Chemistry Reference
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(
)
s
, adduced in Fig. 8.9 insertion, shows, this condi-
tion is also fulfilled. In other words, the Eq. (8.4) gives qualitative correct
description of the dependence s
f
(a) for the indicated polymer blends [14].
dependence
f
cr
FIGURE 8.9
The dependence of stable crack fractal dimension
D
cr
on PC content
C
PC
for
blends PAASO/PC. In insertion: the dependence
(
)
s
D
for samples with
a
=1 mm [14].
f
cr
In Ref. [4] it has been shown that
D
cr
increase from 1 up to 2 by its
very nature represents itself the transition from ideally sharp notch (
D
cr
=
1) to cavity (
D
cr
= 2), that is, the crack with blunted tip. Thus, the physical
significance of fractal model corresponds completely to the offered in Ref.
[2] treatment, namely, to the mechanism of notch blunting by local plastic
deformation zone.
Let us carry out the quantitative estimations according to the Eq. (8.4)
and compare them to the experimental dependences s
f
(
a
) by a fitting meth-
od. The comparison of the experimental and theoretical dependences of frac-
ture stress on the notch length (fitting was made by sf
f
values at
a
= 1.5 mm
one can see, the Eq. (8.4) describes well the experimental results and the ob-
served discrepancies (particularly at
a
= 0.5 mm) are due to the two follow-
ing reasons. Firstly, the calculation simplicity was not taken into account, a
