Cationic Pretreatment for Reactive Dyeing of Cotton and its Simultaneous Antibacterial Functionalisation

Reactive dyes are chemically bonded to a cotton fibre surface. The anchor groups of dye molecules initiate this covalent bonding. In addition to this anchor group, reactive dyes also contain charged functional groups that are often negatively charged sulphonate groups -SO3-. These negative groups are part of the dye to enable its solubility in water. In industrial applications, dyes are applied as part of a water-based dye bath. The aim of the presented study was to improve the dyeing of cotton through the cationic modification of the textile, supporting an attraction to negatively charged dye molecules. In this way, the dye up-take and achieved colour depth should be improved. The current study was performed with a vinyl sulfone reactive dye. Three different nitrogen containing cationic organic substances were used for cotton pretreatment. In addition to colour properties, the antibacterial properties of prepared textile samples were also studied because antibacterial properties are often related to compounds containing amino and ammonium groups. Finally, it was shown that the cationic pretreatment with two of the three studied agents increased the dye up-take of cotton fabric from the dye bath. At the same time, one cationic agent can introduce antibacterial properties to treat cotton fabrics against two different types of bacteria: E. toll and S. warner!. The simultaneous application of a functional property during an optimised dyeing process was demonstrated in this case and can serve as an example for further applications.