Wetting characteristics and surface energy properties of cellulosic and noncellulosic fibers

Surface wetting characteristics affect textiles in both application and manufacturing process. Most studies of dynamic wetting behavior of single textile fibers have been done on large-diameter round filaments. Relatively little work has been published on the wetting behaviors of cellulosic fibers. Availability of the wetting data on these fibers is important as they represent the materials most widely used for imbibing and absorbing fluids. In this investigation, surface characteristics of several different fibers, including cotton, Galaxy and regular rayons, cellulose acetate, wool, polyester, and polypropylene fibers were examined. The variables investigated were fiber type, cross-sectional shape, denier, and finishes.; The first task accomplished was to develop a new sample mounting technique which produced reproducible values of wetting force. To convert these to values of contact angles, perimeters of fibers were determined by SEM analysis of cross-sections. The wetting force tests on single fibers was conducted with an electrobalance at speed of immersion of 750 {dollar}rmmu m/min{dollar} using a new sample mounting method and the Wilhelmy technique. The surface energy was calculated from the values of contact angles measured with two dissimilar liquids whose dispersive and polar contributions to surface tension were known.; The results showed that wetting characteristics of various fibers were not dependent on size or shape, but were dependent on the type of fibers and the finish applied. Among the fibers studied here, the wettability decreased in the following order: Galaxy rayon (maximum), cotton, regular rayon, cellulose acetate, wool, polyester, and polypropylene (minimum). The durable finish on cotton did not produce a noticeable change in wettability, but oleic acid finish decreased wettability. The wettabilities of polyester and wool decreased noticeably after treatment with fluorochemical and silicone finishes, respectively.; Since higher surface energy leads to higher wetting force, Galaxy rayon which had the lowest contact angle also had the highest surface energy. The presence of durable press finish on cotton did not change surface energy significantly. Oleic acid finish on cotton decreased the polar component and increased the dispersion component. The surface energy decreased considerably after treatment of polyester with fluorochemical finish and wool with silicone finish.