Improving the photostability of whitened wool by applying an anti‐oxidant and metal chelator rinse

Millington, Keith R.

doi:10.1111/j.1478-4408.2006.00008.x

Cited by 16 publications

(19 citation statements)

References 20 publications

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“…The behaviour of NAC in showing negligible free radical photogeneration is in agreement with previous work on wool, which showed it to confer a high level of resistance to photoyellowing when applied as a rinse treatment (with oxalic acid) to optically brightened wool . NAC is a powerful antioxidant with several pharmaceutical applications, including use as an mucolytic agent and as the antidote for overdoses of the analgesic paracetamol (acetaminophen) .…”

Section: Resultssupporting

confidence: 88%

“…White hair treated with ascorbic acid (AA) underwent a slow colour change through pink to yellow, which is why there is a large difference in the untreated data for AA-treated hair between Tables I and III. A similar colour change has been observed previously for AA-treated wool [27], and is due to the reaction of the major oxidation product of AA with amino acid residues in the keratin protein. Ascorbic acid would therefore be unsuitable as an additive to protect white or grey hair against photoyellowing, and we cannot use this method to assess its efficacy as a protective treatment.…”

Section: Colour Changes and Photoyellowingsupporting

confidence: 85%

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UV damage to hair and the effect of antioxidants and metal chelators

Millington

Marsh

2020

Intern J of Cosmetic Sci

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Objective To study the effects of addition of a redox metal, copper, antioxidants and metal chelators on the formation of free radicals in natural white Caucasian hair subsequently exposed to UV light. Three different methods, electron paramagnetic resonance (EPR), a fluorescent probe for hydroxyl radical formation (terephthalate) and free radical photoyellowing, were used. These methods utilized different UV sources and reaction conditions, and so can give insights into the different mechanisms of action occurring during UV oxidation of hair. In addition, this study demonstrates how antioxidants and chelators can be screened to determine whether they can protect hair from UV damage. Results The three methods gave somewhat different results, illustrating the importance of reaction conditions and wavelength on the photochemical mechanisms, and the efficacy of additives to influence these reactions. EPR results showed that N‐acetylcysteine (NAC) pre‐treatment eliminated the intensity of the signal because of sulphur and carbon free radicals in white hair both before and after exposure to UVB radiation. Doping the hair with copper ions had no effect on the intensity of the EPR signal under dry conditions. Terephthalate fluorescent probe data showed that under wet conditions, irradiation of white hair with UVA produced significant amounts of hydroxyl radicals. Pre‐treatment of hair with NAC reduced the number of •OH radicals produced by natural white hair compared to an untreated control. In contrast to the EPR result, white hair doped with copper ions produced significantly higher levels of •OH radicals under wet conditions. It appears that the ability of copper ions to catalyse the photogeneration free radicals in hair is highly dependent on water content. Photoyellowing data showed a benefit for oxalic acid but no difference for NAC and an increase in yellowing for EDTA. Conclusion The micro‐EPR and terephthalate fluorescent probe methods are both effective techniques to study production of free radicals by hair exposed to UV light under wet and dry conditions, respectively. Both assays are simple methods for determining the effectiveness of potential protective hair treatments against UV damage, but because they assess free radical damage under dry vs wet conditions, the chemistry created on UV exposure is different. This gives insights into mechanism of action, but results may not be consistent between the two methods for actives added for reduction of UV damage. NAC pre‐treatment did reduce free radical generation in UV‐exposed hair under both wet and dry conditions. Photoyellowing data are more complicated as it is a less direct measure of UV damage and is highly dependent on irradiation source. Using UVB irradiation is experimentally convenient but may not be appropriate, because UVB wavelengths comprise only 0.3% of terrestrial sunlight. The photochemistry of hair exposed to sunlight involves concurrent photobleaching and photoyellowing processes and is far more complex. Under UVB irradiation condit...

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Section: Resultssupporting

confidence: 88%

Section: Colour Changes and Photoyellowingsupporting

confidence: 85%

UV damage to hair and the effect of antioxidants and metal chelators

Millington

Marsh

2020

Intern J of Cosmetic Sci

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“…The use of antioxidants to protect wool from free radical damage that leads to yellowing has been investigated, but no commercial solution has yet been developed. A combination of an antioxidant (N-acetylcysteine) and a metal chelator (oxalic acid), applied as a rinse treatment, was highly effective in decreasing the rate of photoyellowing of FWA-treated wool (170). The treatment was, however, not substantive to the fibers, and the benefits were lost on laundering.…”

Section: Yellowingmentioning

confidence: 87%

Wool: Structure, Properties, and Processing

Rippon

Christoe

Denning

et al. 2016

Encyclopedia of Polymer Science and Technology

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Wool, the fibrous coating from sheep, is the most important animal fiber used by the textile industry. It has been used continuously for several thousand years, the earliest type of fabric made from wool probably being a felt. Although the relative importance of wool as a textile fiber has declined with the increasing use of synthetic fibers, it remains important in some sectors of the market. This article discusses raw wool specification, fiber growth, its complex morphological and chemical structure, and the physical properties that make wool unique among textile fibers. Also discussed are the processing steps used to transform raw wool into consumer products, namely, scouring, carbonizing, carding, spinning, setting, dyeing, bleaching, printing, and treatments to reduce felting shrinkage, insect damage, and flammability. A novel textile fiber made from wool (Optim TM , CSIRO) is also described.

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“…Rinsing FWA-treated wool with low concentrations of an antioxidant such as N-acetylcysteine (NAC) was highly effective against photoyellowing when combined with a metal chelator such as oxalic acid, and provided much better photoprotection than the antioxidant alone, particularly under wet conditions (Millington, 2006a). Unfortunately the benefits of the rinse treatment are lost on laundering, and efforts to identify a substantive antioxidant/metal chelator combination that could be applied during wet finishing and provide effective protection against photoyellowing under both wet and dry conditions have so far been unsuccessful.…”

Section: Methods For Improving the Whiteness And Photostability Of Woolmentioning

confidence: 99%

Improving the whiteness and photostability of wool

Millington¹

2009

Advances in Wool Technology

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Improving the photostability of whitened wool by applying an anti‐oxidant and metal chelator rinse

Cited by 16 publications

References 20 publications

UV damage to hair and the effect of antioxidants and metal chelators

UV damage to hair and the effect of antioxidants and metal chelators

Wool: Structure, Properties, and Processing

Improving the whiteness and photostability of wool

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