Mercerisation
Mercerisationis atextile finishingtreatment forcellulosefabricandyarn,mainlycottonandflax,which improvesdye uptakeandtear strength,reducesfabric shrinkage,and imparts asilk-likeluster.
Development
[edit]The process was devised in 1844 byJohn Mercer,[1]who treated cotton with solutions of20–30%sodium hydroxidefollowed by washing. Mercer observed that the treatment shrank the fabric and increased its tensile strength and affinity for dyes. In the original process of Mercer, no tension was applied. The product was termedfulled cotton,a nod to the process offullingin woven wool fabric. Mercer regarded the increased affinity for dyes as the most important technical aspect. Mercer also experimented withsulfuric acidandzinc chloridesolutions and discovered theparchmentisingeffect of sulfuric acid.[2]
The silk-like lustre now commonly associated with mercerising is produced by tension and was discovered byHorace Lowein 1889.[1]
Process
[edit]Treatment with sodium hydroxide destroys the spiral form of the cellulose with formation ofalkali cellulose,which is changed tocellulose hydrateon washing out the alkali. Caustic soda concentrations of 20–26% are used. Effective mercerization requires the use ofwetting agents.[3]
The improved lustre of mercerised cotton is due to the production of nearly circular cotton fibres under tension. Another characteristic feature is the untwisting (deconvolution) of the cotton hair.
In dry mercerization, the process is carried out while drying the fabric on astenter.
References
[edit]- ^abKnecht, Edmund (1911)..InChisholm, Hugh(ed.).Encyclopædia Britannica.Vol. 18 (11th ed.). Cambridge University Press. pp. 150–151.
- ^J. T. Marsh (1948), "Dispersion Processes",An Introduction To Textile Finishing,pp. 111–133
- ^"Textile Auxiliaries",Ullmann's Encyclopedia of Industrial Chemistry(7th ed.), 2007,doi:10.1002/14356007.a26_227
External links
[edit]- Cotton Fabric Mercerizationat theWayback Machine(archived February 2, 2017)