Ultraviolet Protection Factor of Gray-state Plain Cotton Knitted Fabrics

The protection provided by clothing against ultraviolet (UV) radiation has been the subject of considerable recent research. However, a lack of investigations concerned with the influence of yarn properties on UV protection capabilities of fabrics seems to be present. This study investigated the influence of yarn twist and surface geometry on these properties of fabrics. The gray-state plain cotton knitted fabrics were produced from yarn differing in twist level under controlled conditions, so as to obtain as similar as possible construction of the fabrics. These plain knitted (single jersey) fabrics were spectrophotometrically assessed and UV protection factor was calculated. The results obtained indicated that yarn twist to a great extent influenced the UV protection properties of the knitted fabrics through the influence on yarn compactness and surface properties, which in turn influenced the open porosity of the fabric. The results were also interpreted as the consequences of minimal differences between knitted fabrics' construction (different stitch density), which could not be avoided because of the yarn twist differences.