A Microscopical Study of Residual Oily Soil Distribution on Fabrics of Varying Fiber Content

Abstract

Microprobe techniques were used to study the distribution of residual triolein, a major constituent of human sebum, within yams of varying fiber content. Fabrics of acrylic, polyester, nylon, cotton, and polyester/cotton were soiled with triolein, aged for 16 hours at 38°C, and washed at 38°C with a heavy-duty, unbuilt liquid detergent. After five soil-age-wash cycles, specimens were prepared for analysis by electron microscopy. For fibers of all chemical types, backscattered electron images and electron beam X-ray microanalysis showed high concentrations of triolein in the interfiber capillaries of the yarns and on the fiber surfaces. Oil appeared in beads on the surfaces of acrylic and nylon fibers and on polyester fibers from the polyester/ cotton blend that had a durable press finish. Unfinished polyester fibers, both round and trilobal, had a more uniform coating of oil around the fiber surfaces. Radiotracer analysis indicated that less residual oil was present on the nylon fabric than on the fabrics containing other synthetic fibers. The distribution of oil, however. was similar for these fabrics. Little or no triolein was observed in the interior of any of the synthetic fibers. Cotton fibers had large deposits in the crenelated surfaces and in the lumen, as well as in the interfiber spaces. Dewaxed cotton fabric retained 10% less triolein than the cotton fabric that had not been extracted with an organic solvent. The 50% polyester/50% cotton fabric with a durable press finish had a lower amount of residual oil on it than the unfinished fabric. '