Influence of the amount of absorbed moisture in nylon fibers on atmospheric pressure plasma processing

During atmospheric pressure plasma treatment, the existence of moisture in the substrate material may have a potential influence on the treatment effect. In this study, nylon 6 fibers with three different moisture regains (1.23, 5.19 and 9.70%) were treated by atmospheric pressure plasma jet were investigated to improve the wettability and dyeing properties of fibers. The scanning electron microscope showed that at 9.70% moisture regain, the surface layer of the fibers was partially peeled off after plasma treatment. X-ray photoelectron spectroscopy analysis indicated that the plasma-treated fibers had higher oxygen concentration than the control fibers. In dynamic contact angle measurement, the advancing contact angles of all three treated groups decreased about 12°, while the groups with 5.19 and 9.70% moisture regains had lower receding contact angles than the group with 1.23% moisture regain. Using acid dye and dispersive dye, respectively, greater dye uptake was observed in treated fibers whereas the dye depths of the two dyes in nylon fibers were not affected by plasma treatment. The dyeability of the treated fibers with 1.23% moisture regain was a little better than that of the other two treated groups. In addition, no significant difference in single fiber tensile strength was found among control and treated fibers.