Mercerizing is a treatment for cellulosic material, usually a cotton thread, which strengthens them and gives them a sparkling appearance. This process is less commonly used for linen and hemp yarn.
Video Mercerised cotton
Development
This process was made in 1844 by John Mercer of Great Harwood, Lancashire, England, who treated cotton fibers with sodium hydroxide. The treatment causes the fibers to swell, which in Mercer's version of the process shrinks the overall fabric size and makes it stronger and easier to stain. This process did not become popular until H. A A. Lowe was upgraded to a modern form in 1890. By holding the cotton during the treatment to prevent it from shrinking, Lowe found that the fibers got a sparkling appearance. The process was brought to the DMC company in Mulhouse, France by Jean Dollfus in the 19th century.
Maps Mercerised cotton
Process
Mercerization alters the chemical structure of the cotton fibers. The inter-convert fiber structure of alpha and beta-cellulose blends into cellulose II, a more thermodynamically stable allomorph.
In alpha and beta-cellulose polysaccharide chains are stabilized by intra-molecular hydrogen bonds as well as by hydrogen bonds in the polysaccharide layer.
Between layers are only van der Waals forces in effect. In contrast the crystal structure of cellulose II also has a hydrogen bond between the layers.
Mercerization results in swelling of cotton fiber cell walls. This leads to increased surface area and reflectance, and gives the fiber a softer feeling. The final step that is optional in this process is to skip the thread through an open flame, or singe. It burns wild fibers, improves the appearance of the fabric. This is known as "toxic gas thread" because the gas burner is normally used.
Thread
The modern method of production for merserated cotton, also known as "pearl" or "pearle" cotton, gives cotton yarn (or cotton-coated yarn with polyester core) sodium hydroxide bath which is then neutralized with acidic bath. This treatment enhances luster, strength, affinity for dye, and resistance to fungi. On the other hand, it also increases its affinity for fiber.
Cotton with long staple fiber length responds best for mercerization. Mercerised threads are generally used to produce fine crochet.
References
External links
- The Online Encyclopedia - Mercerizing
- Cotton Fabric Mercerization at Wayback Machine (archived February 2, 2017)
Source of the article : Wikipedia
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