Properties of Fibers

1. Fiber Science
By Chamal Jayasinghe [B.Sc. Engineering (Textiles)]

2. FibersFibers
A thin long flexible structure InA thin long flexible structure In
witch, the ratio of length to diameterwitch, the ratio of length to diameter
is very high.is very high.
This ratio should be at least 100: 1 toThis ratio should be at least 100: 1 to
be considered as a fiber.be considered as a fiber.
To spin textile yarn successfully thisTo spin textile yarn successfully this
ratio should be at least 1000: 1ratio should be at least 1000: 1

3. Examples for length to diameter ratio
Fiber Type Length Diameter Length:Diameter
Cotton 1” 0.0007” 1,400:1
Wool 3” 0.001” 3,000:1
Flax 1” 0.0008” 1,200:1

4. Other Needful Qualities of
Fibers
Thinness
Flexibility
Sufficient Strength
Sufficient Length

5. Fiber Classification

6. Staple and Filament Fibers
Fibers with infinite length(long) are
called filament fibers
Fibers with finite length length(relatively
short length ) is called staple fibers.

7. Monomers → Polymers → Micro fibrils
→ Fibrils → Plant Cell Walls → Fibers
Monomers are single structure
composed of atoms.
Internal Structure of a Natural
Fiber

8. From Monomer to FiberFrom Monomer to Fiber

9. From Monomer to FiberFrom Monomer to Fiber

10. Looking in to PolymerLooking in to Polymer
ArrangementsArrangements

11. Crystalline & Amorphous Regions

12. Crystalline & Amorphous Regions
Crystalline – Orderly arrangement of molecular chains
Less internal spaces
Higher strength due to better orientation
Poor water penetration properties
Gives strength to the fiber
Amorphous – Random arrangement of molecular
More internal spaces
Good water absorption
Lower strength due to poor orientation of
molecules.
Gives flexibility to fiber

13.  The degree of polymerization, or DP, is usually defined asThe degree of polymerization, or DP, is usually defined as
the number of monomer units in a macromolecule orthe number of monomer units in a macromolecule or
polymer molecule.polymer molecule.
Degree of PolymerizingDegree of Polymerizing

14. Degree of Polymerization withDegree of Polymerization with
Melting TemperatureMelting Temperature

15.  Nylon 6 -120Nylon 6 -120
 Nylon 6,6-200Nylon 6,6-200
 Polyester (PET)- 100Polyester (PET)- 100
 Polyacrylonitrile > 2000Polyacrylonitrile > 2000
 Viscose Rayon- 150-350Viscose Rayon- 150-350
 Polynosic- 700-1100Polynosic- 700-1100
 Cotton- 4000-10,000Cotton- 4000-10,000
 Wool- 60,000-100,000Wool- 60,000-100,000
DP of Common FibersDP of Common Fibers

16.  Chemical constituent of polymer(monomer)
is mainly responsible for the chemical
properties of textile fibers.
 Physical arrangement of polymer chains in
fiber structure and polymer chain length is
mainly responsible for physical properties of
textile fibers.
Chemical and Physical
Properties of Fibers

17. PhysicalPhysical
Properties ofProperties of
FibersFibers

18. The strength of textile fibers is
referred to as their tenacity. It is
determined by measuring the force
required to rupture or break the fiber.
Sufficient tenacity is required to
withstand the mechanical and
chemical processing as well as make
textile products which are durable.
Tenacity

19. General Fibre Properties
1.Tenacity
Molecules parallel to the longitudinal axis take their
fair share of the load result in high tenacity (breaking
load).
Molecules lying approximately at right angles to the
longitudinal axis take little or none of the load hence
result in low breaking load.

20. Effects of Polymer Length to TenacityEffects of Polymer Length to Tenacity

21. Area of attraction that is greater in the long molecules
than in short molecules.
Therefore fibers consist of longer molecules are stronger
than fibers consist of shorter molecules.
Up to a certain point fiber strength will increase along
with increasing molecular chain length.
Effects of Polymer Length
to Tenacity

22. FinenessFineness

23. 2.Fineness
Fibre fineness governs the end use application of fibre.
Fibres used in clothing fabrics are below 5 decitex and
rarely exceeds 15 decitex. .
As the average number of fibres in the cross section is
high, fine, staple fibres are more suitable for production
regular yarns.
Cloths made from fine fibres or filaments have a softer
smother handle
Has lower resistance to abrasion in fabrics as fine fine
fibres can be easily damaged.
Also being more flexible, they are liable to entangle
with foreign matter and form pillings.
General Fibre Properties

24. Moisture AbsorptionMoisture Absorption

25. The ability of a fiber to absorb moisture is referred in moisture
regain or moisture content.
The quantity of moisture picked up varies with the relative humidity
and the temperature of the atmosphere-The standard values are relative
humidity of 65% and temperature of 20C.
Depends on the chemical nature and physical arrangement of fiber.
Moisture Absorption

26. Moisture ContentMoisture Content
Moisture Content % =Moisture Content % = MoistureMoisture x 100 %x 100 %
Total MassTotal Mass

27. Moisture RegainMoisture Regain
Moisture Regain % =Moisture Regain % = MoistureMoisture x 100x 100
%%
Dry MassDry Mass

28. The influence of moisture
absorption of fibers.
The comfort of the wearer.
The amount of shrinkage that will
occur during laundering.
The speed with which the textile
will dry after laundering.
How does the fabric or fiber
neutralize static electricity
Moisture Absorption

29. Abrasion ResistanceAbrasion Resistance

30.  Fabrics are abraded in use against various materials
 The life of a fabric is dependent on its resistance to
abrasion.
 Nylon has an outstanding resistance to abrasion.
 Abrasion resistance is decided by it’s fiber
composition yarn and fabric construction.
Abrasion Resistance

31. Crease RecoveryCrease Recovery

32.  To retain a good appearance of a fabric , they must have good
crease recovery from unwanted creases occur in fabric usage
and laundering.
 When a fiber is bent, two things can happen
1.The cross links may break and join in new positions.
When
the load is removed, recovery from the crease is restricted
by the new positioning of the cross links and textile will
show poor crease recovery.
2.The cross links may be stretched without breaking.
When the load is removed, they will tend to return the fiber
to its original shape and will show good crease recovery.
Crease Recovery

33. Elongation & Elastic RecoveryElongation & Elastic Recovery

34. The amount of extension or stretch that a fiber accepts is
referred to as elongation.
Elastic recovery indicates the ability of fibers to return to
their original length after being stretched.
.
Elongation and elastic
recovery

35. ResiliencyResiliency

36. ResiliencyResiliency
Resiliency refers to the ability of a fiber to come back to its originalResiliency refers to the ability of a fiber to come back to its original
position after being creased , folded or any type of physical stress.position after being creased , folded or any type of physical stress.
Good elastic recovery usually indicates good resiliencyGood elastic recovery usually indicates good resiliency
Excellent resiliency is exhibited by polyester, wool and nylon fibers.Excellent resiliency is exhibited by polyester, wool and nylon fibers.
Flax, rayon and cotton, on the other hand, have a low resiliencyFlax, rayon and cotton, on the other hand, have a low resiliency

37. LusterLuster

38. Luster is amount of light reflected from the surface of the fibre
Fine fibers provide a greater number of reflecting surfaces. Hence
good luster
Fibers with a uniform diameter has a greater luster.
The shape of the cross section affects the degree of luster.
yarns made from continuous filaments are more lustrous than those
made from short fibers.
 Manufactured fibers can have their luster subdued by adding
delustering agents.
Luster

39. FlexibilityFlexibility

40.  Fibers should be flexible in order to be made into yarns
and thereafter into fabrics that permit freedom of
movement. Certain end uses require greater flexibility,
e.g., automobile seat belts.
Flexibility

41. UniformityUniformity

42.  Uniformity of fibers towards itsUniformity of fibers towards its
length, ensure production of evenlength, ensure production of even
yarns which can then form fabrics ofyarns which can then form fabrics of
uniform appearance and consistentuniform appearance and consistent
performance.performance.
UniformityUniformity

43. StiffnessStiffness

44. Stiffness is a special property of fabric. It is the
tendency of fabric to keep standing without any
support. It is a key factor in the study of handle and
drape of fabric.
Stiffness of the fibers and fabric structure greatly affect to this
quality of the fabric.
Stiffness

45. Chemical Properties

46. Reaction with AcidsReaction with Acids
Most of the cellulose based fibers dissolves in acids.Most of the cellulose based fibers dissolves in acids.
While Protein Fibers has a quite good resistance to Acids.While Protein Fibers has a quite good resistance to Acids.
Synthetic fibers has less or no reaction with acids at lowSynthetic fibers has less or no reaction with acids at low
temperatures and low concentrations. But reacts at hightemperatures and low concentrations. But reacts at high
temperatures and concentrations.temperatures and concentrations.

47. Most of the Protein Based fibers react with alkali.Most of the Protein Based fibers react with alkali.
While Cellulosic fibers has a good resistance to alkali.While Cellulosic fibers has a good resistance to alkali.
Synthetic fibers has less or no reaction with acids at lowSynthetic fibers has less or no reaction with acids at low
temperatures and low concentrations. But reacts at hightemperatures and low concentrations. But reacts at high
temperatures and concentrations.temperatures and concentrations.
Reaction with AlkaliReaction with Alkali

48. It is valuable for a fiber to withstand when exposed toIt is valuable for a fiber to withstand when exposed to
organic solvents. Because these solvents has a highorganic solvents. Because these solvents has a high
tendency to contact with fabrics in day to day usage.tendency to contact with fabrics in day to day usage.
Organic SolventsOrganic Solvents
1. Ethyl alcohol1. Ethyl alcohol
2. Methyl alcohol2. Methyl alcohol
3. Paint thinner3. Paint thinner
Reaction to Organic SolventsReaction to Organic Solvents

49. Bleaching is used everywhere in the textile industry.Bleaching is used everywhere in the textile industry.
A fiber must be resistance to bleaching at least to a certainA fiber must be resistance to bleaching at least to a certain
stage to become a good textile fiber.stage to become a good textile fiber.
Bleaching is done in fiber stage, Fabric stage and garmentBleaching is done in fiber stage, Fabric stage and garment
stage as well.stage as well.
Effects of BleachingEffects of Bleaching

50. Resistance to MildewResistance to Mildew

51. Resistance to InsectsResistance to Insects
Insects stays in fabrics
Where they have enough
Warmth, food and
Protection as well.
Some fibers have good
Insect repellent qualities
From its nature
Ex. linen

52. Since people are interested and interacted withSince people are interested and interacted with
colors, it is important for textile fibers as wellcolors, it is important for textile fibers as well
Ability to DyeAbility to Dye