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Mechanical, Fiber Properties,

Structure

By hammad mohsin

Spr2012

D. Material Properties

1. Elastic

a. Elastic Behavior causes a

material to return to its

original shape after being

deformed.

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b. Completely elastic

behavior

Force

(F)

kxF =k is called the elastic

modulus

Distance (x)

2. Viscous

a. Viscous behavior is related to the rateo e orma on.

t

xF

Viscosity Rate of deformation

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force, F

as

slow

distance, x

3. Viscoelastica. Fibers exhibit viscoelastic behavior

b. force required to deform a materialdependents amount of deformation and

rate at which the material is deformed

fast

x

elastic

slow

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III. Fiber Science.

1. High length to width ratio

2. Breaking strength

3. Spinning quality

.

B. Secondary Properties

1. cross-sectional shape

.

3. luster

4. color

5. moisture absorption

.7. flammability

8. chemical resistance

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IV. General Fiber Characteristics

.1. Length

(short staple 0.5 2.5 inches, long staple > 2 inches)

2. Diameter- ,

microns)

3. Cross-sectional shape4. Crimp

5. Color

B. Internal Structure1. Chemical Composition

2. Crystallinity

Polymer chains or sections packed together

3. Orientation

Alignment of chains along fiber axis

. 1. Melting Temperature

2. Glass Transition Temperature

Most polymers are thermoplastic theysoften before melting

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D. Physical Properties1. Breaking Strength

2. Breaking ElongationAmount of stretch before breaking

3. ModulusResistance to deformation

4. ToughnessAmount of energy absorbed

5. ElasticityAbility to recover after being deformed

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E. Chemical Properties1. Density

. .

2. Moisture Regain

(0 to 20 %)

3. Chemical Resistance

4. Dyeability

Fiber structure & Properties

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Fiber Structure investigation

Fiber cross section

Fiber cross section are mainly divided

A) Round

B) Profiled

Profiled encompasses 2-lobed, 3-lobed(trilobal), rectangular (rounded, 4-lobed)and star-shaped (n-lobed)

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Uniformity of yarns and fibers

Non-uniformity (= fluctuation of characteristic,

external nature

External uniformity is often judged visually(sometimes using auxiliary agents) or can berecognized in textile fabrics.

the properties of the fiber structure, and is notusually directly visually recognizable.

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External Uniformity

Uster CV

calculated

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Non-uniformity causes (some)

- Polymer condition

Viscosity (molecular weight and temperatureuniformity)

- Spinning machine

Extruder faults, e.g., loss of pressuremelttemperature and deviationsspinnerettemperatureinsulation or bedding in of thespinneretsquench chamber faults and flow

pat ternquench ai r f low rate, quench ai r veloci ty,

winder eccentricity- and bearing problems, roll

contamination and damagetraverse mechanismand its faultsspin finish faults (defective or false,too high or i rregular)variation in interminglingintensity and poor filament cohesiontake-up speederrors

- Drawtwist machines.

Godet eccentricity, bearing problems, roll contamination anddamagedefective separator rollsdifferences in drawing, drawingfaults, yarn slipping over the rollsdefective yarn guides or ringtravelerseccentric and vibrating spindlesyarn tension variations.

cop)- Warp-draw machines

deviations in the draw ratiodefective reedsproblematicn erm ng ngs ar an s op nes a er a yarn rea warp yarn enchange resulting from a yarn break.

- Twisting machines

changes in the number of twis ts yarn tension variations due to twistgenerationwinding prob lems.

- Texturizing machines

bad package formationdrawing problems during drawtexturizingheater temperature uniformity (venting, cok ing)too high a yarn speed

twist sl ippage at the twist aggregaterotational speed of the tw istaggregates and their uniformitydisk surfacesdeposits

- Polymer condition/state viscosi ty, factors affecting viscos ity and its uniformitydifferences in

chip moisture

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Fiber Fineness determination