Scouring of Wool:
Wool fibre contains 20-50% impurities like dirt, dust, vegetable matter, wool grade, dried sweat etc.

Wool is a protein fibre and sensitive to base. It can be scoured by using detergent at pH up to 7  at 60oC.  The detachment of  oil from wool by the action of detergent are shown below in the figure:    

     Carbonization: The vegetable impurities from the wool is removed using carbonizing process.In this process wool is treated with sulfuric acid. Wool is resistant to acid and vegetable matter dissolves in the sulfuric acid.

Detachment of Oil by the action of detergent

Scouring of Silk:

Silk is a protein fibre and consists of solidified fluid excreted from the glands of silk worm. When the silk worm is matured it consists large number of these glands. The liquid comes out from each glands in the form of fine stream and as soon it comes in contact with air it is solidified in the form of fine filament. The filament are wrapped in the oval shape due to spinning of the silk worm during the excretion of the fluid. This is known as silk cocoon in which silk worm (as shown in the adjacdent figure) eventually get enclosed.Silk cocoon may contain 300 meters of silk multi -filaments. 

For getting around 100g of silk, 1000 cocoons are required. Spinning of cocoon takes 304 days. When this process is completed the silk worm get converted into pupa (as shown in the adjacdent figure) which remains inside the cocoon. The silk filament is surrounded by natural gum known as silk gum. Both silk and gum are protein. Seracin is silk gum protein and fibron is silk fibre protein. Seracin is more amorphous and easily attacked by chemicals.   

There are four varieties of silk. These are Mulberry, Tussar, Eri and Muga. Mulberry is a cultivated silk while others are wild silk.

Following is the composition of Mulberry silk:

i) Fibroin: 70-75%

ii) Sericine: 25-30%

iii) Waxy substances: 2-3%

iv) Naturak colours: 1-1.5%

v) Mineral matter: 0.5-1%

The gum content in various varieties are given below:

• Mulberry silk: 25-30%
• Tussar: 5-15%
• Muga:7-10%
• Eri: 3-5%

Degumming of silk:

Just boiling with water in the presence of detergent, removes silk gum (Sericine).  The presence of  sericene acts as protective coating during weaving, thus improve weaving performance. Therefore it is removed after weaving to make it dyeable. If the gum is not removed following problems are observed:

-No lustre

-Brown colour

-Harsh feel

After removal of gum, silk become very shiny and soft to feel. 

For degumming of silk, silk is treated with olive oil soap 25% on weight of material at 90-95 degree Celsius for 1-2 hours followed by washing with hot and cold water to remove hydrolysed gum. After degumming  silk lost around 25-30% weight. 

The degumming of silk can also be carried out using Protease enzyme. It breaks  peptide/amide linkage of gum and converted into simple amino acids.