Agriculture Reference
In-Depth Information
18
16
14
12
10
8
6
4
2
0
hemp
30%
hemp
29% - 1%
S + 3% D
hemp
30% +
3% D
hemp
30% +
3% C
C and D: Compatibility components
S: Silane
Fig. 14.7.
Charpy impact test (without notch).
Tensile modulus
(M
p
a)
Charpy
(unnotched)
(kJ/m
2
)
Tensile resistance
(Mpa)
Flexion modulus
(Mpa)
VICAT (°C)
Heat deflection
test (HDT) (°C)
Resistance to
flexion (Mpa)
Fig. 14.8.
Synthesis diagram.
ISOTROPIC PROPERTIES
.
Glass fibres are oriented
with the flow of the material, according to
whether it is laminar or turbulent, adopting an
orientation that is parallel or perpendicular to
the flow. Properties are therefore anisotropic
according to the direction. In a complex piece
exhibiting variation in thickness and flow
direction when filled, the mechanical properties
of different parts will vary. Thickenings and
differential retractions will also be seen follow-
ing moulding.
Hemp fibres are not orientated with the
flow (Fig. 14.10). Hemp therefore produces
moulded plastic that possesses isotropic
mechanical properties. Additionally, the ran-
dom arrangement of hemp fibres also blocks
retractions in all directions, giving rise to the
following advantages:
•
Absence of thickenings, even in areas
where the compound is thickest. Inflating
agents become useless.
