Chemistry Reference
In-Depth Information
Table 11.3
Physico-mechanical properties of metallised PAN fibres as a
function of metal content for freshly formed PAN fibres
ww%
M
t
in
Linear density
Strength
Elongation
Preservation of
PAN fibre
(tex)
(g/tex)
(%)
strength (%)
Nickel-containing PAN fibres
0
0.354
25.2
33.3
NA
0.31
0.371
23.5
37.0
93.4
0.70
0.355
26.3
35.0
104.0
1.20
0.372
22.3
36.0
88.6
1.52
0.278
24.6
38.0
97.8
Cobalt-containing PAN fibres
0
0.354
25.2
33.3
NA
0.33
0.349
24.8
35.2
98.5
0.69
0.363
26.5
32.6
105.0
1.14
0.378
23.4
40.4
93.5
1.44
0.440
21.7
44.4
86.0
11.3, from which it can be seen that the physico-mechanical properties of
the fibres obtained are only weakly dependent on the amount of nickel or
cobalt taken up in their structure. A remarkable fact is that for a metal
content of about 0.7%, the values for linear density, strength, elongation
and preservation of strength are only slightly different between the two
metals investigated.
The unchanged mechanical properties of the PAN fibre before and after
metallisation indicate that swelling of the fibre is limited, which is confirmed
by microscope images at cross-sections of a PAN fibre, a NiCl
2
-treated PAN
fibre and a NiCl
2
-treated PAN fibre after thermofixation. These experiments
were repeated with Fe(II) and showed an important swelling behaviour of
the fibre resulting in large shifts of the physico-chemical properties. These
properties were so disadvantageous that, in combination with the limited
conductivity of Fe(II)-treated PAN fibres, they were not taken into consid-
eration for further research.
The fibres produced according to the above procedure, which resulted in
the data presented in Table 11.3, were further subjected to heat treatment.
These fibres were exposed to 473 K for approximately 2 h, and again the
physico-mechanical properties were investigated (Table 11.4). It can be seen
that an important decrease of the mechanical parameters is obtained;
however, this reduction is not due to the fact that these fibres are metallised,
because the unmetallised PAN fibres showed a similar shift in physico-
mechanical properties.
