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1. ARBA MINCH UNIVERSITY
COLLEGE OF NATURAL SCIENCES
DEPARTMENT OF CHEMISTRY
COURSE: TEXTILECHEMICAL PROCESSING SCIENCE AND TECHNOLOGY.
PRESENTATION ON MERCERIZATION
BY/ FRANCO JOHN
DATE: 4TH .JAN. 2017

2. Objectives of mercerization:
To improved lustre (shiny).
To increased ability to absorb dye and moisture
regain.
To improved reactions with a variety of
chemicals.
To improved strength/elongation.
To improved smoothness and hand feel.
To improved stability of yarn form.

3. Introduction to mercerization:
Mercerization was found by John Mercer in 1844 of
England, who treated cotton fibers with NaOH.
.(sometimes NH3, LiOH or KOH being used)
The process did not become popular until
Horace. A. Lowe improved it into its modern
form in 1890.
By holding the cotton during treatment to
prevent it from shrinking, Horace Lowe found
that the fibre gained a lustrous appearance.
In the process of mercerization four factors are
considered: NaOH conc., time, temperature and
tension.

4. This mercerization is applicable only on cellulosic fibres
The main purpose of mercerization is to alter the chemical
and physical properties of the fibre.
cotton is held under specified tension for about ten
minutes (no tension, no luster) with an application of
between 19%-26% caustic soda (NaOH) and wetting
agents (used to facilitate the transfer of the NaOH into
the fibers), at room temperature. Then the fabric is
neutralized in an acid bath.
Caustic soda solution swells cotton fibers breaking
hydrogen bonds and weak van der Waal forces
between cellulose chains.

5. The expanded, chains rearrange and re-orient
and when the caustic soda is removed , the
chains form new bonds in the reorganized
state.
When done tensionless, the cotton fiber
swells, the cross section becomes thicker and
the length is shortened. the fabric becomes
denser, stronger and more elastic.
Under tension, The fibers become round and
rod like in cross section and the fiber surface is
smoother, adding to fiber luster.

6. Mercerization types (methods):
1. Slack Mercerization (treatment without tension)
e.g. mercerization with NH3.
2. Tension Mercerization (treatment under tension)
e.g. mercerization with caustic soda.
Definition: Mercerizing is the process of treatment
of cellulosic material with cold or hot caustic alkali
under specific conditions to improve its appearance and
physical or chemical properties.

7. In this process ammonia is penetrate in the fiber
& effect the crystalline and amorphous region of the
fiber and swell them.
Aqueous ammonia can only be disposed off by
shipment to fertilizer plants or other non-textile
process that can use this liquid, or, it must be
recovered in an expensive distillation process for
further reuse.
1- AMMONIA MERCERIZATION (Slack Mercerization):

8. ADVANTAGES OF LIQUID AMMONIA MERCERIZATION:
• Improved strength (up to 90%)
• Enhance luster
• Better dye ability
• Stability to laundering greater thermal resistance

9. WHY LIQUID AMMONIA TREATMENT IS NOT SO POPULAR:
To keep liquid ammonia in liquid form it must stored
below 33 OC.
It forms explosive moisture with air
When leakage in machine it is highly affected to workers.

10. Procedures:
Dipped cotton fabric into a strong and cold
alkaline solution such as lithium hydroxide,
caustic soda, or potassium hydroxide.
The fibers will swell and shrink while still
impregnated in the caustic solution.
They are placed under tension while in this
swollen state and then rinsed with water.
The alkali will be removed and a permanent
round rod and silk-like luster will result.
2-NaOH mercerization (Tension Mercerization ):

11. Fibre level: (swelling, lumen changes from bean
shape to round shape, Shrinkage, etc).
Molecular level: (Breaking of old bonds, Hydrogen bond
readjustment, Orientation (parallelization) of molecular chains in
longitudinal direction and Orientation of the crystalline in the direction of
the fiber length).
Increase in lustre of yarn.
Changes during mercerization process:

12. PHYSICAL CHANGE:
Breaking of old bond
Effect of strong caustic soda (Fibre swollen).
Improved in strength.
Improved in lusture (under tension).
Change in cross section from bean shape to
circular shape.
 Swell and opening of fibre structure.
New bonds are formed upon washing off NaOH.
Increase in the number of OH group.

13. The reactions that take place in mercerization:
The structure is called hydrate cellulose emerges.

14. Chemical change:
Improvement in moisture regain.
Improvement in dye uptake.
On washing and neutralization; the native
cellulose I with concentration of NaOH formed
cellulose II.

16. 1. Cross section of cotton before mercerisation
2-5 swelling process in 18% NaOH
6 Rinsing process after swelling
7 Final state
Change in cross section:

17. Effect of alkali (NaOH)on cotton fibres:

18. ADVANTAGES OF MERCERIZING
The mercerized fibers were able to absorb more water, and
therefore absorb more dye.
colour of the dyed cloth is brighter and deeper.
it also gives the cloth a better resistance to multiple
washings, keeping the colours bright and unchanged over time.
Mercerization treatment increases strength, smoothness,
resistance to mildew, and also reduces lint (protruding).
It also increases luster and affinity to dyestuffs.

19. Types of mercerization’sinstrumentations:
1.Hank mercerization
2.Cheese mercerization
1- YARN
MERCERIZATION
1.Open mercerization
2.Close mercerization
(round & tubular knits
1.Chainless mercerization
2.Chain mercerization
3.Batch-up mercerization
3- CLOTH
MECEREIZATION
2- KNIT
MERCERIZATION

20. HANK MERCERIZATION:
• This is currently the most commonly used method of
mercerization, and generally entails rolling a 54-inch long
(the length of one loop) hank weighing about 500g a number
of times between two adjustable rollers. The yarn is moved
by the turning of the rollers, with penetration of the alkali,
application of tension and rinsing occurring automatically.

21. KNIT
MERCERIZATION:
1. Open Mercerization:
The mercerization involves
treatment of circular knits after
they have been opened, and
fabric that has had its selvage
gummed as required is treated
like a weave.
This method is used in the
mercerization of products with
strict shrinkage restrictions in
both the vertical and horizontal
directions and fabric with motifs
in which skewing often occurs.

22. 2. Closed Mercerization
(Tubular Mercerization)
 This method involves
mercerizing in tubular state.
Knits are usually treated as
two flat pieces of material
which have been laid
together.
 strong tension or pressure
applied longitudinally to the folds
of the two edges of the long sides
of the fabric causes differences in
yarn density on both faces of one
of the knits.

23. 1. Chainless mercerization:
This method is also called roller mercerization. The
machine has a number of stainless rollers and rubber
rollers, of a relatively-large diameter tiered zigzag in close
contact to each other inside a long trough, with the lower
tier designed to submerge in alkaline solution for
mercerization. This type is bound to limited length of
fabric.
A similar device is used for the removal of most alkali
following this initial stage of alkali penetration and fabric
swelling, and an open- width soaping machine for
further removal and neutralization.
Cloth Mercerization:

25. 2. Chain mercerization
A clip stenter is used for post-mercerization treatment, in
which a width wise tension is applied then most alkali is
showered off the fabric kept on the stenter, followed by
thorough alkali removal and neutralization using an open-
width washing machine.
 A heavy padding mangle is used for the application of
alkaline solution in the 2 dip/2 nip method, with sufficient
time allowed for penetration and swelling of the fabric in a
timing cylinder, instead of undergoing an operation using so
many rollers and so much solution as in roller mercerization,
to ensure reduced use of the alkali.

27. 3. Batch-up mercerization:
An alkaline solution is padded onto fabric
which is then rolled up, and when padding is
completed the alkali is removed through
continuous cold rinsing.
Although the use of the method is not
common in Japan, a certain degree of
application, including in knits, can be found in
Western Europe.

28. Test for Mercerization:
1-Barium Activity Number:
It is based on the fabric‘s ability to absorb
barium hydroxide. The procedure is carried
out on the fabric both before and after
Mercerizing.The barium number is calculated using the equation:

29. 2-Deconvolution: cotton hair are cut in large number of
0.2 mm long. They are mounted in liquid paraffin on
microscope slide then counted and the result is expressed as
percentage.
3-Axial Ratio: The changes in dimensions of yarns are due
to the relative positions of the hair in the yarn. Hence, the
lustre of cotton fibres is decided by the ratio between the
long and short axis of the cross section of the cellulose hair.
4-Near Infra Red Spectroscopy: used to understand
changes in hydrogen bonding by observing the exact
wavelengths of the OH stretching vibrations.
5-Infra-red, X-Ray Spectroscopy, etc.