Chemistry Reference
In-Depth Information
measure
p
1
characterizes a filler and
l
2
and
p
2
- a polymer matrix, respective-
ly. Such attribution is due to that fact that the section, characterized by index
1 is attributed to brittle fracture branch according to [58] and filler contents
increase raises composites brittleness. If in Cantor construction from initial
section of length 1 its middle part is removed, then two remaining thirds
length will be equal to ~0.667 [39]. Then this value follows to divide propor-
tionally to filler particles (aggregates of particles) size and distance between
filler neighboring particles surface, using their averaged values, and this will
be corresponded to scales
l
1
and
l
2
.
In the considered case this procedure can be concretized as follows [56].
Since for polymerization-filled compositions some appreciable filler par-
ticles aggregation is not observed in virtue of their preparation method fea-
tures, then for initial componors the distance between filler particles
b
p
is
determined as follows [51]:
1
/
2
€
‚
4
p
b
=
„
†
-
2
…
‡
d
,
(14.18)
p
p
3
j
„
…
n
where j
n
is filler volume contents,
d
p
its particles diameter.
For prepared by solid-phase extrusion samples it is assumed, that the
value
b
p
changes proportionally to extrusion draw ratio l.
The total componors fracture probability p in mechanical tests is obvi-
ously equal to one. Further this value is divided at the condition
p
=
p
1
+
p
2
as
ratio l for componor UHMPE-Al is shown. As one can see, the is
if2
growth
dependence s
if2
(l) type is due to interfacial boundaries polymer-filler fracture
at l > 5 [44]. Hence, at l
<
5 the fracture of polymer matrix and interfacial
boundary is equally probable (
p
1
=
p
2
= 0.5) and at l > 5 the second fracture
probability is higher (
p
1
>
p
2
). In addition it is assumed, that is
if2
at l > 5 is
equal to interfacial boundary strength sf
if
and for sf
if
= s
if2
= 0 the condition
p
1
=
p
will b obvious one. An intermediate values
p
2
are determined according
to the equation [55]:
0, 5
s
t
(14.19)
p
=
if
2
m
where t
m
is polymer matrix shear strength, equal to shear yield stress t
Y
[34]:
