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

Abstract

As conventional bleaching under alkaline conditions is chemically damaging to protein fibers, a three-stage protective bleaching process in neutral ethanol-water mixtures was proposed for camel hair using mordanting with ferrous salts, oxidative bleaching with hydrogen peroxide, and reductive bleaching with sodium hydrosulfite. The aim of this work was to improve the whiteness degree of camel hair without substantial tenacity loss. In addition, the roles of ethanol during the bleaching treatment were also examined by characterizing the fibers using scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and X-ray diffraction. The whiteness degree and mechanical properties of camel hair bleached in the neutral ethanol-water system were significantly superior to those of fibers bleached by a conventional method. SEM images showed no visible cracks on the scales of fibers bleached in the ethanol-water system, whereas large grooves were observed on fibers bleached in aqueous solution. TEM images confirmed the positive influence of ethanol on the mordanting process, and FTIR spectra suggested that ethanol reduced the breakage of hydrogen bonds in the fibers during the oxidative bleaching process. These findings indicate the potential of this protective bleaching method for application to a broad range of other natural protein fibers.

An efficient ultrasonic-assisted bleaching strategy customized for yak hair triggered by melanin-targeted Fenton reaction

“…The crystallinity of yak hair showed almost no change after bleaching confirmed by their similar typical diffraction pattern of α-keratin with a prominent 2θ peak around 10° and a broad peak around 22° ( Fig. S6 b) [33] . Previous research proofed that ultrasonic treatment does not affect the wool crystallinity property [34] , [35] , however may change the crystallinity of cellulosic fibres [36] .…”

Utilization of Waste Leather Powders for Highly Effective Removal of Dyes from Water

“…The first stage of degradation (stage-I), between 35 and 120 °C, can be attributed to water evaporation and small molecular substances. The second stage of degradation (stage-II), between 120 and 800 °C, is associated with the decomposition of peptide bonds [34,49]. As depicted in Figure 5c, the weight loss of the absorbed water, bound water, and small molecular substances in CL was about 8.5% (stage-I).…”

Ação da água do mar artificial nas características da fibra capilar submetida a descoloração e coloração

“…A oxidação química (descoloração) provoca o clareamento da cor natural do cabelo devido à oxidação da melanina presente no córtex (HARRISON;SINCLAIR, 2003). O método mais frequentemente utilizado para este procedimento, envolve o uso de uma solução alcalina de peróxido de hidrogênio a 12%, com pH entre 9 e 11, contendo outros intensificadores, tais como persulfato de amônio ou persulfato de potássio (GARGANO et al, 2018;XIA et al, 2018). De acordo com os resultados apresentados pela avaliação de cor do grupo (Laranja), foi possível perceber mudança pouco perceptiva em quase todas as mechas, quando comparadas ao grupo (Azul), indicando que essa alteração foi mais visual do que em números.…”

“…O acúmulo de tais perturbações na estrutura química do cabelo, se traduz em modificações em níveis estruturais mais elevados e afeta a aparência, a textura, a força e o brilho do cabelo. Para minimizar estes efeitos é aconselhável o uso de condicionadores, tanto na solução de descoloração como após este processo (SANCHES, 2019;GROSVENOR, et al, 2018;XIA et al, 2018;RYU et al, 2016).…”