Agriculture Reference
In-Depth Information
fibres of hemp and cellulose have a length
varying between approximately 5 and 60 mm.
They have a density of 1.4 g/cc.
It also presents a number of specific
advantages that suggest it will be developed in
preference to other plants:
Hemp prices are stable and unlike other
fibre-producing plants such as flax are not
susceptible to changes in fashion.
The hemp plant is not destroyed by parasites
14.3.2 Hemp
Hemp provides fibres with properties com-
parable to those of other technical fibres
(Table 14.2).
or disease and therefore does not require any
chemical treatment (insecticides, pesticides)
and its need for nitrogen fertilizers is low.
Hemp is less fussy about the ground it is
grown on, making it easy to expand its culti-
vation in response to increases in demand.
Hemp is a beneficial plant for other crops as
20%
22%
it smothers out all weeds and thereby avoids
the need to use chemical weedkillers.
In addition to the use of hemp fibre in the
43%
15%
papermaking industry, hemp can be used
to produce a number of co-products
(hurds, hemp seed and powder) that there-
fore provide added value.
The cultivation and transformation of
Electricité
Automobile
Pièces Techniques
Divers
hemp are well practised in the EU.
Fig. 14.3. Market for reinforced plastics.
Table 14.1. Content of vegetable fibres, showing percentage of four principal components: cellulose,
hemicelluloses, pectin and lignin.
Fibres
Cellulose (%)
Hemicelluloses (%)
Pectin (%)
Lignin (%)
Cotton
92
6.0
Flax
71.2
18.6
2.3
2.2
Hemp
76
11.5
1.3
3.2
Jute
71
13.3
0.2
13.1
Sisal
75
21.8
0.9
11
Abaca
70
21.7
0.6
5.7
Kenaf
61
20.4
11
Wood
50
24.0
26
Table 14.2. Tensile properties of fibres.
Fibre properties under tension
Nature
Density (g/cm 3 )
Resistance (gpa)
Lengthening (%)
Module (gpa)
Glass
2.54
1.4-2.6
2
75
Wood
1.54
0.14-1.5
20-40
Flax
0.3-0.96
1.5-4.0
27-80
Hemp
1.4-1.5
0.5-1.04
1.0-6.0
32-70
Jute
0.4-0.8
0.8-2.0
13-26.5
Viscose
1.5
0.31
11
Note : According to FINK, WEIGEL IAP Potsdam - GEIGER ICT Pfi nztal - BUSCH IWM Halle.
 
 
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