Agriculture Reference
In-Depth Information
property, especially by comparing the data of
different authors, is often difficult because
fibres with unknown history and different
testing methods have been used. For this rea-
son, the following sections focus on making
the various properties of different fibres com-
parable by using identical samples and testing
methods. Furthermore, explanations of the
economic significance and the suitability as
well as the description of testing methods
should help the reader in choosing test meth-
ods for measuring fibres.
in composite materials, length, fineness and
mechanical properties like Young's modulus
(stiffness) and the strength of the fibre influence
greatly the mechanical performance of the
reinforced plastics (Kaw, 1997). To predict the
properties of composite materials, several ana-
lytical and semi-analytical models for laminates,
micromechanical models and failure criteria
have been developed. Apart from the mechan-
ical properties, these models require knowl-
edge of the fibre morphology. For a numerical
simulation, knowledge of the length of the
fibres, their fineness and their mechanical data
is essential.
10.2
Aspects of Fibre Quality
Management
Colour
In retting control and in trade, colour plays an
important role. It can be measured objectively
with a colour system like the CIE (L*a*b*) colour
system.
10.2.1 Economic and technical
significance of natural fibre tests
For continuous production, it is important that
the supplied fibres have been tested systemati-
cally, allowing a reliable determination of devi-
ations occurring in the key properties. The
main fibre quality characteristics relevant for
the use of natural fibres in the reinforcement of
plastics are shown in Table 10.1.
Chemical composition,
accompanying substances
For car-interior applications, the chemical
composition of the fibres and the resulting
properties such as fogging and odour have to
be taken into account. The share of volatile
components determines whether or not the
materials will be approved for use in vehicle
construction. The same holds true for the use
interiors, which is ruled out if there is any
intensive or unpleasant odour.
Morphological properties
and mechanical data
For use in textiles, the quality of the yarn is
determined by the short fibre content, fine-
ness, fibre-fibre friction and strength. For use
Table 10.1.
Key fibre properties and their industrial significance.
Industrial relevance/application
example
Category
Fibre property
Morphological properties
Fineness
Processing
Length
Simulation
Mechanical behaviour
Mechanical data
Strength (Young's modulus)
Colour
LAB or CIE values
Design application
Chemical composition,
accompanying substances
Fogging behaviour
Automotive industry
Rail vehicle construction
Odour emission
Car interior applications
Harvesting, mechanical
separation
Wooden stem parts
Mechanical behaviour,
processing, design
Degree of retting
Mechanical behaviour, processing
