Plasma Pretreatment for Polymer Deposition-Improving Antifelting Properties of Wool

Wool substrates of fibers and fabrics were treated with nitrogen plasma under atmospheric pressure or subject to chlorination followed by a polymer deposition process for improving the antifelting property. The antifelting property of wool fibers was assessed by a felting ball test, which revealed that plasma treatment alone could achieve the best antifelting effect, but the hand feel was adversely affected. With the deposition of the polymer on the fiber surface, the antifelting properties were retained with an acceptable hand feel. There was a great improvement in the wettability of the chlorinated and plasma-treated wool fabrics after being qualitatively assessed by wetting time when compared with an untreated fabric sample. The wettability was further quantitatively evaluated through the contact angle measurement with different solvents. The test results showed that the contact angles were reduced implying that the wool surface became more hydrophilic. The SEM pictures showed that a relatively rougher surface was observed for the plasma-treated wool fiber when compared with the chlorinated wool fiber. In addition, X-ray photoelectron spectroscopy (XPS) analysis revealed that there was an increase in oxygen and nitrogen contents of both the chlorinated and plasma-treated wool fibers, which might improve the hydrophilicity of the wool fibers. When the two different surface treatments were compared, the plasma treatment could alter significantly both the physical and chemical surface properties as confirmed by SEM and XPS analyses. However, the chlorination could only alter the surface chemical composition. In conclusion, the improved hydrophilicity of the wool fiber surface by nitrogen plasma could enhance and achieve a better polymer deposition on the wool fiber surface for improving the antifelting properties of wool when compared with the chlorination process.