1070-4272/05/7806-1325 C 2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 8, 2005, pp. 1325!1328. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 8, 2005,
Original Russian Text Copyright + 2005 by Grishin, Valetova, Semenycheva, Il’ichev.
AND POLYMERIC MATERIALS
(Allylbenzene)tricarbonylchromium in Radical Polymerization
of Methyl Methacrylate and Styrene
D. F. Grishin, N. B. Valetova, L. L. Semenycheva, and I. S. Il’ichev
Research Institute of Chemistry, Lobachevsky Nizhni Novgorod State University, Nizhni Novgorod, Russia
Received December 9, 2004; in final form, April 2005
Abstract-The effect of (allylbenzene)tricarbonylchromium on the kinetic parameters of radical polymeriza-
tion of methyl methacrylate and styrene and on the molecular-weight characteristics of the resulting polymers
Control over the kinetic parameters of radical poly-
merization of vinyl monomers and over the molec-
ular-weight characteristics of the resulting polymers
under the conditions maximally similar to those of
their commercial synthesis is an urgent line of macro-
molecular chemistry [1, 2].
Nitroxyl radicals and their sources [3, 4] and
organometallic compounds [2, 4], including metal-
containing monomers [5, 6], are actively used today
to control the chain propagation in radical polymeriza-
tion processes. In particular, (a-methylstyrene)tricar-
bonylchromium affects the propagation step in poly-
merization of methyl methacrylate (MMA), styrene
(ST), and butyl acrylate . The controlling effect of
organochromium additives is due to their reaction
with initiator radicals and propagating macroradicals
to form relatively stable carbon-centered organometal-
lic radicals directly affecting the polymerization rate
and molecular weight of the polymers [5, 6].
In this study, we examined the polymerization
kinetics of MMA and ST and the molecular-weight
characteristics of the resulting polymers, as influenced
by addition of (allylbenzene)tricarbonylchromium
(ABC). It is known  that the polymerization of allyl
monomers has certain specific features associated with
the formation of stabilized allyl radicals in the course
of chain propagation. Therefore, it is of indubitable
interest to examine the effect exerted on elementary
steps of polymerization by compounds containing
simultaneously an allyl fragment and a stabilizing
(Allylbenzene)tricarbonylchromium was prepared
by the procedure described in ; its physicochemical
constants were consistent with published data. The
monomers were purified by standard procedures .
Commercial azobis(isobutyronitrile) (AIBN) used as
initiator was recrystallized from methanol. Nitroso-
durene used as spin trap was prepared according to
The polymerization of MMA and ST was per-
formed in evacuated temperature-controlled ampules.
The polymerization kinetics was monitored derivato-
graphically and thermographically . The polymers
formed were purified to remove residual monomers
by reprecipitation with hexane from a solution in ethyl
acetate under argon. The ABC content in double-
reprecipitated samples was determined from the chro-
mium content evaluated spectrophotometrically .
The molecular weight (MW) and molecular-weight
distribution (MWD) of poly(methyl methacrylate)
(PMMA) and polystyrene (PS) were estimated by gel
permeation chromatography (GPC)  using, respec-
tively, a single Phenogel column (Linear-2 Phenome-
nex) and a set of five Styrogel columns (Waters).
As detectors we used R-2301 (Knauer) and R-403
(Waters) differential refractometers. The eluents were
THF for PS and chloroform for PMMA.
The ESR specrta were taken on an AE-4700 com-
mercial radiospectrometer in special ampules. As
reference for magnetic field calibration we used Mn
ions incorporated in the MgO lattice.