Chemistry Reference
In-Depth Information
FIGURE 3.4
The relationship between experimental j
cl
and calculated according to the Eq.
(3.13)
c
φ
clusters relative fraction values for HDPE at testing temperatures 293 (1), 313 (2),
333 (3) and 353 K (4) [21].
T
As it is known [24], solid component fraction enhancement (namely such
component of amorphous phase a clusters are as regards devitrificated loose-
ly packed matrix) results to elastic constant growth. This enhancement can
be described quantitatively within the frameworks of percolation theory (see
the Eq. (3.7)), but in Ref. [21] the more simple variant was chosen, namely,
the polymers network connectivity model [25]. Then the elasticity modulus
E
value is determined as follows [25]:
h
a
x
c
,
(3.14)
E
=
S
where h
x
is network bonds formation probability (h
x
= j
cl
[24]), a
c
is a value
equivalent to Young's modulus for macromolecules elastic tension,
S
is mac-
romolecule cross-sectional area (for HDPE
S
= 14.7 Å
2
[26]).
As the estimations have shown [26], the theoretical values
E
(
E
T
) are a
little smaller than elasticity modulus experimental magnitudes. This assumes
one more structural factor availability, influencing on the value
E
. This fac-
tor can be traditional macromolecular binary hooking network, which can
