-dimeth-
yl-N,N-diallylammonium chloride) (PDDAC), which,
as shown in a series of publications , demon-
strates high performance in separating rubber from
latices when taken both separately and in combination
with other coagulating agents.
The possibility of using PDDAC in a real process
was confirmed in pilot tests . However, industrial
application of this reagent is limited by its short sup-
ply and considerably higher cost as compared to such
commonly used coagulant as NaCl. Therefore, search-
ing for new more readily available coagulants allow-
ing not only reduction of the mineral salt consumption
or its exclusion from the process at all, but also im-
provement of the performance characteristics of the
resulting products (rubbers, rubber stocks and vul-
canizates) is a topical task.
Desired nitrogen-containing compounds for sep-
arating rubber from latex must have a dual function,
operating as a coagulant and antioxidant (stabilizer of
polymer), provided that, in the course of coagulation,
they will enter the composition of the resulting rub-
ber crumb and will not be removed from the system.
The antioxidant properties of a coagulant will allow
lower consumption or complete elimination of ex-
pensive antioxidants, which are introduced into the
latex prior to the coagulation stage in production of
emulsion rubber. This should compensate to a con-
siderable extent for the expenses for acquisition of
an expensive nitrogen-containing coagulant, making
rubber separation from the latex more cost-efficient.
In , it was suggested to use for salt-free coagula-
tion of latices of butadiene-styrene and butadiene-ac-
rylonitrile rubbers, a coagulant, poly(N-3,5-di-tert-
butyl-4-hydroxytolyl) ethylenimine synthesized by the
Mannich reaction, which also exhibits stabilizing
properties for rubber. A similar bifunctional polymeric
coagulant was also described in .
In this context, low-molecular-weight cationic re-
agents, such as 2,2,4-trimethyl-1,2-dihydroquinoline
(DHQ), which can inhibit oxidation processes 
and increase the stability of polymers against ozone
aging , may be promising. The initial dihydro-
quinoline is a condensation product of such readily
available organic compounds as aniline and acetone
Previously  we reported on a study of the ki-
netics of coagulation and coagulating performance of
DHQ hydrochloride (DHQHC) in separating rubber
from latex of emulsion polybutadiene (EPB) produced
by the industry in limited amounts. It was of interest
to assess the efficiency of DHQ salts in separating
butadiene-styrene rubber as the most widely used rub-
ber of general purpose.
The goal of this study was to estimate the coagulat-
ing efficiency of the water-soluble organic ammonium
salt, DHQHC, in separating commercial butadiene-
styrene rubbers from latices.
DHQ salts were prepared as in [9, 10].