Identification of textile fibers.

ASSIGNMENT ON
IDENTIFICATION OF TEXTI LE FIBERS

 A number of methods are available for characterization of
the structural, physical, and chemical properties of fibers.
Various methods are used for fiber identification like
microscopic methods, solubility, heating and burning method,
density and staining etc. End-use property characterization
methods often involve use of laboratory techniques which are
adapted to simulate actual conditions of average wear on the
textile or that can predict performance in end-use.

TYPES OF TEST
The Non technical Test
• FEELING TEST
• BURNING TEST
The Technical Test
• MICROSCOPIC TEST
• CHEMICAL TEST

TESTS FOR IDENTIFICATION
 Handle/Feel Test
 Visual Examination
 Burning test
 Twist on Drying
 Floatation Test
 Microscopic analysis
 Chemical Analysis

REQUIREMENTS FOR
TESTS
Preparation of test specimen
Apparatus for microscopic examination
Reagents used for chemical tests
Other tools and equipment

THE NON-TECHNICAL TESTS
Feeling test
Burning test

FEELING TEST
 The feeling test requires perception if it is
to be of any value.
Skilled perception is acquired only after
handling many different fabrics over a period
of time.
Limitations of this test become apparent
when examining and comparing fabrics of
different fiber content.

BURNING TEST
 To recognize the composition of fabrics by the
burning test ,the sample of fiber, yarn of fabric should
be moved slowly towards a small flame and the
reaction to heat carefully observed .One end of the
sample should be put directly into flame to determine
its burning rate and characteristics. The burning odour
should be noted and the characteristics of the ash such
as amount ,form, hardness and color should be
examined

IDENTIFICATION OF FIBRES
THROUGH BURNING TEST
Cotton :
• When ignited it burns with a steady flame and
smells like burning leaves. The ash lefties easily
crumbled. Small samples of burning cotton can be
blown out as you would a candle.
Linen:
• Linen takes longer to ignite. The fabric closest
to the ash is very brittle. Linen is easily
extinguished by blowing on it as you would a
candle.

Silk:
• It is a protein fiber and usually burns readily, not
necessarily with a steady flame, and smells like
burning hair. The ash is easily crumbled. Silk
samples are not as easily extinguished as cotton
or linen.
Wool
• It is also a protein fiber but is harder to ignite
than silk as the individual "hair" fibers are
shorter than silk and the weave of the fabrics is
generally looser than with silk. The flame is
steady but more difficult to keep burning. The
smell of burning wool is like burning hair.

MAN MADE FIBERS
Acetate:
• Acetate burns readily with a flickering flame that
cannot be easily extinguished. The burning cellulose
drips and leaves a hard ash. The smell is similar to
burning wood chips.
Acrylic:
• Acrylics burn readily due to the fiber content and the
lofty, air filled pockets. A match dropped on an acrylic
blanket can ignite the fabric which will burn rapidly
unless extinguished. The ash is hard. The smell is
acrid or harsh

 Nylon:
• Nylon melts and then burns rapidly if the flame
remains on the melted fiber. If i can keep the
flame on the melting nylon, it smells like burning
plastic.
Polyester:
• Polyester melts and burns at the same time, the
melting, burning ash can bond quickly to any
surface it drips on including skin. The smoke
from polyester is black with a sweetish smell.
The extinguished ash is hard.

Rayon:
• It is a regenerated cellulose fiber
which is almost pure cellulose.
Rayon burns rapidly and leaves
only a slight ash. The burning
smell is close to burning leaves

LIMITATION OF BURNING TEST
It is apparent that many fibers have
similar burning reactions that might
cause doubt and occasional confusion.

TECHNICAL TESTS
 There are certain technical tests performed for identifying
various fibers. These tests require high technology laboratory
equipment and are much more reliable than the non technical
fiber tests.
 Technical tests require high skilled personnel and
technical know how of handling chemicals and their accurate
analysis. These tests are very valuable for those fabrics that
are a blend of different yarns and also have certain special
properties including flame retardance etc.

TYPES OF TECHNICAL TEST
Microscopic test
Chemical test

MICROSCOPIC TEST
 Microscopic test is a technical test that involves identifying
the fabric with the help of a microscope with a magnification
of minimum 100 power.
 The test can easily distinguish between fibers.
 The test identifies the natural fibers more easily as
compared to man made ones.
 Synthetic fibers are very similar in appearance and the
increase in the number of varieties, makes it a little tough to
distinguish the fibers even under a microscope

MICROSCOPIC T EST FOR NATURAL F I BERS
 COTTON:
• It is a single elongated cell. Under the microscope, it
resembles a collapsed, spirally twisted tube with a
rough surface.
• The thin cell wall of the fiber has from 200 to
400convolutions per inch.
 LINEN:
• Under the microscope, the hair like flax fiber
shows several sided cylindrical filaments with fine
pointed ends.
• The fiber somewhat resembles a straight,
smooth.

 WOOL:
• Under the microscope , wool’s cross section
shows three layers- epidermis, cortex and the
medulla.
SILK:
• It appears somewhat elliptical and triangular in
cross section when we see under the microscope.
• It is composed of fibroin, consisting of two
filaments, called brin which is held together by
sericin.

MICROSCOPIC T EST FOR
MANMADEF I BERS
 RAYONS:
• Rayon fibers have a glasslike luster under
the microscope and appear to have a
uniform diameter when viewed longitudinally.
ACETATE:
• The cross sectional view has a bulbous or
multi global appearance with indentations.
• These indentations appear as occasional
markings.

 NYLON:
• The basic microscopic appearance is generally
fine ,round, smooth, and translucent.
• It is also produced in multilobal cross-sectional
types.
POLYESTERS:
• Generally, polyester fibers are smooth and
straight and the cross-section is round.
• This general characteristics may be altered to
achieve certain characteristics.

 ACRYLICS: The methods of manufacturing of the acrylic
fibers differ, the appearances vary accordingly.
 ACRILAN ACRYLIC: It has a bean-shaped cross section,
its longitudinal appearance is straight and smooth.
 ORLON ACRYLIC: It has a flat, nut-shaped cross section.
 CRESLAN ACRYLIC: It has an almost round cross section.
 MOD ACRYLICS: it is of two types verel mod acrylic and
SEF mod acrylic.

 SPANDEX: Spandex fibers are unique in appearance, they
appear to be groups of fibers fused together.
 GLASS: The fiber is smooth, round, translucent, highly
lustrous, and quite flexible.
Asbestos fiber: This method is for the analysis of asbestos
in air by Phase Contrast Microscopy. Results are reported as fibers
per cubic centimeter and depend on the volume of air sampled. PCM
analysis is not asbestos fiber specific and will count all fibers meeting
the methods criteria for fiber determination.

CHEMICAL TESTS
 Chemical tests are another technical means of
identifying fibers. But chemical tests are not intended
for the general consumers.
 Different types of chemical tests are under taken to
establish the identity of the fibers used.
 These tests give accurate and precise analysis.
 The tests are conducted in research laboratories.

TYPES OF CHEMICAL TEST
 Stain Test:
• Also known as the Double Barrel Fiber
Identification(DBFI), the test is based on the
theory that each fiber has its own distinct
two- color reaction when treated with stain. A
fiber will turn to a particular color in the
presence of dilute acetic acid and to some
other specific color when stained in the
presence of a mild alkali.

 Solvent Test:
• The test involves treating the fibers in
certain solvents for identifying them. The
technical test is becoming difficult to
conduct as most of the manufactured
fibers and their blends are chemically
similar. There is no individual chemical or
solvent test for separating or identifying
the fibers in combinations.

 Distinguishing animal from vegetable fibers with an acid :
• As strong alkali destroy animal substances, a 5%of
soda lye solution in water can be used to eliminate
wool and silk fibers from a sample that contains a
mixture of fiber. The vegetable fibers will not be
affected by this solution.
 Distinguishing vegetable from animal fibers with an acid
• As dilute acid destroy vegetable fibers, a 2%sulphuric
acid solution can be used. A drop of solution is placed
on the sample, which is then pressed with a hot iron.
The spotted area will become charred if the sample is
cotton linen or rayon.

 DISTINGUISHING SILK FROM WOOL:
• The use of concentrated cold hydrochloric
acid will dissolve the silk and the wool fiber
swells.
DISTINGUISHING NYLON FROM OTHER FIBRES:
• If the fabric is thought to contain nylon, the
fabric may be immersed in a boiling solution
of sodium hydroxide. The nylon is insoluble in
such a solution

 DISTINGUISHING POLYESTERS
FROMOTHER FIBRES:
• Polyester is soluble in hot meta cresol; however ,unlike
acetate it is not soluble in acetone, and unlike nylon it is not
soluble in concentrated formic acid.
DISTINGUISHING ACRYLICS FROMOTHER
FIBRES:
• Acrylic fibers will dissolve in 70 percent solution of
ammonium thiocyanate at 130 degree Celsius but the other
fibers will not.

 DISTINGUISHING LINEN FROM COTTON
• Cotton and linen are immersed in a 1% solution of
fuchsine in alcohol to give red rose color. Later ,they
are washed and immersed into ammonia, linen retains
the red coloration but cotton does not.
DISTINGUISHING GLASS FIBERS FROM
OTHERFIBRES:
• There are two specific solvents for quick identification
of glass fibers, they are hydrofluoric acid and hot
phosphoric acid.

 Advantages:
•More reliable than the non technical tests.
•Used for both man made fibers and natural fibers.
•Easily conducted.
Limitations
•Certain manufacturing and finishing processes like
mercerizing, affects the appearance of the fibers under the
microscope.
•Very dark colored fabrics cannot be identified under
microscope.
•Dye stuffs must be removed from fabrics.

Identification of textile fibers.

Identification of textile fibers.

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Identification of textile fibers.