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Identification of fibers (Awad I. Said)
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Identification of fibers
* Vegetable fibers:
All vegetable fibers of cellulesic structure that is polymer of -glucose
The difference between them in the degree of crystallinity, the length, luster
and strength
Note: starch is polymer of -glucose
*Animal fibers:
They are polypeptide from amino acids and the difference come from the
type of amino acids and its order in the formation of the fibers.
*Synthetic fibers:
They are made from polymer (used as beads) by melting or dissolving it in
suitable solvent then passing this solution threw spinneret ((vessel (made
from metal resists the high temperature and high pressure) within it holes)).
Fibers
Natural Synthetic
Nylon, acetate , acrylic
Vegetable
(Cellulesic)
Animal (Protenic)
wool and silk
Mineral
Asbestos and glass
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Identification of fibers (Awad I. Said)
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1- fiber length
staple filament
Fiber of shorten length
In cm or inch units
All natural fiber except silk
Fibers of longer length in cm
or inch units
All synthetic fibers, silk
Synthetic fibers can be cut to be staple fibers
Any filament fiber is synthetic and not all staple fiber is
nature fiber
2- luster
bright dull
All synthetic yarn are bright
because the yarn is
composed of small no. of
fibers and there is nothing
break the light so; it appears
in bright appearance
All nature fiber except silk
because the large no. of fibers
and its spinning in the yarn
that make the no. of ends
threw the yarn is larger
Where these fiber ends breaks
the light causing
The dull appearance
The luster of the fibers can be decrease by some of
treatments as the addition of titanium dioxide (TiO2)
that breaks the light
The luster of the fibers can be increase by some
treatments as the mercerization of cotton.
Mercerization is the treatment of the fiber in alkaline
oln. for short time under tension.
Visual test
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Identification of fibers (Awad I. Said)
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3-Touch test:
Smooth & cool rough & warm
Cotton fibers give cold feeling because the thermal conductivity of cotton
that transfers the heat threw it. Wool give warm feeling because the lower thermal conductivity of wool.
Types of fibers
Flammable Self-extinguished Flame retardant
(aramide fibers)
Burning test
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Identification of fibers (Awad I. Said)
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Flammable fibers
fiber In flame Out flame odour ash
Cotton
ViscoseLinen
yellow continuous Burn paper Gray-blackEasley crashes
Wool (highsulpher content)
silk
burns Ceases ofburning
Burnt feather Gray-blackEasley crashes
Weighted silk
( silk soaked inSnCl4 & Na3PO3)
burns Ceases of
burning
Burnt feather Have skeleton of
as originalsample
nylon melts Ceases of
burning and melt
////////////// Black difficult to
crush
Microscopic
Section
Cross section Longitudinal
Section
Microscopic test
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Identification of fibers (Awad I. Said)
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Longitudinal-section
shape fiber
convolution Cotton
Mercerized cotton
Cross marking linen
Striations-Longitudinal marking
viscose
Scales wool
Tube line nylon
Textile
Pure fiber blend fiber
One shape more than one shape
*Solubility test carry on small part from the fibers
*Benefits of solubility test:A-identification the type of fibers and distinguishing between
them
Solubility test
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B-calculate the percentage of each type of pure fibers that make
the end fiber
*solubility test depend on choosing the correct solvent whichdissolve one type of the fibers
Fiber Solvent
Cellulose acetate Glacial acetic acid
Vinyon HH Chloroform
Vinyon N Dimethyle formamideNylon 90% phenol
Viscose Cuprammonium hydroxide
Carp ammonium Cuprammonium hydroxide
Cotton Cuprammonium hydroxide
Wool 20% bleach (NaClO)Vicara 20% bleach (NaClO)
Orlon Dimethyle formamide 55 C
Acrilan Conc. HNO3
Dacron Conc. HNO3
Distinguishing between fibers using solubility test:
1-Animal & vegetable fibers(a)- By boiled 5% lye soln. (caustic soda) (sodium hydroxide)
animal vegetable fibersdissolve Don
't effect
(b)- By acid (2% H2SO4 )A Drop of 2% H2SO4 is placed on the fabric that is placed between
two bottoms and pressed with hot iron
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Identification of fibers (Awad I. Said)
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animal vegetable fibers
Dont effect Show charring
2-cotton & linena-By 1% fachsin (magenta) soln.
By immersing the fabric (fiber) in this soln. And then washingit then immersing in ammonia soln.
Cotton linen
Is dyed by with arose-redcolour and disappear byammonia solu.
Is dyed by with arose-redthat remain after immersingin ammonia solu.
b-By immersing the sample in conc.H2SO4 for two minutes
Cotton linen
dissolve dont dissolve
c-by Herzbergs stainHerzbergs solu. Is prepared by addition to a solu. Of ZnCl2
(20 gm) in water (10 ml) asolu. Of kI (2.1 gm) and iodine (.1gm)
in water (5ml) is added where the sample is immersed in this solu.
Cotton linen
Is colored with reddish purple
colour
Is colored with purple
d-by caustic sodaBy immersing the sample in (10%) caustic soda
Cotton linen
Remain white Yellowish
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3-silk & woola-by conc. cold HCl
silk wool
dissolve swell
4-Rayons & acetatea-by 50% soln. of acetic acid
By immersing the sample in this solu.
Rayon (viscose) Acetate
does not dissolve dissolves
*all rayon dissolve in 60% H2SO4 or conc. HCl
b-By a soln. of equal amounts of H2SO4 conc. And iodine soln
In immersing the sample in the soln.
Rayon (viscose) AcetateColored in dark-blue color Yellow colour
5-acetate, triacetate & other fibersa-by immersing the sample in a soln. of 90% methylene
chloride 10% ethanol or methanol at R.T for one hour
Acetate and triacetate Other fibers
dissolve Dont effect
c- By immersing the sample in benzyl alcohol at (95 C) (200 F) for
one hour
Acetate triacetate
dissolve Dont effect
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6-nylons acetate & woola-By boiled sod. hydroxide
Nylons and acetate wool
Dont dissolve dissolve
b-by acetone
nylons acetate
Dont dissolve dissolve
* Nylon soluble in conc. Formic acid or phenol and cresol (Meta)
7- Polyester & nylon* Acetate, nylon and polyester dissolve in hot Meta cresol
a- by acetone
Nylon and polyester acetate
insoluble soluble
b- By conc. formic acid
Nylon polyester
soluble insoluble
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*By Rosaniline dye:
By immersing sample of cotton and linen in the dye for5second the sample colored with red-pink colour and thenimmersed in conc. NH4OH soln.
In case of cotton: decolonization of the pink colour is fasterthan in linen
Colour test
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TextilesA) Cellulosic fibers:
a) Natural : ex. Cotton, flax, jute, hempb) Manufactural : ex. Rayon(viscose)
O
H
OH
H
H
H
OHH
O
OH
n
Cellulose
O
H
OH
H
H
H
OHH
O
ONa
n
Sod. cellulosate
O
H
OH
H
H
H
OHH
O
O
n
Cellulose xanthate
O
H
OH
H
H
H
OHH
O
OH
n
Viscose(rayon)
NaOH
SNa
S
There is a type of cotton is called merecerized cotton that is prepared by immersing the
cotton fibers under tension in alkalin solution (NaOH 5%) for short time. Mercerizedcotton is characterized with the higher luster and strength. If the cotton fabric are not heldunder tension, the process is called slack mercerization and the obtained fabric is
characterized with high degree of elasticity.B) Protenic fibers : ex. Wool, silk, mohair, cashmer
H
N
CH2
OC
NH
CH
CO
HN
CH2
OC
NH
CH
CO
CH3 CH2OH
HN
CH2
OC
Febroin Structure in Silk
CH
NH
OC
CHR
HN
CO
HC
NH
OC
CHR
HN
CO
HC
CH2
Keratin Structure in Wool
R
CO
HN
CHR
OC
NH
HRC
CO
HN
CH
OC
NH
HRC
CO
HN
CH2
COO
CH2
CH2
CH2
H2C
NH3
S
S
CH2
CH2
H-BondSalt linkage
Cystine linkage
