Chemistry Reference
In-Depth Information
)l.m.f150
f
FIGURE 12.2
The dependence of loosely packed matrix structure fractal dimension
d
on cross-linking density n
c
for epoxy polymers EP-2 (1) and EP-2-200 (2) [9].
It can be assumed that epoxy polymers structure loosely packed matrix
sustains the main load in indentor pressing process as the least stiff its com-
ponent. Its dimension
)l.m.f150
f
d
can be calculated according to the mixtures rule
[9]:
dd
=+-
,
cl
f
d
)l.m.f150
(1
f
)
(12.6)
f
f
cl
f
cl
where
c
φ
is nanoclusters fractal dimension, j
cl
is their relative fraction.
The value
cl
f
d
is accepted equal to the greatest for real solids dimension
(~2.95 [14]) in virtue of their dense package [10] and the value j
cl
can be
calculated with the help of the Eq. (1.12).
In Fig. 12.2, the dependence of
)l.m.f150
f
d
on cross-linking density n
c
increase
results to
)l.m.f150
f
d
reduction or loosely packed matrix structure loosening. This
effect should be reflected on the value
H
v
, which is confirmed by the data of
)l.m.f150
f
d
for the considered epoxy
polymers is adduced. As one can see, the linear correlation
H
v
(
)
)l.m.f150
f
is ob-
d
)l.m.f150
tained, showing
H
v
growth at
f
d
increase., that is, at loosely packed matrix
structure densification. The indicated correlation can be described analyti-
cally by the following empirical equation [9]:
( )
)l.m.f150
f
H
=
150
d
-
, MPa.
1
(12.7)
v
