Comparison of the ultraviolet blocking effect of knitted fabrics

Skin cancer has one of the highest growing rates among cancer types. Excessive exposure to sunlight is the most important risk factor. The protection offered by textiles against UV radiation is therefore becoming more important. Fiber type used in clothing is one of the most important factors affecting UV protection of that cloth. In this study, the ultraviolet protection of knitted fabrics made of bamboo, soy-bean, cotton and viscose, which are among the most widely used fibers in summer, have been compared. Knitted fabrics made of polyester and cotton/polyester blend were also tested for their ultraviolet protection degree. Polyester knitted fabrics were found to have the highest UPF, while the lowest value belonged to viscose fabrics. All the knitted fabrics were abraded and their UPF values were tested in order to see the effect of abrasion. The fabrics under each group of fiber were produced as slack, medium and tight form in order to see the effect of fabric tightness. The knitted fabrics with higher stitch density and therefore tightness showed higher UPF and lower UV transmittance. The cotton fabrics were wetted, laundered and bleached and their UPF values were tested after each process. Wet samples showed higher transmittance and thereby lower UPF than the dry samples. The bleaching process decreased the UPF values of cotton fabrics. They were also dyed in two different shades in order to see the difference between raw fabrics and dyed fabrics. The dyed fabrics were subjected to abrasion and weathering processes in order to see the degree of change in the UPF values of the fabrics during use. The UV protection considerably increased after dyeing process and darker color gave higher UPF.