Identification of textile fibers

MD.AZMERI LATIF BEG
MSC. IN TE
IDENTIFICATION OF
TEXTILE FIBERS

Textile Fiber; Fiber is a near microscopic hair-like substance that
may be natural or manmade. Fibers suitable for textile use possess
adequate length, fineness, strength, and flexibility for yarn
formation and fabric construction, and for withstanding the
intended use of the completed fabric. Other properties affecting
textile fiber performance include elasticity, crimp (waviness),
moisture absorption, reaction to heat and sunlight, reaction to the
various chemicals applied during processing and in the dry
cleaning or laundering of the completed fabric, and resistance to
insects and micro-organisms.

INTRODUCTION
 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.

BURNING TEST
Cotton Fiber Linen Fiber

BURNING TEST
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.

BURNING TEST
Silk Fiber Wool Fiber

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

BURNING TEST
Acrylic FiberAcetate Fiber

BURNING TEST
 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.

BURNING TEST
Polyester FiberNylon Fiber

BURNING TEST
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

M I C RO S C O P I C T E S T F O R N AT U R A L F I B E R S
 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.

MICROSCOPIC TEST
Cotton Fiber Linen fiber

MICROSCOPIC TEST
 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 TEST
Silk fiberWool fiber

M I C RO S C O P I C T E S T F O R M A N M A D E F I B E R S
 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.

MICROSCOPIC TEST
Acetate fiber Rayon fiber

MICROSCOPIC TEST
 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.

MICROSCOPIC TEST
Polyester fiberNylon fiber

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.

CHEMICAL TEST
 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.

CHEMICAL TEST
 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

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