a.Oxidative bleaching agents
The double bond breaks in the oxidative bleaching, which makes the substrate colorless,
b.Reductive bleaching agents
Reductive method of bleaching is done with sodium hydrosulphite,sodium sulpfide and sulfur dioxide are powerful reducing agents. Fibres like polyamide, Polyacrylics and Polyacetates can be bleached using reductive bleaching technology.
Double bond is converted into single bond in case of reductive bleaching ,
c.Enzyme aided Bleaching
The use of enzyme technology is attractive because enzymes are highly specific and efficient, and work under mild conditions. Furthermore, the use of enzymes results in reduced process times, energy and water savings; improved product quality; and potential process integration. The process of bioscouring(which remove all non-cellulosic components from native cotton completely or partially.) when combined with bleaching process reduces the process time , cost as well as improves the quality.
for information about enzymes in pretreatment click hereFor More information on Hypochlorites Click Here