1. Fiber properties
Lili
M.Sc (C.T.) 3rd sem.

2. Definition-
 Fiber properties are essential thing to know for
various end uses and the products made from it
qualify on the basis of certain parameters.
 The various properties are-
 High fiber length to width ratio.
 Tenacity (adequate strength).
 Flexibility or pliability.
 Cohesiveness or spinning pliability
 Uniformity.

3.  Fiber morphology
 Specific gravity
 Elongation and elastic recovery
 Resiliency
 Moisture regain
 Flammability and other thermal reactions
 Electrical conductivity
 Abrasion resistance
 Chemical reactivity and resistance
 Sensitivity to environmental conditions.

4.  High length to width ratio-
 A pre-requisite for processing of fibers into yarns
and fabrics is that their lengths must be more than
widths. The minimum length to breadth ratio is
100:1.
 Length of fibers is also a basis for classifying them
into two groups staple and filament. Staple fibers
are of relatively short length fibers; and filament
fibers are long length fibers.
 The fineness of a natural fiber is a major factor in
ascertaining quality and is measured in microns(1
microns= 1/1000millimeter). In general, finer fibers
are softer, more pliable and have better drapability.
They are, thus, considered superior and form
better yarns and fabrics. Fineness of man-made

5.  Tenacity-
 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 is, directly related to the length of the
polymers, degree of polymerization, strength in
dry and wet conditions, and types of inter-
polymer forces of attraction formed between the
polymers.

6.  Flexibility-
 Fibers should be flexible or pliable 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.
 Uniformity-
 Uniformity of fibers towards its length, ensure
production of even yarns which can then form
fabrics of uniform appearance and consistent
performance.

7.  Cohesiveness or spinning quality-
 It is the ability of the fiber to stick together
properly during yarn manufacturing processes.
 Natural fibers have inherent irregularities in
their longitudinal or cross sections which permit
them to adhere to each other during fiber
arranging.
 In case of synthetics, filament lengths aid in
yarn formation. Texturing introduces coils,
crimps, curls or loops in the structure of an
otherwise smooth filament. It is used to impart

8.  Morphology-
 It is the study of physical shape and form of a
fiber. It includes microscopic structure like
longitudinal and cross sections. These also
include fiber length, fineness, crimp, color and
luster.
 Physical shape-
 shape of a fiber include, its longitudinal
sections, cross section, surface contour,
irregularities and average length.

9.  Luster-
 It refers to the sheen or gloss that a fiber
possesses. It is directly proportional to the
amount of light reflected by a fiber.
 This in turn is affected by their cross section
shape.
 Among the natural fibers, silk or the queen of
Cross sectional shape Degree of luster
Round High
Irregular Low
Kidney shaped Low
Oval High
Trilobal High
octagonal Low

10.  Deluster-
 A delusterant is a substance that is added to
the dope before spinning of manufactured
fibers.
 Finally powdered metallic salts like titanium
dioxide (TiO2) and geranium dioxide (GeO2) are
used. These act as discontinuities in an
otherwise regular, uniform reflection of light.
 The amount of delusterant added could vary
and thus result in semi-lustered or delustered
fibers.

11.  Specific gravity-
 The specific gravity of a fiber is the density
related to that of water(at 4°c).
 The density of water at that temperature is 1.
fiber density will affect their performance and
laundering.
 If the specific gravity of a fiber is less than 1, it
will float in water, making its washing and
dyeing very difficult. E.g. Olefins fiber.
 A related property is density which is defined as
the mass per unit volume and measured in

12.  Elongation and elastic recovery-
 The amount of extension or stretch that a fiber
accepts is referred to as elongation. Elongation
at break is the amount of stretch a fiber can
take before it breaks.
 Elastic recovery indicates the ability of fibers to
return to their original length after being
stretched. A fiber with 100% elastic recovery
will come back to its original length after being
stretched to a specific degree for specified
period of time. After removing and re-
measured.

13.  Resiliency
 Resiliency refers to the ability of a fiber to come
back to its original position after being creased
or folded. Resilient fibers recover quickly from
wrinkling or creasing. Good elastic recovery
usually indicates good resiliency. This property
is described qualitatively and ranges from
excellent to poor. Excellent resiliency is
exhibited by polyester, wool and nylon fibers.
Flax, rayon and cotton, on the other hand, have
a low resiliency.

14.  Moisture regain-
 The ability of a bone dry fiber to absorb
moisture is called moisture regain.
Measurements are done under standard testing
conditions (70°± 2F and 65% ±2% relative
humidity). Saturation regain is the moisture
regain of a material at 95-100% relative
humidity. Both regain and content are
expressed as a percentage.
 Moisture regain= wt. of water in a material × 100
oven dry wt.
 Moisture content= wt. of water in a material × 100
total wt.

15.  Flammability and other thermal reactions-
 Burning characteristics of fiber groups vary
from each other and can, thus be used as an
authentic identification method. Reaction to
flame can be further broken down into; behavior
when approaching flame, when in flame, after
being removed from flame.
 Thermal characteristics of fibers are important
in their use and care like washing, drying and
ironing are selected on the basis of a fiber’s
ability to withstand heat.

16.  Electrical conductivity-
 It is the ability of a fiber to transfer or carry
electrical charges. Poor or low conductivity
results in building up of static charges. This
leads to the clinging of clothing and in extreme
cases can produce electrical shocks, which
produce crackling sound or even a tiny spark.
Acrylic is a poor conductor of electricity.
 water is an excellent conductor of electricity
and fibers with high moisture regains will never
face the problem of static build-up.

17.  Abrasion -
 The wearing away of a material by rubbing
against another surface is called abrasion.
Different kinds of abrasion are identified, these
are-
 Flex abrasion- when a fabric bends/folds and
rubs against another surface e.g. on elbow or
knee areas.
 Flat or plane abrasion: when a flat surface rubs
against another surface e.g. on thigh area of a
pair of jeans.

18.  Chemical reactivity and resistance-
 Chemical reactivity plays a key role in
manufacture, application of finishes and care of
fabrics.
 Resistance to acids, alkalis and organic
solvents in similar for fibers of one chemical
composition. Thus, cellulosic's are fairly
resistant to alkalis but get harmed by acids and
the reverse is true for protein fiber.

19. Thank
you