One of our research aims is to understand the environmental degradation of fibrous materials. Previous R&D projects have extensively studied the photodegradation and yellowing of the protein fibres wool and silk, and the free radical mechanisms that are involved. Photoyellowing is a serious commercial shortcoming of protein fibres when compared to cotton and synthetics.
In recent years we have being interested in looking at hair damage caused by the UV wavelengths present in sunlight. For unpigmented hair at least, this has many similarities to the processes involved in the yellowing of wool fibres—perhaps not surprising, given that they are both keratinous proteins. We have found that thermal damage can also create free radicals in wool and hair. Developing effective treatments demonstrably capable of controlling both UV and thermal hair damage is an important area for new cosmetic products.
The group has various techniques and protocols available for studying free radicals in protein fibres, including electron spin resonance (ESR), photo-induced chemiluminescence (PICL), and the use of fluorescent probes such as the terephthalate anion to study hydroxyl radicals.
1. K.R Millington and L.J. Kirschenbaum, Detection of hydroxyl radicals in photoirradiated wool, cotton, nylon and polyester fabrics using a fluorescent probe, Coloration Technol., 118, 6-14 (2002).
2. K.R. Millington, Photoyellowing of wool. Part 1: Factors affecting photoyellowing and experimental techniques, Coloration Technol., 122, 169-186 (2006).
3. K.R. Millingon, Photoyellowing of wool. Part 2: Photoyellowing mechanisms and methods of prevention, Coloration Technol., 122, 301-316 (2006).
4. K.R. Millington, M. Del Giudice, S. Hatcher, and A.L. King, The effects of bleaching on the photostability of white fleece wools, J. Text. Inst., 104, 655-660 (2013).