Biomedical Engineering Reference
In-Depth Information
Table 9.7
Dynamic-mechanical characteristics of nanocomposites of
Y
1
Ba
2
Cu
3
O
6.97
with SHMPE
Weight ratio
SHMPE:
tan δ
(first
tan δ
(second
transition)
ceramic filler (
C) (
C) (
C)
T
c
transition)
T
α
T
=
150
8
T
=
100
8
T
=25
8
(
8
C)
(
8
C)
100:0
2.95
1.5
1.1
127 0.01
134 0.2
85:15
5.1
3.4
1.6
95
0.06
143 0.25
50:50
10.1
6.5
3.1
94
0.065
155 —
15:85
—
—
4.5
—
—
157 0.27
Table 9.8
Influence of filling rate on the temperature and enthalpy of melting of
the binder in SHMPE-Y
1
Ba
2
Cu
3
O
6.97
nanocomposites
Weight ratio
SHMPE:
Y
1
Ba
2
Cu
3
O
6.97
T
C)
(extrapolated onset
of DSC peak)
melt
(
8
ΔH
melt
per gram
of SHMPE (J/g)
Crystallinity (%)
100:0
134
115.0
39.1
85:15
143
116.5
39.7
50:50
155
122.5
41.7
15:85
157
123.5
42.0
binder at the interphase. However, based on the obtained results, the
dominant role of any of the factors mentioned cannot be definitely proven.
For this purpose, it is necessary to conduct thorough electron microscope
investigations of the nanocomposite samples.
Investigation of the structures of SC polymer-ceramic nanocomposites by
scanning electron microscopy has shown that, for both the amorphous and
the crystalline polymer matrices, a complete and uniform covering of the
ceramic grains by the binder occurs (Fig. 9.13 and Fig. 9.14). This indicates
a strong interaction at the polymer-ceramic interface. Electron microscope
investigations of polymer-ceramic nanocomposite samples obtained under
conditions of variable filling (Fig. 9.14) provide support for such an
assertion. Furthermore, fibril structures are observed in the nanocomposites
based on crystalline polymers (SHMPE, PP), independent of the SC ceramic
filler content (Fig. 9.13 and 9.14).
As seen in Fig. 9.14(a), in Y
1
Ba
2
Cu
3
O
6.97
:i-PP=85:15, singular fibrils
appear in the field of vision of the microscope. With an increase in ceramic
additive (Fig. 9.14(b) and (c)) the number of fibrils becomes significantly
higher. It should be noted that there are no such fibrilar structures in the
initial, unfilled semi-crystalline polymers (Fig. 9.15(a) and (b)). This
indicates that, during the formation of polymer-ceramic nanocomposites,
SC ceramics play a special role in the formation of the crystalline structure
of the polymeric matrix.
