Technical Test of Fiber

Identification of different fibers by

microscopically & chemical test

SL NO 01 Faysal IslamFaysal IslamFaysal IslamFaysal Islam02 Shahriar AlShahriar AlShahriar AlShahriar Al03 Mohammad SajibMohammad SajibMohammad SajibMohammad Sajib04 Sumon MiahSumon MiahSumon MiahSumon Miah

Textile Testing & Quality Control

Topic:


microscopically & chemical test

Submitted to:

Umera Islam

Lecturer of B.S.T.E.

City University

Submitted by

NAME Faysal IslamFaysal IslamFaysal IslamFaysal Islam 09090909

Shahriar AlShahriar AlShahriar AlShahriar Al----SehabSehabSehabSehab 09322131093221310932213109322131Mohammad SajibMohammad SajibMohammad SajibMohammad Sajib 09322079093220790932207909322079

Sumon MiahSumon MiahSumon MiahSumon Miah 09322121093221210932212109322121

Date: 25/01/2011

1

Textile Testing & Quality Control-1


microscopically & chemical test.

ID 09090909322015322015322015322015 09322131093221310932213109322131 09322079093220790932207909322079 09322121093221210932212109322121

Date: 25/01/2011

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Our topic is Microscopic test & chemical test of various fibers. But before this we should know the

classification of test, because “A LITTLE LEARNING IS A DENGEROUS THING”.

Full information of anything can increase quality of a work. For this we are trying to focus on Technical

test broadly Which is consist of microscopic test chemical test. It’s impossible to recognize with certainty

every fiber by chemical means alone .the microscope alone will do this, but a combination of chemical

and microscopical methods usually removes all doubt .An additionally advantage of microscopical

testing is the fact that very small samples may be used and that the samples are not destroyed .

Those two types of testing discussed under Technical test.

Few words on Technical Test

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.

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Technical’s tests require high skilled person know how to handle 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.

Requirements for tests:

� Preparation of test specimen.

� Apparatus for microscopic examination.

� Reagents used for chemical tests.

� Other tools and equipment.

WHAT IS 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 powers.

� The test can easily distinguish between fibers.

� The test identifies the natural fibers more easily as compared to manmade ones.

� Synthetic fibers are very similar in appearance and the increase in the number of varieties, make

s it a little tough to distinguish the fibers even under a microscope.

Microscopic test for different fibers:

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 200 to

400 convolutions per

inch.

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LINEN:

Wool

Under the microscope, the hair like flax fiber shows several sided cylindrical filaments with fine pointed ends. The fiber somewhat resembles a straight smooth line.

Under the microscope , wool’s cross section shows three layers- epidermis, cortex and the medulla.

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Silk

Rayon

Acetate

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.

Rayon fibers have a glasslike

luster under the microscope

and appear to have a uniform

diameter when viewed

longitudinally.

The cross sectional view has a bulbous or multifocal appearance with indentations. These indentations appear as occasional markings or

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Nylon

Polyesters

Spandex

Generally, polyester fibers are

smooth and straight and the

cross-section is round.

This general characteristics

may be altered to achieve

The basic microscopic appearance

is generally fine ,

round, smooth, and

translucent. it is also produced in

multifocal cross-sectional

types.

z

Spandex fibers are unique in

appearance, they appear to be

groups of fibers fused together.

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Glass

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 undertaken 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

The fiber is smooth, round,

translucent, highly lustrous,

and quite flexible.

CHEMICAL TEST

Stain Test

Solvent test

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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.

Some tests

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 fibers:

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.

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Distinguishing Polymer from other fibers:

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 from other fibers:

Acrylic fibers will dissolve in 70 percent solution of ammonium thio cyanate 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 other fibers:

There are two specific solvents for quick identification of glass fibers, they are hydrofluoric acid

and hot phosphoric acid.

This technical fibre identification test has the following advantages

and limitations:

Advantages:

� More reliable than the non technical tests.

� Used for both manmade 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.

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Fiber

test

Soda

ash

40%

soln

Caustic

soda

25%

soln

Sodium

hypoch

oloride

Hydro

c

Holori

c

acid

40%

Nitric

asid

15%

Nitric

asid

70%

Sulphur

ic acid

15%

Sulphur

ic acid

70%

Burning in

flame

Microsc

Opic view

remarks

viscos swells Swells

&

shines

Gets

weeken

d

Turns

Yello

w

Dissolv

es

On

heating

Dissolve

s

Dissolves

Dissolv

es

quickly

Burns

contin

uously

leaving

gray ash of

burning

paper

smell

Longit

udinal

Irregu

lar lines

Soft

filament

Good

lusture

Silk Loss

strengt

h

Dissolv

es

Dissolv

es

Slowly

-------

-------

Dissolve

s

Partially

--------

Dissolv

es

self

extinguishi

ng

leaves

crushable

black beads

Densed

centre

Line

uneven

Coating

delicate

luster

filament

Wool Do Do Dissolv

es

------- ------- Dissolve

s

Slowly

------- ------- self

extinguishi

ng

leaves

crushable

black beads

fish

Scales

Structure

Rough

crimpy

fibre

polyest

er

------- ------- ------- ------- ------- Dissolve

s

Slowly

Prolonge

d

treatme

nt

Transpare

nt hard

beads

Dissolv

es

Slowly

Burns

&stop

leveling

semi

Transluce

nt

uniform

Resistant

of

chemical

Acrylic ------- ------- ------- ------- ------- Loss

Strength

&

Dissolve

s

Slowly

------- Turns

yellow

brown

Dissolves

&turn

yellowish

brown

Burn stop

of flame

leveling

dark

beads

Transluce

nt

uniform

lofty &

more

volumino

us

Nylon ------- ------- ------- ------- ------- Loss

Strength

------- Dissolv

es

Slowly

Burn stop

of flame

leveling

dark beads

Transluce

nt

uniform

Strong

more

elastic

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Technical Test of Fiber