On the relationship between fabric processing and ultraviolet radiation transmission

The relationship between a fabric's physical characteristics and ultraviolet radiation transmission has been widely discussed in the literature. However, very few studies have taken into account the 'fiber-fabric construction-processing' history of fabrics into consideration to fully elucidate the ultraviolet (UV) protection abilities of fabrics. This study reports the effect of fabric processing treatments, both chemical and bio-chemical, on the transmission of UV radiation (UVR) through selected white and undyed fabrics. Eight woven fabrics were selected to illustrate the effect of chemical processing on UVR transmission. Fabrics were characterized with respect to fiber chemistry, fabric construction, weight, thickness, and chemical processing history. Influence of fabric characteristics and processing on Ultraviolet protection factor (UPF) were studied. Furthermore, a knit bleached cotton T-shirt fabric was treated bio-chemically and the effect of bio-chemical processing on UPF was investigated. Physical characteristics of fabrics such as thickness, weight and cloth cover were shown to be only partly useful in explaining the UV protective abilities of fabrics in that the data show anomalies when only physical features of fabrics are considered without considering processing history. However, by taking into account the processing history of fabrics, the UPF values obtained can be fully explained. Chemical processing methods such as desizing and bleaching have a deleterious effect on UV transmission through fabrics. Bio-chemical processing such as the use of enzymes is comparatively benign and does not adversely impact the UV protective ability of cotton fabric.