Introduction to fibre

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Introduction to fibre textile technology
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What is fibre ?
Fibre Units of matter characterised by
flexibility, fineness and a high ratio of
length to thickness. (defined by the Textile
Institute)
The length/diameter ratio should be at least
10001
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General fibre classification
Natural fibres Cellulosic Protein Mineral Cotto
n(seed hair) Wool Asbestos Flax
(bast) Silk Jute (bast) Mohair Sisal
(leaf) Cashmere Ramie (bast)
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Typical cross sectional shapes and fiber contour
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Man-made fibres Regenerated Modified
Synthetic Mineral Viscose Cellulose
Polyamide Glass rayon diacetate
Polyester Steel Cellulose Polyacrylic
Carbon triacetate Polyolefin
Polyvinyl
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Fibre Properties To analyse a fabric to
predict its performance, one usually starts
with the fibre content.   ?The external
structure ?The chemical composition ?The
internal structure
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? External structure or morphology  1. Length
Filament, Staple, Filament tow
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2. Fineness (diameter, size, denier)
Diameter range (microns) Diameter range (microns)
Cotton 16-20 microns
Flax 12-16 microns
Wool 10-50 microns
Silk 11-12 microns
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Denier the weight in grams of 9,000 metres of
yarn (or fibre) Decitex the weight in grams of
10,000 metres 1 decitex 0.9 denier 1 tex 10
decitex 1000 millitex
Q. If 5000 meters of a fibre has a mass of 0.6
grams then the linear density is tex.
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3. Cross - sectional shape (see
figure) Luster, body, texture or feel of a
fabric Different between natural fibre and
m.m. fibre
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4. Surface contour important to the hand and
texture Luster the gloss or shine that a
fabric posses. It depends on amount of light
reflect on fibres. 
Specular
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Lustrous fibres
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5. Fibre parts Natural fibres (except silk)
cuticle or skin, inner area, central
core Manmade fibre skin and solid core
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 ? Chemical composition Type Characteristic
linkage Polyamide - NH CO - Protein, wool,
silk - NH CO - Polyester - CO O
Cellulose - O C
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• Internal structure or molecular arrangement
• Degree of polymerisation
• - Molecular weight
• - Molecular arrangement
• oriented, amorphous, crystalline

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(Stretching or drawing MM. Fibre)   The amount
of crystallinity and orientation relates to
the physical prop. such as strength,
elongation, moisture absorption and abrasion
resistance. (See Fibre property charts)
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- Refractive index A measure of how light is
bent as it passes through the surface of a
material.
Reflactive indices in fibre
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Tensile strength, stress, strain  In engineering
term, stress load area of
cross section Specific tensile stress
load

mass per unit length
(Ntex -1 or mNtex -1)
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Tensile strain elongation original
length   Extension () tensile strain x 100
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Stress/strain curves The values for particular
textile depend on - Type of specimen (single
fibres, yarn, fabric) - The dimensions of the
sample - The atmospheric conditions in the
laboratory - Speed of testing machine
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Typical stressstrain curve for a fibre
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Modulus (Tan ?) Yield point In this area
small changes in load produce large changes in
length Elasticity Elastic recovery
recovered extension total extension
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Fibres and moisture Relative humidity (R.H.) is
the amount of water vapour in air. R.H. ()
percentage of the maximum amount that the air can
hold at the particular temperature.
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Moisture content () mass of moisture in the
sample x 100 mass of the undried sample
Moisture regain () mass of moisture in the
sample x 100 mass of the dry sample