Wettability of Nonwoven Fabrics: Effect of Laundering on Water Absorption

Abstract

The effects of laundering on the wetting properties of nonwoven fabrics have been investigated. Fabric specimens were laundered (washed and dried) 1, 5 and 10 times with steel balls as an agitation source. Most fabrics laundered 5 times showed an increase in water absorption; however, water absorption decreased in the fabrics after 10 launderings. Laundering 5 times influenced the water absorption of regular Tyvek® and unfinished SMS fabrics. The fluorochemical (FC) finished Sontara® and unfinished SMS fabrics showed a slight; increase in water penetration after all levels of laundering; however, the level of laundering did not significantly change the rate of water uptake in the FC finished SMS fabrics. The corona treated Tyvek® exhibited a decrease in water absorption after 5 and 10 launderings. At the maximum number (10) of laundering cycles, the corona treated Tyvek® exhibited the least amount of water uptake among the nonwoven fabrics evaluated in this study. The fiber contact angle and the fabric pore radius, obtained by the Wilhelmy technique, were used for the estimation of the capillary flow rates (based on the Washburn equation). The expected capillary flow rates were plotted against the experimental values of the spontaneous uptake rate from the demand wettability test and from the static absorption test. The results correlated well with the Washburn model. Before laundering, all experimental data were highly correlated with the expected capillary , flow data, such that the relative wettability could be predicted by the Washburn equation. After 5 launderings, the maximum water uptake and the rates of water uptake were not as well correlated with the theoretical capillary flow rates based on the Washburn equation.