Agriculture Reference
In-Depth Information
7000
6000
5000
4000
3000
2000
R
1000
0
PEhd
(Inject)
PEhd
(Inject)
PEhd
(Extr)
PPh
PPc
Polymer + 30% Hemp
Unreinforced polymer
R = retted hemp
Fig. 14.5. Tensile modulus of reinforced and non-reinforced polymers.
5000
Polymer + 30% Hemp
Unreinforced polymer
R = retted hemp
4500
4000
3500
3000
2500
2000
1500
R
1000
500
0
PEhd
(Inject)
PEhd
(Inject)
PEhd
(Extr)
PPh
PPc
Fig. 14.6. Flexion modulus of reinforced and non-reinforced polymers.
completely deformed under its own weight.
PP's thermal performance increases from
90°C to 145°C when it is mixed with 30%
hemp. The Vica t 2 point of PVC similarly
is increased by 5°C under the same
conditions.
For a copolymer of PP, we arrive at the
properties shown in Fig. 14.8.
the water is redistributed (Fig. 14.9). The
cycle is reproduced without affecting the
compound.
These properties can be used in the cre-
ation of active objects. We have demon-
strated that a storage pallet made from
high-density PE reinforced with 20% hemp
fibre possesses, in addition to its interesting
mechanical properties, the ability to store a
bactericidal liquid. It can take up this liquid in
the space of a few hours and then release it
slowly over a period of 8 months, thus killing
any bacteria coming into contact with the
pallet. Such materials can therefore be
reinforced mechanically and used in such a
way that they control smells and humidity.
They can also be used to produce particular
surface properties (e.g. lubricated and anti-
static surfaces).
WATER ABSORPTION . A well-known property of
natural fibres is their ability to absorb water.
Fibres possess a porous structure and can,
when incorporated within a polymer, absorb
liquids by capillary action. A piece of compos-
ite reinforced with 30% natural fibre can
therefore absorb a significant amount of water
(approximately 7%) when submerged. If, once
saturated, the composite is left to air dry under
normal temperature and humidity conditions,
 
 
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