1070-4272/03/7611-1829$25.00C2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 11, 2003, pp. 1829!1831. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 11,
2003, pp. 1880!1882.
Original Russian Text Copyright + 2003 by Battalov, Leplyanin, Murinov.
AND POLYMERIC MATERIALS
Uranyl Sulfoxide Complexes as Photoinitiators
of Polymerization of Methyl Methacrylate
and Epoxy Acrylate Oligomers
E. M. Battalov, G. V. Leplyanin, and Yu. I. Murinov
Institute of Organic Chemistry, Ufa Scientific Center, Russian Academy of Sciences, Ufa,
Received April 16, 2003
Abstract-Photoinitiation activity of uranyl sulfoxide complexes in polymerization of methyl methacrylate
and epoxy acrylate derived from ED-16 and acrylic acid, and also the postirradiation effects in photopolymeri-
zation of these monomers were studied.
The behavior of uranyl salts in radical polymeriza-
tion is of interest. These compounds are inactive in
the thermal initiation of polymerization, but they are
fairly active photoinitiators . In this work, we
studied photopolymerization of methyl methacrylate
(MMA) initiated with uranyl sulfoxide complexes,
which are infinitely soluble in MMA monomer.
Methyl methacrylate was purified to remove the
stabilizer by the method described in . Uranyl sul-
foxide complexes were synthesized by the method of
. Polymerization was performed in the bulk at a
temperature controlled with +0.05oC accuracy. The
photopolymerization kinetics was studied dilatomer-
tically with molybdenum glass dilatometers. Epoxy
acrylate polymer was synthesized as in . A PRK-4
mercury lamp was used as a UV source; the distance
between the light source and reactor was 14 cm in
all experiments. The dynamic viscosity was measured
with a Rheotest 2.1 device. The spectra of the samples
were recorded on a Specord UV VIS spectrophotom-
Whyte and Melville were the first who studied
uranyl salts as photopolymerization initiators . They
found that, at low concentrations of uranyl sulfate, the
rate of photopolymerization of vinyl acetate and meth-
acrylic acid is proportional to the square root of the
salt concentration. Okamura and Motoyama  con-
firmed this dependence when studying vinyl acetate
photopolymerization activated with uranyl nitrate and
oxalate in the systems with water and acetic acid.
They observed reduction of U(VI) to U(IV) and as-
sumed the following reaction scheme taking into ac-
count the presence of water:
O 6 U
Simionescu et al.  studied photopolymerization
of acrylonitrile in the presence of uranyl salts and
found that the initiation activity decreases in the series
Polymerization occurs by radical mechanism, and
the polymer obtained has amorphous structure. The
subsequent studies  on using uranyl salts as
polymerization photoinitiators were aimed at compre-
hensive elucidation of the initiation mechanism.
The kinetic curves of MMA polymerization in the
presence of uranyl nitrate sulfoxide complex under
UV irradiation are shown in Fig. 1. As seen, the poly-
merization rate increases by a factor of approximately
Fig. 1. Kinetic curves of MMA polymerization at 50oC
(1) in the presence of 0.05 wt % UO
(DASO is diamyl sulfoxide) and (2) without additions.
(a) Conversion and (t) time; the same for Fig. 4.