fiber+identification

8/7/2019 Fiber+Identification

1/7

Identification of textile fibers

Fiber identification is done by three main tests which areas follows:

1. Burning Test

2. Microscopic Evaluation

3. Chemical test


2/7

Burning Test for Cellulosic fibers

FiberFiber ApproachiApproachi

ng Flameng Flame

In theIn the

flameflame

AwayAway

fromfromFlameFlame

OdorOdor ResidueResidue

CottonCotton Does not Does notshrinkshrinkaway,away,

ignites onignites oncontactcontact

BurnsBurnsquicklyquickly

ContinuesContinuesburningburningwith anwith an

after glowafter glow

Smell ofSmell ofburningburningpaperpaper

Light,Light,fluffy, greyfluffy, greyin color,in color,

easy toeasy tocrushcrush

RayonRayon Does not Does notshrink awayshrink away

BurnsBurnsquicklyquickly

ContinuesContinuesburningburningwith anwith an

after glowafter glow

Smell ofSmell ofburningburningpaperpaper

LightLightfeatheryfeatheryresidue inresidue in

very smallvery smallamountamount


3/7

Burning Test for Protein Fibers

FiberFiber ApproachingApproachingFlameFlame

In theIn theflameflame

Away fromAway fromFlameFlame


SilkSilk Curls awayCurls away

from thefrom theflameflame

BurnsBurns

slowly andslowly andsplutterssplutters

SelfSelf

extinguishextinguish--inging

Smell ofSmell of

burningburninghairhair

Black beadBlack bead

likelikeresidue;residue;crisp &crisp &crushablecrushable

WoolWool Curls awayCurls awayfrom thefrom the

flameflame

BurnsBurnsslowlyslowly

SelfSelfextinguishextinguish--

inging

Smell ofSmell ofburningburning

hairhair

BrittleBrittlesmall beadsmall bead

likelikeresidue,residue,crisp andcrisp andcrushablecrushable


4/7

Burning test for Synthetic fibers

FiberFiber ApproachinApproaching Flameg Flame

In theIn theflameflame

Away fromAway fromFlameFlame


PolyesterPolyester Fuses,Fuses,melts andmelts andshrinksshrinksaway fromaway fromflameflame

BurnsBurnsslowly andslowly andmeltsmelts

SelfSelfextinguishinextinguishingg

Smell ofSmell ofchemicalschemicals

Hard,Hard,toughtoughblack/browblack/brown beadn bead

AcrylicAcrylicFuses,Fuses,melts andmelts and

shrinksshrinksaway fromaway fromflameflame

BurnsBurnsrapidly andrapidly andsputterssputters

Continues toContinues toburn & melt.burn & melt.Hot moltenHot moltendrops falldrops fallwhilewhileburningburning

AcidicAcidicodorodor Hard blackHard blackregularregularbead,bead,crushablecrushable

NylonNylon Fuses,Fuses,melts andmelts andshrinksshrinksaway fromaway fromflameflame

BurnsBurnsslowly andslowly andmeltsmelts

SelfSelfextinguishinextinguishingg

SyntheticSyntheticodorodor

Hard,Hard,toughtoughblack/browblack/brown beadn bead


5/7

Chemical test for Cellulosic fibers

S.NoS.No

..

ExperimentExperiment ObservationObservation InferenceInference

1.1. Take the fiber and dip it inTake the fiber and dip it in3030--50% Sulphuric acid and50% Sulphuric acid andheatheat

The fiber charsThe fiber charsand dissolves.and dissolves.

Cellulosic fiber,Cellulosic fiber,could be cottoncould be cottonor rayonor rayon

2.2. Take the fiber and dip it inTake the fiber and dip it in60% sulphuric acid solution in60% sulphuric acid solution ina test tube and leave it for 5a test tube and leave it for 5--10 minutes at room10 minutes at roomtemperaturetemperature

Fiber dissolvesFiber dissolves

Fiber does notFiber does notdissolve (maydissolve (maydisintegrate)disintegrate)

Rayon confirmedRayon confirmed

Cotton confirmedCotton confirmed


6/7

Chemical test for Protein fibers

S.NoS.No..


1.1. Boil the fiber in 5% solutionBoil the fiber in 5% solutionof Sodium hydroxideof Sodium hydroxide

Fiber dissolvesFiber dissolves Could be silk orCould be silk orwoolwool

2.2. Cool the above solution andCool the above solution andadd lead acetateadd lead acetate

White/No ppt.White/No ppt.

Black ppt.Black ppt.

Silk ConfirmedSilk Confirmed

Wool confirmedWool confirmed


7/7

Chemical test for Synthetic fibers

Maintain the sequence as both nylon and acrylic also get

dissolved in meta-cresol but polyester gets dissolved only inmeta-cresol.

S.NoS.No

..


1.1. Add the fiber in 85% solutionAdd the fiber in 85% solutionofFormic acid at roomofFormic acid at roomtemperaturetemperature

Fiber dissolvesFiber dissolves Nylon confirmedNylon confirmed

2.2. Add the fiber in DMF (dimethylAdd the fiber in DMF (dimethylformaldehyde) solution. Heatformaldehyde) solution. Heatslightlyslightly

Fiber dissolvesFiber dissolves Acrylic confirmedAcrylic confirmed

3.3. Add the fiber to metaAdd the fiber to meta--cresolcresol

solution. Heatsolution. Heat

Fiber dissolves onFiber dissolves on

strong heatingstrong heating

PolyesterPolyester

confirmedconfirmed

fiber+identification

Documents