Effects of Ferrous Mordanting on Bleaching of Camel Hair

Abstract

The ferrous mordanting process used for bleaching pigmented fibers has been improved. The serious problems of discoloring and excessive damaging of bleached fibers associated with the deposition of iron during the mordant bleaching process are resolved. All mordanting parameters are critical for successful bleaching of pigmented fibers. When used at a specific temperature and a specific time during mordanting, a reagent (reductive agent or acid) capable of stabilizing the mordant bath (during treatment) produces the most complete reaction of melanin with the iron, while not allowing the iron to be deposited on the keratin. Thus, in the subsequent bleaching process, maximum whiteness is achieved with less damage in terms of the mordanting. Sodium bisulfite can be used as an auxiliary, i.e., at the initial 4.0 pH of the bath, and acetic acid and citric acid can also be applied during mordanting without causing discoloration and excessive damage. The optimum conditions for mordanting are 20°C and 15 minutes when sodium bisulfite is used, and 60°C and 15 minutes with a stabilizer of acetic acid or citric acid. The improved process is, in all respects, superior to conventional processes, with no need for after-treatment with a reducing agent.

Bleaching Process Investigation of Tunisian Dromedary Hair

“…This difference was attended when considering the findings [6,24,25] in this subject. To limit the number of variable parameters, we used the same bleaching process for wool and dromedary hair which both have, initially, the same colour measurement approximately.…”

“…These results show that optimum bleaching time is 30 min in tested conditions. However, an increased bleaching time gives an excessive damage to the bleached fibers [9,16,25]. Indeed, the bleached fibres tenacity is significantly reduced in all cases, particularly at the long bleaching time.…”

Protective Bleaching of Camel Hair in a Neutral Ethanol–Water System

“…Camel hair is normally found in various shades of brown or gray; however, high levels of whiteness are essential for apparel fibers [5]. To achieve white or pastel colours, these fibers must be bleached to selectively decolorize the natural pigment before dyeing [6,7]. Hence, investigations of protein fiber bleaching are of practical as well as academic interest.…”

“…Several methods are known for protein fiber bleaching, and alkaline hydrogen peroxide has become one of the most widely used bleaching agents for protein fibers, such as wool, cashmere, yak hair, and camel hair. The typical process involves pretreatment with a mordant followed by bleaching with hydrogen peroxide under alkaline conditions [6]. Chen et al [8] studied the influence of chlorination followed by mordanting with Fe 2+ and bleaching with hydrogen peroxide on the properties of bleached karakul wool.…”

Influence of Sodium Bisulfite and Lithium Bromide Solutions on the Shape Fixation of Camel Guard Hairs in Slenderization Process

“…It was found [12] that LiBr solution could disorder the microfibrils (crystalline phase) to reach higher entropy while matrix with covalent bonds (mainly disulfide) resists the supercontraction. On the other hand, aqueous NaHSO 3 solution, acting as a reduction agent, was usually employed [4,13] to cleave off disulfide bonds in matrix phase of wools. This can enhance the slippage opportunity of inter -helical molecule chains.…”