Chemistry Reference
In-Depth Information
since its intensity can be the one, that nanofiller particles aggregates size
exceeds 100 nm the value, which is assumed (though conditionally enough
[6]) as an upper dimensional limit for nanoparticle. In other words, the ag-
gregation process can result to the situation when primordially supposed
nanocomposite ceases to be one. Therefore, at present several methods
exist, which allow to suppress nanoparticles aggregation process [5, 7].
This also assumes the necessity of the nanoparticles aggregation process
quantitative analysis.
It is well known [1, 2], that in particulate-filled elastomeric nano-
composites (rubbers) nanofiller particles form linear spatial structures
(“chains”). At the same time in polymer composites, filled with disperse
microparticles (microcomposites) particles (aggregates of particles) of
filler form a fractal network, which defines polymer matrix structure (ana-
log of fractal lattice in computer simulation) [4]. This results to different
mechanisms of polymer matrix structure formation in micro and nano-
composites. If in the first filler particles (aggregates of particles) fractal
network availability results to “disturbance” of polymer matrix structure,
that is expressed in the increase of its fractal dimension
d
f
[4], then in case
of polymer nanocomposites at nanofiller contents change the value
d
f
is
not changed and equal to matrix polymer structure fractal dimension [3].
As it has been expected, the change of the composites of the indicated
classes structure formation mechanism change defines their properties, in
particular, reinforcement degree [11, 12]. Therefore, nanofiller structure
fractality strict proof and its dimension determination are necessary.
As it is known [13, 14], the scale effects in general are often found at
different materials mechanical properties study. The dependence of failure
stress on grain size for metals (Holl-Petsch formula) [15] or of effective
filling degree on filler particles size in case of polymer composites [16] are
examples of such effect. The strong dependence of elasticity modulus on
nanofiller particles diameter is observed for particulate-filled elastomeric
nanocomposites [5]. Therefore, it is necessary to elucidate the physical
grounds of nano- and micromechanical behavior scale effect for polymer
nanocomposites.
At present a disperse material wide list is known, which is able to
strengthen elastomeric polymer materials [5]. These materials are very di-
verse on their surface chemical constitution, but particles small size is a
common feature for them. On the basis of this observation the hypothesis
was offered, that any solid material would strengthen the rubber at the
