Effect of Plasma on Dyeability of Fabrics

The unique physical and chemical characteristics of the plasma environment make it attractive for textile processing. Plasma is an ionized gas, i.e. it contains electrons, ions and neutral atoms and/or molecules. However, not all of the ionized gases used in textile processing will exhibit the properties associated with plasmas, mainly because of their low charge state densities compared to the neutral gas density or are produced by transient phenomena. Plasma activation is being used in several fabric and nonwoven applications in the textile industry. (Pane et al., 2003) There are many industrial applications of thin film deposition by plasma sputtering or plasma polymerization in the technical textile and nonwoven industry. Roughly, the coatings deposited in those industries can be categorized under either (permanently) hydrophilic coatings or hydrophobic/oleophilic coatings. In most cases, the deposited coatings give rise to unique products that are difficult or even impossible to produce using other technologies. The textile market is trying to make deep, dark colours and this is not easy to achieve. (Svensson, 2004) One way to do this is to reduce the specular component of reflection of the fabric surface after dyeing. A plasma etching leads to a controlled nano or micro-roughness, increasing diffuse reflectance and minimizing the specular component. In consequence, the dyed fabric will have an intense darker colour after plasma etching. In various research programs, it has been shown that pick-up of dyestuff can be strongly improved after plasma pre-treatment of natural and synthetic fibre fabrics. Polypropylene fibers have such excellent properties as low specific weight (0.91 g/cm3 only), high strength (42-53 CN/ Tex) and good resistance to acids and alkalis, and they also possess good thermal resistance and antibacterial properties. The poor wettability (only 0.05 % at 20 oC) and dyeability have, however, limited the application of these fibers in garments and other industries (Huang et al, 2006). It is of importance to improve the wet ability and dyeability of PP fabrics for many applications. Although chemical modification of the fibers has been somewhat successful in improving hydrophilic and antistatic properties, there are environmental concerns related to the disposal of chemical after