mechanical, fiber properties, structure
TRANSCRIPT
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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