Chemistry Reference
In-Depth Information
l
-
) is shown for PC and PAr, which
is linear and, hence, the Eq. (6.4) is valid at any rate for the considered
polymers. Since the Eq. (6.3), which was served as the basis for the Eq.
(6.4) receiving, was derived for fractal turbulent liquid, then the dependence
s
p
(
2
st
d
f
l
-
) linearity is the confirmation of turbulent character of amorphous
polymers cold flow.
As it is known [9], polymer viscosity at viscous flow depends on relative
fluctuation free volume
f
g
value, which can be estimated according to the Eq.
(2.19). In Fig. 6.3 the dependence of parameter
2
st
d
f
l
-
characterizing polymer
viscosity in cold flow region (the Eq. (6.3)) on
f
g
reciprocal value is adduced.
This dependence is linear and has the expected character -
f
g
increase results
to
2
st
d
f
2
st
-
d
l
decrease and, hence, to viscosity h reduction.
f
l
-
, characterizing fractal liquid viscosity,
on relative fluctuation free volume
f
g
for PC (1) and PAr (2) [7].
2
st
d
FIGURE 6.3
The dependence of parameter
f
In Ref. [8] the dependence of viscous stress t, which acts on solid body,
moving in fractal liquid with rate υ, was given:
--
,
(6.5)
1
d
1 21
d
t
~
L
f
f
where
L
is this solid body characteristic linear scale.
It is obvious, that stress t can be associated with is
p
and
L
, and as earlier,
with
l
st
and υ - with strain rate
e
. Hence, for the considered case the Eq.
(6.5) can be written as follows [7]:
