ISSN 1070-4272, Russian Journal of Applied Chemistry, 2007, Vol. 80, No. 12, pp. 2119 !2123. + Pleiades Publishing, Ltd., 2007.
Original Russian Text + S.A. Trifonov, A.A. Malygin, A.K. D’yakova, J.-M. Lopez-Cuesta, N. Cinausero, 2007, published in Zhurnal Prikladnoi Khimii,
2007, Vol. 80, No. 12, pp. 2041!2045.
AND POLYMERIC MATERIALS
Thermal Transformations of a Polymeric Composite
Consisting of Poly(Methyl Methacrylate)
Nanodispersed Aluminum Oxide
S. A. Trifonov, A. A. Malygin, A. K. D’yakova, J.-M. Lopez-Cuesta, and N. Cinausero
St. Petersburg State Institute of Technology (Technical University), St. Petersburg, Russia
Centre des Materiaux de Grande Diffusion, Ecole des Mines d’Ales, France
Received May 31, 2007
Abstract-Thermal-oxidative properties of polymeric composites based on poly(methyl methacrylate),
containing surface-modified nanosized aluminum oxide as filler, were examined. The possibility of chemical
grafting to the Al
surface of phosphorus-containing groups to decrease the combustibility of filled poly-
meric composites was examined by IR spectroscopy.
Inorganic fillers are widely used to improve the per-
formance characteristics of polymeric composite ma-
terials ; they bring about a wide spectrum of inter-
actions at the polymer3filler interface, thereby sub-
stantially affecting the mechanical and physicochem-
ical, in particular, thermal-oxidative, properties of
filled polymer system as a whole. The nature of these
interactions is governed to a significant extent by
the chemical composition of the filler surface .
Since recently, the focus of the special attention of
researchers has been on highly dispersed (nanosized)
fillers. They have a large specific surface area and
exhibit enhanced reactivity toward polymer matrix,
thereby promoting formation of chemical bonds limit-
ing the mobility of various kinetic units of the poly-
mer. Introduction of highly disperse fillers can change
the packing density of the polymer chains, as well as
the conformation and orientation of the segments oc-
curring at the polymer3filler interface [3, 4].
Of special interest is chemical modification of fil-
lers, considerably expanding the spectrum of their
functions in composite materials. Directed modifica-
tion of the filler surface aimed to produce groups
capable of forming strong chemical bonds with macro-
molecules or increasing the resistance of polymers to
thermal and thermal-oxidative degradation appreciably
enhances the stability of filled composite materials
[2, 5]. However, various chemical techniques applied
to this end should not substantially affect the particle
size of highly dispersed fillers and cause agglomera-
tion of nanosize particles.
Among the promising ways of chemical modifica-
tion of solid surfaces is molecular layer deposition
(MLD) [6, 7]. With MLD method, the entire surface
being activated is uniformly coated with the additives
introduced, which form strong chemical bonds with
the surface; the composition can be precisely set at
the molecular level, and multicomponent structures
with prescribed ratio and mutual position of elements
can be formed.
We examined here the thermochemical transforma-
tions of a polymeric composite material based on
poly(methyl methacrylate) (PMMA), filled with nano-
dispersed aluminum oxide and products of its sur-
face modification with phosphorus-containing groups
by the MLD method.
As filler for PMMA served Aeroxide AluC (Degus-
sa) nanodispersed aluminum oxide. Its specific sur-
face area estimated from low-temperature nitrogen
adsorption on a SORBIR N.4.1 instrument was
100 + 3m
; the average particle size was 13 nm.
Samples of the composite materials were prepared by
mixing crushed granules of Altuglas V 825T PMMA