ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 1, pp. 122!130. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + D.F. Grishin, E.V. Kolyakina, V.V. Polyanskova, I.D. Grishin, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80,
No. 1, pp. 123!131.
AND POLYMERIC MATERIALS
Radical Copolymerization of N-Vinylpyrrolidone
with Methyl Methacrylate and Styrene
in the Presence of C-Phenyl-N-tert-butylnitrone
D. F. Grishin, E. V. Kolyakina, V. V. Polyanskova, and I. D. Grishin
Lobachevsky Research Institute of Chemistry, Nizhni Novgorod State University, Nizhni Novgorod, Russia
Received May 25, 2006
Abstract-The effect of C-phenyl-N-tert-butylnitrone on the features of radical copolymerization of N-vinyl-
pyrrolidone with methyl methacrylate and styrene was examined. Nitrone exerts virtually no effect on the
relative activities of the comonomers. At the same time, C-phenyl-N-tert-butylnitrone as a potential source of
nitroxyl radical makes it possible to prepare copolymers of N-vinylpyrrolidone with methyl methacrylate and
styrene to high conversions without gel effect, to control the molecular-weight characteristics of the copoly-
mers, and to prepare block copolymers.
Polyvinylpyrrolidone (PVP) and its copolymers
find diverse applications: from blood plasma substi-
tutes to propellant additives [1, 2].
The requirements to copolymers for medicobiologi-
cal purposes are more stringent than those to general-
purpose polymers. First, these copolymers should be
nontoxic in amounts ensuring the therapeutic effect.
Second, medicinal preparations should have a definite
molecular mass M and a narrow molecular-mass dis-
tribution (MMD), because the pharmacological effect
essentially depends on these parameters. In particular,
the molecular mass should not be too large to provide
spontaneous excretion. Finally, environmentally clean
methods for efficient commercial production of such
preparations should be developed.
Therefore, a search for efficient ways to control the
copolymerization of N-vinylpyrrolidone (VP) with
vinyl monomers is a key problem of N-vinylpyrroli-
The goal of this study was the development of pro-
cedures for preparing gradient copolymers of VP with
methyl methacrylate (MMA) and styrene (ST), and
also block copolymers derived from them with con-
trollable composition and molecular-mass characteris-
tics in the presence of C-phenyl-N-tert-butylnitrone
(PBN) as one of effective chain-terminating agents
under the conditions of radical initiation, maximally
similar to the industrial conditions .
C-Phenyl-N-tert-butylnitrone was prepared by the
procedure described in . The solvents, initiator
[azobis(isobutyronitrile), AIBN], and monomers (VP,
ST, MMA) were purified by standard procedures [73
9]; VP met the requirements of TU (Technical Specif-
ications) 6-09-2991378. The physicochemical con-
stants of all the compounds were in agreement with
published data. The (co)polymers were prepared from
the freshly distilled monomers. The samples were pre-
pared as follows: The monomer was placed in glass
ampules, degassed by threefold freezing3pumping3
thawing, and polymerized at a residual pressure of
1.3 Pa. The polymerization progress was monitored
gravimetrically, dilatometrically , and thermo-
When plotting the kinetic curves of the copolymer-
ization from thermographic data, we used the running
heats of copolymerization, calculated from the pub-
lished heats of homopolymerization of VP (64.3+
1.9 kJ mol
) , MMA (55.6+ 1.1 kJ mol
and ST (69.4+ 0.8 kJ mol
) , taking into account
the running compositions of the copolymers.
The copolymers obtained were purified to remove
residual initiator and monomers by twofold reprecipi-
tation from chloroform into hexane. The VP homo-
polymer was washed out with distilled water.