Agriculture Reference
In-Depth Information
Table 10.4.
Composition (in %) of natural cellulose fibres at 10% moisture content (Krässig
et al
., 1989).
Cotton
Jute
Flax
Hemp
Ramie
Sisal
Abaca
Cellulose
92.7
64.4
62.1
67.0
68.8
65.8
63.2
Hemicellulose
5.7
12.0
16.7
16.1
13.1
12.0
19.6
Pectin
0
0.2
1.8
0.8
1.9
0.8
0.5
Lignin
0
11.8
2.0
3.3
0.6
9.9
5.1
Water solubles
1.0
1.1
3.9
2.1
5.5
1.2
1.4
Wax
0.6
0.5
1.5
0.7
0.3
0.3
0
types of fibres contain more than 60% cellu-
lose, about 16% hemicellulose, but 0.8 resp.
1.8% pectin and 3.3 resp. 2.0% lignin.
Unfortunately, these fibres are often compared
as cellulosic fibres to cotton, which is a nearly
pure cellulose fibre containing neither pectin
nor lignin.
In practice, there are differences observed
between hemp and flax, for example, in
mechanical processing and in the production
of composites. For mechanical processing, dif-
ferent equipment has been established. Recent
work on the enzymatic treatment of hemp in
order to produce very fine fibre bundles has
shown that the processing parameters from,
for example, flax treatment cannot be trans-
ferred easily to hemp, since the structure of the
adhesive components between the fibres is dif-
ferent (Fischer
et al
., 2004a, 2006). This is a
foreseeable effect caused by the very specific
type of enzyme action, but these differences in
pectin structure even cause a different behav-
iour in chemical treatment, for example, in
EDTA solutions.
avivages on the surface were provided by
the company NAFGO GmbH, Neerstedt,
Germany, in 2001.
Sisal: the sisal (
•
Agave sisalana
Perr.
ex Engelm.) fibre bundles were provided by
the company NAFGO GmbH, Neerstedt,
Germany, in 2001.
Flax A: the flax (
•
Linum usitatissimum
L.)
fibre bundles (HL_04_01a) were provided
by the company Holstein Flachs GmbH,
Mielsdorf, Germany, in 2004. The flax
was grown near Mielsdorf in 2003 and
retted only briefly. The fibre bundles were
separated from the briefly retted long flax
during the scutching process in the sepa-
ration plant at Holstein Flachs GmbH.
Flax B: the flax (
•
Linum usitatissimum
L.)
fibre bundles (HL_04_01b) were provided
by the company Holstein Flachs GmbH,
Mielsdorf, Germany, in 2004. The flax was
grown near Mielsdorf in 2003. After har-
vesting, the stems were field retted and
baled. The fibre bundles were separated
from the very homogeneously retted long
flax during the scutching process in the
separation plant at Holstein Flachs GmbH.
Hemp: the hemp for the trials (
•
Cannabis
sativa
L.) was provided by the company
NAFGO GmbH, Neerstedt, Germany.
Quality management has been set up for
their products which allows tracing of the
fibre origin back to the grower. Through
fine-tuned growing, harvesting and separa-
tion management, constant fibre qualities
can be provided for technical applications.
The fibre bundles used are described in
detail in the following. The hemp variety
Fedora
was grown near Neerstedt
(Oldenburg region, Germany) in 2002 and
briefly field retted (A1000-value: 1.08 ±
0.13). The stems were coarsely by the
10.3 Properties of Natural and
Man-made Cellulose Fibres
In the following sections, the testing methods
described are applied exemplarily to typical nat-
ural fibres used as reinforcement for plastics.
10.3.1 Tested fibres
The following plant fibres have been used as
test specimens:
Jute: the jute (
•
Corchorus olitorius
L.)
fibre bundles (Schilgen) without any
