ABSTRACT
In recent years, consumers are showing more concern on the need of protection from sun rays and ultraviolet (UV) radiation that may induce skin damage from excessive exposure. In this context, UV-protective textiles are important in our daily life, as about 6.1% of the total solar emission reaching the Earth is composed of UV radiation. The remaining percentages in the emission spectra are a mixture of visible light (51.8%) and infrared (42.1%) radiation. The average photon energies in the infrared, the visible light, and the UV light of the solar emission are 63, 200, and 315-400 kJ/mol, respectively. Due to the lower wavelength and higher photon energy of UV rays (UVRs) compared to the two other components, its penetration ability into the top layer of the skin is also high, which may cause acute and chronic diseases, such as acceleration of skin ageing, sunburn, blotches, wrinkles, weak immune system, suntanning, photocarcinogenesis, skin cancer, eye damage, and DNA damage. UV radiation is categorized into three zones based on their wavelength, namely, (1) UVC (200-280 nm), getting mostly absorbed in the ozone layer of the upper atmosphere; (2) UVB (280-320 nm), which penetrates the top layer of the skin and may cause skin ageing, sunburn, etc.; and (3) UVA (320-400 nm), which penetrates through the skin and may cause skin ageing.1 Therefore, for an effective UV protection, the textile has to be designed and nished in such a way so as to block the transmission of both UVA and UVB, as they are capable of penetrating the human skin. The UV-protective performance of a textile is dened by the ultraviolet protection factor (UPF), and a UPF of ≤10 for a textile is considered as providing no protection
6.1 Introduction .......................................................................................................................... 113 6.2 UV Radiation and Its Impact ................................................................................................ 115 6.3 Evaluation of UV-Protective Performance ........................................................................... 116 6.4 UV and the Sun Protective Textile ....................................................................................... 118
6.4.1 Effect of Fiber and Fabric Properties ....................................................................... 119 6.4.2 Effect of Color .......................................................................................................... 119
6.5 Traditional UV-Protective Finishing of Textile .................................................................... 120 6.6 UV-Protective Finish Using Nanotechnology ...................................................................... 122
6.6.1 UV Protection Using ZnO Nanoparticles ................................................................. 123 6.6.2 UV Protection Using TiO2 Nanoparticles ................................................................. 125
6.7 UV-Protective Finishing Using Plasma ................................................................................ 128 6.8 Sustainable UV-Protective Finishing of Textile ................................................................... 129
6.8.1 Sustainable UV-Protective Textile Using Plant Extract ........................................... 129 6.8.2 Sustainable UV-Protective Textile Using Nanoparticles of Natural Polymers ........ 132 6.8.3 Sustainable UV-Protective Textile Using Natural Polymer ...................................... 133
6.9 Summary .............................................................................................................................. 134 References ...................................................................................................................................... 134
from UV radiation. On the other hand, if the fabric has a UPF of ≥50, it is considered to be an excellent UV-protective textile. The fabric’s ability to protect from UVRs is dependent on several parameters, such as ber type and additives, constructional characteristics (e.g., weave, ends and picks/unit length, thread count, cover factor [CF]), the nature and depth of the color applied, the presence of an optical brightening agent (OBA), pigments or nishing agents, launderings and washing conditions, stretch, and moisture.
