SUBMITTED TO: SIR IMRAN RAZA

SUBMITTED BY: RABIA MEHMOOD

CLASS: AMM-01

DATE: 28TH APRIL 2016

Identification of textile 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.

TYPES OF TEST Chemical Analysis Microscopic analysis Floatation Test Twist on Drying Burning test

Cotton fiber BURNT TEST Ignites and burns quickly, may flare, leaves a glowing ember after

flame is extinguished. Smoke is white or light colored and smells like burnt paper or leaves. Ash is light gray or white and very soft.

MICROSCOPIC TEST: 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. Under a microscope, it looks like flat, spirally twisted ribbon Like tube with rough granular surface. However mercerized cotton doesn't have natural twist. The finishing process makes them swollen, straight, smooth and round with a shining surface.

CHEMICAL TEST:Cotton is immersed in a 1% solution of fuchsine in alcohol to give red

rose color. Later ,it is washed and immersed into ammonia, cotton does not retains any coloration.

FLAX FIBER CHEMICAL TEST: Linen is 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.

BURNT TEST: 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.

MICROSCOPIC TEST: Under the microscope, the hair like flax fiber shows several sided

cylindrical filaments with fine pointed ends. The fiber somewhat resembles a straight, smooth.

SILK FIBER BURNT TEST: Burns, but does not melt. It shrinks from the flame. It has the odor

of charred meat. The residue is a black, hollow irregular bead that can be easily to a gritty black powder. It is self-extinguishing, i.e., it burns itself out.

CHEMICAL TEST: The use of concentrated cold hydrochloric acid will dissolve the

silk and the wool fiber swells.

MICROSCOPIC TEST: 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. Wild silk or tussah fiber has different appearance than the cultivated silk. It is flattened, coarse, thick and broader fiber having fine, wavy lines all across its surface whereas cultivated silk is narrower fiber with no marks on it.

RAYON FIBER BURNT TEST: Is a manufactured cellulose fiber. It burns without flame or

melting and may flare up. Unless there is a fabric finish, it doesn't leave any bead. After the flame is removed, it may glow a bit longer than cotton. It smells like burning paper and leaves soft, gray ash. It's smoke is a little hazardous.

CHEMICAL TEST:All rayon's will dissolve in a 60% solution of sulfuric acid or a concentrated solution of hydrochloric acid.

MICROSCOPIC TESTRayon fiber has uniform diameter with glass like shine. If delustered

then rayon fiber shows marks similar to pepper, when viewed cross sectionally. Viscose fiber of rayon looks irregular when viewed cross sectionally.

POLYESTER FIBER BURNT TEST: Is a polymer produced from coal, air, water, and petroleum

products. It burns quickly and shrinks away from flame, may also flare up. It leaves hard, dark, and round beads. After the flame, it burns slowly and is not always self-extinguishing. It has a slightly sweet chemical odor. It leaves no ash but its black smoke and fume are hazardous.

CHEMICAL TEST: 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.

MICROSCOPIC TEST: Generally, polyester fiber is smooth, straight. It looks round cross

sectionally. However, with various finishing processes, its appearance changes in context of texture and luster. This general characteristics may be altered to achieve certain characteristics.

WOOL FIBER BURNT TEST: Is a protein fiber which burns slowly. It sizzles and curls away from

flame and may curl back onto fingernail. It leaves beads that are brittle, dark, and easily crushed. It is self-extinguishing and leaves harsh ash from crushed bead. It gives out a strong odor of burning hair or feathers. It gives out dark smoke and moderate fume.

CHEMICAL TEST: As strong alkali destroy animal substances, a 5%of soda lye

solution in water can be used to eliminate wool fibers from a sample that contains a mixture of fiber. The vegetable fibers will not be affected by this solution.

MICROSCOPIC TEST: Wool fiber has irregular, roughly cylindrical, multi cellular

structure with tapered ends. Under a microscope, three basic layers are shown- epidermis (outer layer), cortex (middle layer) and medulla (inner layer). Medulla is seen only in coarse and medium wool fibers and that too under a highly powerful microscope. 

NYLON FIBER BURNT TEST: Are made from petroleum. Due to their fabric finish, they quickly

burn and shrink to flame. The beads are hard, grayish and uncrushable. After flame, they burn slowly and melt. They are self-extinguishing but drip dangerously. Their odor is like celery and they leave no ash but the fume is very hazardous.

CHEMICAL TEST: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. A fiber stained with dilute acetic acid turns to a specific color. The same fiber when stained with mild alkali like soda carbonate turns to a different color again specific to that

fiber only. Nylon turns beige in one and bright red in other.

MICROSCOPIC TEST: There are many variants of nylon fiber. However, generally it appears fine, round, smooth and translucent. Sometimes it has shiny appearance. If it looks dull, it will also be dotted under the microscope. It is also produced in multilobal cross-sectional types.

ACRYLIC FIBER BURNT TEST: 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.

CHEMICAL TEST:Acrylic fibers will dissolve in 70 percent solution of ammonium

thiocyanate at 130 degree Celsius but the other fibers will not.

MICROSCOPIC TEST: It has an almost round cross section. ORLON ACRYLIC: It has a

flat, nut-shaped cross section. ACRILAN ACRYLIC: It has a bean-shaped cross section, its longitudinal appearance is straight and smooth.