MSc Students Presentations - KONSTANTINOS PAPAPETROS

Cotton is the predominant natural product in the textile industry. One of the most demanding procedures, is the dyeing of cotton textiles with reactive dyes. The traditional methods of dyeing leave a significant environmental fingerprint due to the disposal of dye and saline residues. High concentration of electrolytes is used, such as sodium chloride, in order to balance the surface charge of fiber and the anionic parts of dye molecules. Achieving high modification and dyeing efficiency, while keeping a low cost and eco-friendly processing, can both be achieved by modifying the cotton’s surface with multi-functional polymers.

The present study focuses on the physicochemical characterization of the cotton substrates’ modification with water solutions of multifunctional cationic modifiers, in order to achieve charge inversion of cotton fabrics’ surface. In this way, the use of electrolytes during the dyeing process can be avoided or reduced and, consequently, the process can be carried out at room temperature. The study of the required processes from the substrate pre-treatment to the final dyeing, is performed through molecular spectroscopy (Raman-IR) and surface atomic analysis using X-ray Photoelectron Spectroscopy (XPS). The characterization of industrially pre-treated substrates can also be achieved by using X-ray diffraction (XRD) in order to control the bleaching/mercerization process and the purity of the cotton substrate. Finally, the possible interactions between the polymeric modifier and the dye molecules have been studied by using both molecular spectroscopy and XPS.

After all, this dyeing procedure is characterized as more efficient and eco-friendly, as (a) the dyeing waste (b) the need of energy for a higher temperature process and (c) the use of electrolytes has been eliminated.