ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 10, pp. 1666!1668. C Pleiades Publishing, Inc., 2006.
Original Russian Text C M.L. Eritsyan, L.A. Gyurdzhyan, L.T. Melkonyan, G.V. Akopyan, 2006, published in Zhurnal Prikladnoi Khimii, 2006,
Vol. 79, No. 10, pp. 1686!1688.
AND POLYMERIC MATERIALS
Copolymers of Acrylic Acid with Urea
M. L. Eritsyan, L. A. Gyurdzhyan, L. T. Melkonyan, and G. V. Akopyan
Abovyan State Pedagogical University, Yerevan, Armenia
Received March 24, 2006
Abstract-Composition and rheological characteristics of aqueous solutions of acrylic acid/urea copoly-
mers were studied, including the composition dependences of the equivalent conductivity and viscosity.
There is only limited information on copolymers
of acrylic acid (AA) and urea (Ur) . These branched
copolymers are poorly soluble in common organic
solvents. Srivastava and Majki  have demonstrated
that AA/Ur copolymers are formed by the radical
mechanism via addition of the vinyl radical of AA to
the carbonyl group of urea. Together with the radical
polymerization, some condensation reactions occur,
resulting in branching of the copolymers.
To our knowledge, there is no information on
the composition of AA/Ur copolymers and their char-
acteristics, such as rheology of aqueous solutions,
conductivity, etc. To characterize the composition of
AA/Ur copolymers, we first determined their copoly-
merization constants. Then we examined the depen-
dence of the molecular weight MW of the copolymers
on the AA/Ur molar ratio in the monomer mixture,
and also the rheology and conductivity of their
All the experiments on radical polymerization were
carried out at a constant AA concentration of 2 M.
The copolymerization constants r
timated using the classic Fineman3Ross equation for
the case with no interaction between the urea-derived
radical with the corresponding monomer (r
f = r
F = [AA]/[Ur],
where f = a/b; a and b are the AA and Ur units in
the copolymer; K
, addition rate constants
the AA radical to its monomer and Ur; and [AA] and
[Ur], monomer concentrations.
The copolymerization constant r
from the Fineman3Ross plot (Fig. 1) to be 4+ 0.1.
Results on r
reveal that, in the copolymer,
each Ur unit adjoins microblocks of the AA units. In
synthesis of the copolymer of a given composition
and structure, one may expect salt formation as a re-
sult of the interaction between the carboxy group of
AA with the amino group of Ur. Such an interaction
can be both intra- and intermolecular:
The resulting copolymer films were analyzed for
ionic groups by IR spectroscopy. The spectra clearly
Fig. 1. Polymerization factor f from Eq. (1) vs. the AA/Ur
molar ratio F.