Chemistry Reference
In-Depth Information
ponent content j
l.m.
. In this case the strain e in creep testing at constant stress
can be described according to the following relationship [7]:
j
e
~
t
l.m
.
,
(11.1)
where
t
is tests duration.
TABLE 11.1
The Structural and Mechanical Characteristics
of HDPE and Nanocomposites
on Its Basis [7]
Sample conventional sign
MMT contents,
mas. %
HDPE - MA
contents, mas. %
E,
GPa
A
-
-
0.58
B
1.0
-
0.50
C
5.0
5.0
0.89
MMT is
Na
+
- montmorillonite of mark cloisite 15A; HDPE - MA is HDPE, grafted by
maleic anhydride (compatibilizer);
E
is elasticity modulus.
Proceeding from the said above, for loosely packed matrix relative frac-
tion j
l.m.
determination the following equation can be written [9]:
j
l.m.
= 1 -
K
- j
cl
- (j
n
+ j
if
),
(11.2)
where
K
is crystallinity degree, jif
cl
, j
n
and j
if
are the relative fractions of
clusters, nanofiller (organoclay) and interfacial regions, respectively. It is
obvious, that the values jif
n
and j
if
are taken into account in the case of nano-
composites only [7].
K
=
0, 32
C
∞
1/ 3
,
(11.3)
where
C
∞
is the characteristic ratio, which is polymer chain statistical flex-
ibility indicator [11] and determined according to the Eq. (4.40).
For semicrystalline polymers the clusters relative fraction j
cl
is deter-
mined according to the following percolation relationship (analog of the Eq.
(4.66)) [8]:
j
cl
= 0.03(1 -
K
)(
T
m
-
T
)
0.55
,
(11.4)
where
T
m
and
T
are melting and testing temperatures, accordingly. For the
considered polymer materials
T
m
= 408 K [8].
