Chemistry Reference
In-Depth Information
The calculated according to the indicated method dimensions
D
n
are
adduced in Table 6.2. As it follows from the data of this table, the values
D
n
for the studied nanocomposites are varied within the range of 1.10-
1.36, that is, they characterize more or less branched linear formations
(“chains”) of nanofiller particles (aggregates of particles) in elastomeric
nanocomposite structure. Let us remind that for particulate-filled compos-
ites polyhydroxiether/graphite the value
D
n
changes within the range of
~2.30-2.80 [4, 10], that is, for these materials filler particles network is a
bulk object, but not a linear one [36].
Another method of
D
n
experimental determination uses the so-called
“quadrates method” [43]. Its essence consists in the following. On the en-
larged nanocomposite microphotograph (see Fig. 6.2) a net of quadrates
with quadrate side size α
i
, changing from 4.5 up to 24 mm with constant
ratio α
i
+1
/α
i
=1.5, is applied and then quadrates number
N
i
, in to which
nanofiller particles hit (fully or partly), is counted up. Five arbitrary net
positions concerning microphotograph were chosen for each measure-
ment. If nanofiller particles network is a fractal, then the following rela-
tionship should be fulfilled [43]:
−
D
/2
,
(25)
N
~
i
i
α
.
In Fig. 6.6, the dependences of
N
i
on
S
i
in double logarithmic coor-
dinates for the three studied nanocomposites, corresponding to the Eq.
(25), is adduced. As one can see, these dependences are linear, that al-
lows to determine the value
D
n
from their slope. The determined accord-
ing to the Eq. (25) values
D
n
are also adduced in Table 6.2, from which
a good correspondence of dimensions
D
n
, obtained by the two described
above methods, follows (their average discrepancy makes up 2.1% after
these dimensions recalculation for three-dimensional space according to
the Eq. (24)).
where
S
i
is quadrate area, which is equal to
2
