Thesis Details

Thesis Title: An investigation of factors that influence the degree of ultraviolet protection provided to the human skin by 100% cotton knit apparel
Thesis Author: Robert Habeb
Abstract: Skin cancer caused by ultraviolet radiation (UVR) has increased rapidly in recent years, largely caused by the depletion of the ozone layer in the earth's atmosphere and lifestyles which involve more time outdoors. Fortunately, apparel can be used effectively to prohibit UVR from contacting the human skin. This study investigated several factors that influence the ability of a textile material to protect the wearer from harmful ultraviolet radiation. Specifically, the effects of two UV absorbers and their concentrations, fabric construction, dye type, shade depth, and laundering on the UVR protecting ability of 100% cotton apparel were evaluated. Also, the influence of type and concentration of UV absorber on fabric color was evaluated. Results of this investigation indicate that the cellulose-reactive UV absorbers generally improved the ultraviolet protection offered by the bleached and lightly dyed 100% cotton apparel fabrics. However, additional factors in the pad-thermofix finishing process used in the research served to counter these improvements. Additionally, the Solartex 4589 UV absorber from Ciba Specialty Chemicals Corporation was identified as generally providing more protection than Clariant Corporation's Rayosan CO for bleached and lightly dyed fabrics. The ability of the Solartex product to absorb radiation throughout the ultraviolet region and into the visible spectrum produced markedly visible shade differences in especially the bleached fabrics. The concentration of UV absorber did not generally demonstrate a significant effect on the ultraviolet protection offered by the fabrics. Also, the results of this study typically showed no significant difference in the ultraviolet protection provided by the C.1. Reactive Blue 220 and C.1. Reactive Red 239 dyes. However, dye depth was generally shown to significantly affect ultraviolet protection, with greater depth providing increased protection. Fabrics treated with 3.0% dye provided sufficient UV protection to override any improvements obtained by applying the UV absorbers. In the greige state, the fleece knit construction provided greater ultraviolet protection than did the single jersey fabric. In most cases, laundering significantly improved the ultraviolet protection provided by the 100% cotton fabrics, to an order resembling the improvement achieved by applying the UV absorbers to the fabrics. With few exceptions, both UV absorbers were shown to produce a visible color difference in the single jersey fabrics to which they were applied at both 1 % and 2 % concentrations based on the dry fabric weight.