Acknowledgement

I would like to express my special

thanks of gratitude to my chemistry
teacher Mr. S.L. Jain (M.Sc. B.Ed.)
who helped me throughout this
chemsitry project.

I am grateful for the support and

guidance provided by my teacher
which allowed me to complete this
project on chemistry within the
limited time frame.

I am also thankful to my parents and

friends for their constant
encouragement and cooperation
throughout this period.
 Certificate

This is to certify that “Tushan Jain”

of class 12th A has successfully
completed their Chemistry project on
“Dyeing of fabrics” under the
guidance of “Mr. S.L. Jain”.

_________

Mr. S.L. Jain

 Contents

1. Introduction
2. Objective
3. Requirements
4. Procedure
5. Conclusion
6. Bibliography
 INTRODUCTION

Dyes are colored substances which

can adhere to the surface of
materials and are used to give
color to paper, food- stuffs, and
various textiles such as cotton,
wool, synthetic fibres, silk etc.
For example, alizarin, indigo,
congo red, etc. Chemically, a dye
contains:

i. Some group (such as azo,

indigoid, triphenylmethyl,
anthraquinone, etc.) which is
responsible for the color of the
dye.
ii. Some groups (such as –NH2, -
SO3H,
-COOH, etc) which makes the
dye stick to the fabric by
formation of some salt.
 Dyeing is the process of adding
color to textile products like
fibres, yarn and fabrics. The
temperature and time controlling
are two key factors in dyeing.

The primary source of dye,

historically has been nature, with
the dyes being extracted from
plants and animals.
Since the 18th century, humans
produced artificial dyes to achieve
a broader range of colors and to
render the dyes more stable to
resist washing and general use.

The dyed fabrics appear to be

colored because a particular dye
absorbs radiations of some
specific wavelengths from the
visible region of electromagnetic
radiations which fall
on the surface. The remaining
radiations (complementary colors)
of light are reflected. The color
which we observe is due to the
reflected light.
For example, if a dye absorbs the
light in the wavelength region
corresponding to red, then it
would appear green, which is the
complementary color of red.
Similarly, if a dye absorbs blue
color, it would appear orange.
Methods to apply dye
Dyes are applied to textile goods
by dyeing from dye solutions and
by printing from dye pastes.
Methods include:

1. Direct application
2. Yarn dyeing

Characteristics of a dye
1. It must have a suitable
color.
2. It must be capable of being
fixed to the material.
3. When fixed it must be fast to
detergents, soaps, water, dry-
cleaning solvents, light and
dilute acids.
Types of dye
The dyes are classified by dye
manufacturers for marketing into
the following types:

1. Acid dyes: These are azo dyes

and are characterized by the
presence of acidic groups.
The presence of soluble and
serves as the reactive points
for fixing the dye to the fibre.
They are chiefly used for
dyeing wool, silk and nylon.
For example, Orange I and
Orange II.

2. Basic dyes: These dyes contain

NH2 or NR2. In acidic solutions,
these form water soluble
cations and use the anionic
fabric to sites on the get used
 for dyeing wool, silk and nylon.
For example, aniline yellow,
butter yellow.

3. Direct dyes: These are also

azo dyes and are used to dye
fabrics directly by placing in
aqueous solution of the dye.
These dyes attach to the
fabrics by means of hydrogen
bonding.

4. Disperse dyes: These dyes are

applied in the form of
dispersion of minute particles
of the dye in a soap solution in
the presence of phenol or
benzoic acid. These dyes are
used to dye rayons, Dacron,
nylon, polyesters etc. For
example, celliton fast pink B
and celliton fast blue B.
5. Fibre ractive dyes: These dyes are
linked to the fibre by –OH or –NH2
group present on the fibre. These
dyes induce fast color on fabrics
which is retained for a longer time.
These dyes are used for dyeing cotton,
wool and silk.

6. Insoluble dyes: These dyes are

directly synthesized on the fibre. The
fabric to be colored is soaked in an
alkaline solution of phenol and then
treated with a solution of diazotized
amine to produce azo dye. The color
induced by such dyes is not so fast.
These dyes are used for dyeing of
cotton, silk, polyester nylon, etc. For
example, nitroaniline red.
7. Vat dyes: These dyes are water-
insoluble and before dyeing these
are reduced to colorless compounds
in wooden vats by alkaline reducing
agents. The fibre is then soaked in
the solution of the dye. Fibre is then
exposed to air or an oxidizing agent.
By doing so the colorless compound
gets reoxidized to colored dye on the
fabric. For example, indigo.
8. Mordant dyes: These dyes are
applied after treating the fabric with
precipitates of certain substances
(mordant material) which then
combines with the dye to form a
colored complex called lake. Some of
the mordants are salts of aluminium,
iron and tannic acids. Depending on
the mordant used, the same mordant
dye can give different colors and
shades. For example, alizarin gives
red color with aluminium and black
violet with iron mordant. Mordant
dyes are used for dyeing of wool, silk
and cotton.
 OBJECTIVE
To dye wool and cotton with
malachite green.

REQUIREMENTS
500 ml beakers, tripod stand,
wire gauze, glass rod, spatula,
wool cloth and cotton cloth.

Chemicals required: Sodium

carbonate, tannic acid, tartaremetic
acid, and malachite green dye.
 PROCEDURE

1. Preparation of sodium carbonate

solution: Take about 0.5 g of
solid sodium carbonate and
dissolve it in 250 ml of water.

2. Preparation of tartaremetic
solution: Take about 0.2 g of
tartaremetic and dissolve it in
100 ml of water by stirring
with the help of glass rod.

3. Preparation of tannic acid

solution: Take 100 ml of water
in a beaker and add about 1.0 g
of tannic acid to it. Heat the
solution. On heating a clear
solution of tannic acid is
 obtained.

4. Preparation of dye solution:

Take about 0.1 g of malachite
green dye
and add to it 4oo ml of water. On
warming a clear solution of the
dye results.

5. Dyeing of wool: Take about

200 ml of dye solution and dip
it in the woolen cloth to be
dyed. Boil the solution for
about 2 minutes. After that
remove the cloth and wash it
with hot water 3-4 times,
squeeze and keep it for drying.
6. Dyeing of cotton: Cotton does
not absorb malachite green
readily, therefore it requires the
use of a mordant. For dyeing a
cotton cloth dip it in sodium
carbonate solution for about 10
minutes and then rinse with
water. Then put the cloth in
hot tannic acid solution for
about 5 minutes. Now take out
the cloth from tannic acid
solution and keep it in
tartaremetic solution for about 5
minutes. Remove the cloth and
squeeze it with spatula to remove
most of the solution. Now place
the cloth in boiling solution of the
dye for about 2 minutes. Remove
and wash the dyed cloth
thoroughly with water, squeeze
and keep it for drying.
7. Dyeing of cotton directly: Take
another piece of cotton cloth and
pit it directly into boiling solution
of the dye. Keep it dipped for
about 2 minutes. Remove the
cloth, wash with water, squeeze
and keep it for drying. Compare
the color of this cloth with that
dyed by using mordant.
 OBSERVATIONS

1. The color of wool cloth dyed

directly by dipping in hot
solution of malachite green
dye is fast.
2. The color of cotton dyed cloth
directly (without using
mordant) by dipping in hot
solution of malachite green is
not so fast to washing and is
of low intensity.
3. The color of cotton cloth
dyed indirectly by using
mordant and then by
dipping in hot solution of
malachite green is fast to
washing and is of high
intensity.
 BIBLIOGRAPHY

1. Comprehensive practical
chemistry (class 12)
2. www.wikipedia.org/wiki/Dyeing
3. Gemini AI
4. Library
5. Chemistry textbooks
6. Chemistry practical lab