Russian Journal of Applied Chemistry, 2009, Vol. 82, No. 4, pp. 618−621.
Pleiades Publishing, Ltd., 2009.
Original Russian Text
N.A. Nesterova, I.I. Gavrilova, E.F. Panarin, 2009, published in Zhurnal Prikladnoi Khimii, 2009, Vol. 82, No. 4, pp. 624−627.
AND POLYMERIC MATERIALS
Radical Copolymerization of N-Vinylformamide
with Unsaturated Carboxylic Acids
N. A. Nesterova, I. I. Gavrilova, and E. F. Panarin
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received January 21, 2008
Abstract—Radical precipitative copolymerization of N-vinylformamide with acrylic and methacrylic acids in
isopropanol at 60°C, with azobisisobutyric acid dinitrile as initiator, was studied. The conditional values of the
relative reactivities were found: r
= 0.068 ± 0.008 and r
= 1.638 ± 0.025 for the N-vinylformamide–methacrylic
acid copolymer and r
= 0.15 ± 0.03 and r
= 0.19 ± 0.09 for the N-vinylformamide–acrylic acid copolymer.
Poly-N-vinylamides are of considerable interest
because of their wide use in medicine and biotechnology
. The best studied of these are polyvinylpyrrolidone
and copolymers of N-vinylpyrrolidone with comonomers,
containing various functional groups. The latter are used
as carriers of biologically active substances. Less studied
are N-vinylamides with an open chain and polymers
based on these compounds. Of particular interest among
N-vinylamides is N-vinylformamide (N-VFA), which
contains a formyl group easily removable by acid
hydrolysis, and water-soluble copolymers on its basis.
However, data on the reactivity of N-VFA in homo- and
copolymerization, reported in the scientiﬁ c literature,
are scarce. In this context, of indubitable scientiﬁ c and
practical interest is a study of the copolymerization of
N-VFA with functional monomers.
The aim of this study was to examine the copolymerization
of N-vinylformamide with unsaturated carboxylic acids,
methacrylic (MAC) and acrylic (AC), in isopropanol.
The copolymerization of N-VFA with MAC and AC in
isopropanol occurs by the heterophase mechanism. This is
due to the presence in the copolymers of vinylformamide
units forming ﬁ rm hydrogen bonds N–H...O=C both
with the neighboring carboxyl-containing units in the
polymer chain and between macromolecule chains [1,
2]. Just this circumstance hinders dissolution of the
resulting copolymers in alcohols. The precipitative
copolymerization cannot be described in terms of the
classic theory of radical copolymerization, in which the
relative activities of monomers are determined solely
by the chemical structure of monomers and radicals.
Therefore, we consider the calculated copolymerization
constants and structural parameters of the polymers to
N-Vinylformamide, AC, and MAC purchased from
Aldrich were purified by vacuum distillation: bp
65.0°C (4 mm Hg), bp 48.0°C (15 mm Hg), and bp
163.6°C (12 mm Hg), respectively. Azobisisobutyric acid
dinitrile (AAD) was twice recrystallized from ethanol,
The copolymerization was performed in isopropanol
at 60.0°C in sealed ampules in an inert medium (argon),
with AAD as initiator. The copolymers were white
powders, which were separated on a Schott ﬁ lter, washed
with acetone, and dried in a vacuum at room temperature
to constant weight. The characteristic viscosity of the
copolymers was determined in 0.2 M NaCl at 25°C with
an Ubbelohde viscometer. All the copolymers VFA–AC
and VFA–MAC are soluble in water, with the exception
of VFA–MAC samples containing more than 20 mol %
MAC units, which are easily dissolved in water in the
The fractionation was performed from a 0.6% aqueous
solution of sodium chloride by the fractional precipitation
method, with a 90 : 10 mixture of acetone and isopropanol
as the precipitating agent. The fractions were puriﬁ ed by
dialysis and subjected to freeze drying.