ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 1, pp. 97−102. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © A.A. Lipin, A.V. Shibashov, A.G. Lipin, 2015, published in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 1, pp. 103−108.
Kinetics of Polymerization of Acrylamide
in a Concentrated Aqueous Solutions
A. A. Lipin, A. V. Shibashov, and A. G. Lipin
Ivanovo State University of Chemistry and Technology, pr. Sheremetevskii 7, Ivanovo, 153000 Russia
Received May 23 2014
Abstract—Experimental studies of acrylamide polymerization initiated by a redox system in concentrated aqueous
solutions were conducted under isothermal conditions. A mathematical model of the acrylamide polymerization
in concentrated aqueous solutions, which allows predicting the monomer conversion and molecular weight of
polyacrylamide synthesized, was proposed in view of a change in a initiation efﬁ ciency and chain termination rate
upon an increase in a viscosity of the polymerization system. A comparison of experimental data with calculations
was performed based on the developed mathematical model.
Synthesis of water-soluble polymers by polymerizing
of monomers in concentrated aqueous solutions is highly
efﬁ cient and environmentally safe process. This method
has several advantages over known suspension and
emulsion polymerization, e.g., reducing a consumption
of a monomer by eliminating the formation of latex losses
with water; more complete use of the heat of reaction;
a decrease in labor costs by reducing the number of
separate operations. Furthermore, it does not require the
use of large amounts of demineralized water, dispersant,
and processing of wastewater.
The aim of this study is to develop a mathematical
model describing the kinetics of polymerization of
acrylamide in concentrated solutions, which could be
used under conditions of real manufacturing. For testing
an adequacy of the model experimental studies of
acrylamide polymerization initiated by a redox system
were conducted in the aqueous solution under isothermal
Traditionally the acrylamide polymerization is carried
out in a 6–8% aqueous solution. The aqueous solutions
containing 30% acrylamide were used in the experiments.
The reaction was initiated by the redox system potassium
persulfate–sodium thiosulfate (PPS–STS). Use of the
redox system instead of initiator of the peroxide type
allows the synthesis at much lower temperature.
Residual monomer content was determined by the
bromide–bromate method , a kinematic viscosity
of 0.5% aqueous solution of the reaction mixture, by
a viscometer VPZh. The polymerization process was
carried out in the temperature range of 20–40°C at a
concentration of the initiators: PPS 1.1 × 10
–4.4 × 10
STS 1.6 × 10
–6.4 × 10
Figures 1 and 2 show the original monomer conversion
and a viscosity of the 0.5% aqueous solution of the
reaction mixture vs. the polymerization duration at various
temperatures of the process. From these curves it can be
seen that for each temperature there is a certain conversion,
above which the rate of polymerization decreases rapidly.
This fact can be explained by the diffusion limitation of
elementary reactions, which increases with the viscosity
of the reaction mixture. Indirectly this is conﬁ rmed by the
fact that the characteristic value of the conversion rises
upon the increase in the process temperature and, hence,
upon a reduction in the viscosity of the reaction medium.