What's makes it so colourful?!

We are surrounded by rich diversity of colour everyday in our daily life

We all like to wear colourful clothes whether a special occasion or daily wear.

It's always nice to add a little colour in our lives!

Do you think before if our world are only black and white ???

Clothes, rainbow , flowers , foods only remain black and white.

What kind of life will be?

Hence, colours are very important.

WHAT ARE DYES ?

Dyes are the organic substances that are responsible for turning plain cloth into the colourful garments

that we wear everyday…

Dye molecules are unique.

Each is shaped differently so that it absorbs light in a different way.

Often a third molecule is added to a dye

This acts as a bond between the dye molecule and the molecule of the fabric that the dye is being applied on

SYNTHETIC DYES

Nowadays, there are variety of synthetic acids in used

Today, synthetic dyes are classified by how they are used to dye fabrics

1. ACID DYES

An acid dye is a dye with chemically a sodium salt of a sulphuric, carboxylic

or phenol organic acid.

Acid dyes are highly reactive water soluble dyes that are used to colour fabrics

like silk, wool and nylon.

 It possesses affinity for amphoteric fibers while lacking direct dyes' affinity

 for cellulose fibers

When dyeing, ionic bonding with fiber cationic sites accounts for fixation of

coloured anion in the dyed material.
Acids are added to dyeing baths to increase the number of
protonated amino-groups in fibers.
Acid dyes usually have a sulfo or carboxy group on the molecule making them
soluble in water
Water is the medium in which dyeing takes place.

Most acid dyes are related in basic structure to the following types :

Anthraquinone type

Many blue dyes have this structure as their basic shape

Azo dyes
The structure of azo dyes is based on azobenzene, Ph-N=N-Ph

Mainly used in the dyeing of cotton (cellulose) fibers

most are red in color

Triphenylmethane

There are many yellow and green dyes commercially applied to fibers

2.BASIC DYES

Basic dyes are water-soluble cationic dyes that are mainly applied to acrylic fibers , some use for wool and silk.

Basic dyes possess cationic functional groups such as -NR₃⁺ or =NR₂⁺ 

Basic dyes are used with acetic acid to help uptake of the dye onto the fiber.

Basic dyes perform poorly on natural fibres, but work very well on acrylics!!

Below is one of the examples for the basic dyes

3. DISPERSE DYES

Disperse Dyes are only water insoluble dyes dyeing polyester and acetate fibers.

A disperse dye molecule is based on azobenzene

(as Disperse Red 1 or Disperse Orange 37)

The general structure of disperse dyes is small, planar and non-ionic

with attached poar functional groups like nitro, amine, hydroxyl, etc.

The shape makes it easier for the dye to slide between the tightly-packed polymer chains,

and affect the colour of the dye.

Let shows you the example of disperse dye --------- DISPERSE BLUE 28

SYNTHETIC DYES quickly replaced the traditional natural dyes. 
They cost less and offered a vast range of new colour !!!!

So now are you understand about DYES ?