Chemistry Reference
In-Depth Information
acrylonitrile fibre-production parameters for further treatment by metalli-
sation to obtain electroconductive polyacrylonitrile.
11.2.2 Metallisation of different types of fibres
Metallisation of fibres is not only a physical process determined by absorp-
tion capacity of the fibres for the metal and diffusion capacity of the metal
in the fibre structure, but also depends on chemical parameters such as
chemical structure of the fibres, presence of functional groups, reactivity of
the fibre and the metal, oxidation state of the metal and the presence, neces-
sity and reactivity of supporting chemicals (e.g. reducing agent). Therefore,
it was necessary first to study metallisation at different types of fibres in
order to investigate which structure is most useful for further research. In
this respect, viscose, cotton, natural silk and polyacrylonitrile fibres were
investigated because of their different structure and properties and their
availability in the New Independent States of the former Soviet Union
(Uzbekistan, Kazakhstan, Kyrgyzstan).
Metallisation of these fibres was performed in a single-step process by
immersing the fibre for both 5 and 15 min in a bath containing either
0.3 mol l
-1
sodium dithionite and 0.06 mol l
-1
NiCl
2
or 1.5 mol l
-1
rongalite and
0.5 mol l
-1
NiCl
2
at both 283 K and 363 K, respectively. Analysis of the fibres
obtained was carried out according to methods described in the literature,
14
together with the methods explained below, with the results presented in
Table 11.1.
•The content of Ni and NiS (and similar for Co species) present in the
fibre was determined in three steps:
Table 11.1
Nickel absorption and reduction by sodium dithionite and rongalite
for different types of fibres and their electroconductive capacity
Fibre type
Reducing agent: sodium
Reducing agent: rongalite
dithionite
Amount of Ni,
Specific
Amount of Ni,
Specific
ww%
electrical
ww%
electrical
resistance
(
W
m)
resistance
(
W
m)
Ni
t
Ni
S
Ni
M
Ni
t
Ni
S
Ni
M
10
7
10
7
Viscose
3.92
3.11
0.81
4.90
4.00
0.90
10
7
10
7
Cotton
2.28
2.00
0.28
3.68
2.84
0.84
Silk
4.30
3.12
1.18
1.3
4.60
3.30
2.30
1.0
2
¥
10
-
4
2
¥
10
-
4
PAN, fresh
5.10
1.37
3.73
5.80
2.30
3.50
5
¥
10
-
3
7
¥
10
-
3
PAN, thermofix
4.62
2.12
2.50
4.80
2.60
2.20
