ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 7, pp. 1252!1257. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + B.B. Troitskii, L.V. Khokhlova, V.N. Denisova, M.A. Novikova, A.E. Golubev, A.V. Arapova, A.A. Zaitsev, 2008, published
in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 7, pp. 1171!1177.
AND POLYMERIC MATERIALS
Thermal Degradation of Composites of Poly(Methyl Methacrylate)
with Alkoxysilane Hydrolyzates
B. B. Troitskii, L. V. Khokhlova, V. N. Denisova, M. A. Novikova,
A. E. Golubev, A. V. Arapova, and A. A. Zaitsev
Razuvaev Institute of Organometallic Chemistry, Russian Academy of Sciences, Nizhni Novgorod, Russia
Received November 1, 2007
Abstract-Organic3inorganic composites of poly(methyl methacrylate) with alkoxysilane hydrolyzates form
transparent films. Their thermal and oxidative thermal degradation were studied by differential scanning
calorimetry and thermogravimetric analysis.
Poly(methyl methacrylate) (PMMA) is a large-
tonnage commercial product. Transparent PMMA
glasses are widely used in various fields of economy.
However, the heat resistance of PMMA is poor. Its
thermal degradation starts on heating above 150oC.
Modification of polymer properties with the aim
to improve the quality and prolong the service life
was and remains an urgent theoretical and applied
problem. Diverse methods are used today to inhibit
polymer degradation. These include choice of proper
processing conditions, addition of antioxidants or
oxidation inhibitors to the polymer, and control of
the supramolecular structure of polymeric materials.
Active efforts have been made recently to develop
polymeric nanocomposite materials. To prepare
nanocomposites, an ultrafine silica sol is introduced
into a polymer dispersion . Nanocomposites can
also be prepared by simultaneously performing poly-
merization of a monomer and hydrolysis of alkoxy-
silanes . Ivanchev et al.  reported on prepara-
tion of a nanocomposite material based on poly-
propylene (PP) by hydrolysis of alkoxysilanes
directly in a polymer matrix in the solid state or
in a melt.
It was interesting to examine the possibility of
preparing PMMA films filled with inorganic parti-
cles by introducing into a polymer solution hydro-
lyzates of various alkoxysilanes and to study
how the hydrolysis conditions and composition
of the blends affect the properties of the films
PMMA(I) samples were prepared in sealed am-
pules by bulk polymerization of MMA with various
concentrations of azobis(isobutyronitrile) (AIBN),
following the standard procedure . Before poly-
merization, MMA was purified by vacuum distilla-
tion and deoxygenated by threefold freezing3pump-
ing3thawing. Also, PMMA(II) samples were pre-
pared by bulk polymerization of MMA in air with-
out initiator under UV irradiation. Emulsion
PMMA was prepared as described in .
Tetraethoxysilane (TEOS), g-aminopropyltrieth-
oxysilane (APTEOS), and phenyltrimethoxysilane
(PTMOS) were purified by vacuum distillation.
Hydrolysis of siloxanes was performed at room
temperature in a flask. The mixture was stirred with
a magnetic stirrer at a rate of 500 rpm. Water was
added in an amount of 1 mol per each hydrolyzable
bond in alkoxysilane. Hydrochloric acid was used as
catalyst. The hydrolysis time was about 30 min. The
hydrolyzate was diluted with acetone in a volume
ratio of 1 : 20.
The solution of the hydrolyzate in acetone was
mixed with a solution of PMMA in methylene chlo-
ride and poured onto a Petri dish. The films ob-
tained after solvent evaporation were dried in a
vacuum oven at 60370oC to remove the solvent
completely. The film thickness was about 100 mm.
IR measurements were performed with an FSM
1201 IR Fourier spectrometer, and DSC measure-
ments, with a DSK 204 F1 Phoenix differential scan-