Chemistry Reference
In-Depth Information
temperatures range
T
= 353 ÷ 453 K. At the same time a good linear rela-
tionship was obtained (Fig. 3.1) for quasistatic tension tests results in the
same temperatures range. This distinction is due to tests temporal scale sharp
reduction at impact loading and, as consequence, to mechanical vitrification
of the devitrificated loosely packed matrix part, that results to
G
growth [7].
The relationship between shear modulus G and parameter
(
-
-D
for
)
f
d
1
φ
FIGURE 3.1
cl
PASF in case of impact (1) and quasistatic tension (2) tests [7].
As it is known [12], the elasticity modulus
E
value in polymers impact
tests grows at testing temporal scale decrease (at brittle fracture - time up to
failure
t
f
) and can be described according to the empirical relationship [12]:
-
m
E
=
E
t
,
(3.8)
0
f
where
E
0
is “unit” modulus, that is, the value
E
at
t
f
= 1 in the chosen tempo-
ral scale,
m
is empirical exponent, characterizing relaxation processes com-
pleteness degree.
The description difficulty of
E
behavior within the frameworks of the Eq.
(3.8) contains in two empirical constants (
E
0
and
m
) availability, which can
also change their values discontinuously [7]. Therefore, the authors of Refs.
