Chemistry Reference
In-Depth Information
m
c
f
s
are fracture stress of composite and polymer matrix,
respectively,
K
s
is stress concentration coefficient. It is obvious, that since
b
m
increase results to
s
and
where
c
s
reduction, then this means interfacial adhesion level
decrease.
FIGURE 15.14
The dependences of reinforcement degree
E
p
/
E
l.m
on nanoclusters relative
fraction φ
cl
. 1÷3 - the theoretical dependences, corresponding to the Eqs. (15.15) ÷ (15.17),
accordingly; 4, 5 - the experimental data for PC within the temperature ranges: 293÷363K(4)
and 373÷413K(5) [43].
tr
s
for PC, taking into account sample cross-
section change in a deformation process, was used as
The true fracture stress
c
s
for natural nano-
composites, which can be determined according to the known formula:
(
)
tr
n
sse
=
1
+
,
15.19
f
f
f
where
m
s
is nominal (engineering) fracture stress, ε
f
is strain at fracture.
The value
f
s
, which is accepted equal to loosely packed matrix strength
m
l.m.
f
s
(φ
cl
) plotting, which proves to be linear, and by subsequent extrapolation of
it to φ
cl
= 0, that gives
l.m.
f
s
, was determined by graphic method, namely, by the dependence
l.m.
f
s
=40 MPa [43].
And at last, the value Ks can be determined with the help of the following
equation [39]:
