Question 16 (Textile Technology & Fibre Science)
During bleaching of cotton with hydrogen peroxide, addition of sodium silicate
| (A) | Reduces the viscosity of bath |
| (B) | Controls the rate of decomposition of perhydroxyl ions (HO2–) |
| (C) | Reduces the surface tension of bath |
| (D) | Enhances swelling of cotton |
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Frequently Asked Questions | FAQs
How do you bleach cotton with hydrogen peroxide? |Does hydrogen peroxide react with cotton? |What is the mechanism of hydrogen peroxide bleaching in textile?
Hydrogen peroxide can be used to bleach cotton through a process called “oxygen bleaching.” Here are the general steps involved:
1)Preparation: First, you need to prepare a solution of hydrogen peroxide and water. The concentration of hydrogen peroxide will depend on the level of bleaching you want to achieve, but typically ranges from 3% to 35%.
2)Soaking: The cotton fabric is then soaked in the solution for a specific period of time, usually ranging from 15 minutes to several hours. The length of time will depend on the concentration of hydrogen peroxide, the desired level of whiteness, and the type of fabric being bleached.
3)Rinsing: After the soaking period is complete, the fabric is rinsed thoroughly in cold water to remove any excess hydrogen peroxide.
4)Neutralizing: The fabric is then neutralized with an acid solution to stop the bleaching process and restore the pH balance of the fabric.
5)Washing: Finally, the fabric is washed with a mild detergent to remove any remaining impurities, and then rinsed again to ensure all the chemicals have been removed.
It’s important to note that bleaching with hydrogen peroxide can weaken the cotton fibers, so it’s essential to follow the proper safety precautions and use the correct concentration and soaking time to avoid damaging the fabric.
What is meant by term bleaching?
Bleaching of cotton refers to the process of removing the natural color of cotton fibers to make them appear white or almost white. Cotton fibers are naturally yellowish in color and can be lightened through the use of chemical agents, such as hydrogen peroxide or sodium hypochlorite, which break down the pigments that give cotton its natural color.
The bleaching process can be done either during the production of cotton fabric or after the fabric has been woven into clothing or other textile products. The degree of bleaching can vary depending on the desired level of whiteness or brightness, and can also affect the strength and durability of the cotton fibers.