Cationisation of cotton fabrics using various methods and evaluation of the contributions of these methods to sustainable textile production

Cotton fibres have no affinity for many dyes and require significant amounts of electrolyte during dyeing. However, the intensive use of electrolytes during reactive dyeing results in the production of significant amounts of waste water. To overcome this challenge, cotton is cationised with cationic agents, enabling it to be dyed with anionic dyes without the use of electrolytes. This study is a doctoral thesis conducted as part of a joint project between Pamukkale University and Ozanteks Tekstil Company, one of Turkey's leading towel and bathrobe manufacturers. The present thesis employed two distinct methodologies. The initial method is comprised of two different sections. In the initial section of the study, 100% cotton towel fabrics were subjected to cationisation during and after the bleaching process in a laboratory conditions. This was accomplished by utilising six distinct commercial cationisation agents. Subsequently, the cationised 100% cotton terry towel fabrics were subjected to dyeing processes, including salt-free and traditional reactive and acid dyeing. The CIELAB values, rubbing and wash fastness, and colour strength (K/S) values of the cotton Terry towel fabrics were then compared. Subsequently, an analytical hierarchical process (AHP) was conducted to determine the most suitable cationisation agents and processes for large-scale commercial applications. In the second part, the results of large-scale commercial cationisation, reactive, and acid dyeing processes using the selected cationisation agents and processes were presented. Following the implementation of a commercial-scale dyeing process, a comprehensive analysis was conducted on the cotton towel fabrics. The analysis encompassed the evaluation of colour strength (K/S) values, physical properties (tensile strength, stiffness and water absorbency), and colourfastness properties (washing, perspiration, water, and rubbing fastness). Furthermore, a study was conducted on the environmental impacts of commercial-scale cationisation and dyeing processes. This study analysed the following parameters in the context of the dyeing processes under investigation: ammonium nitrogen (NH4+), chemical oxygen demand (COD) values, total water consumption, chemical consumption, and energy consumption. In the second part of the study, the cationisation of cotton fabrics used for bed sheets, a significant home textile product, was examined using the pad-batch method, and their subsequent dyeing. A statistical comparison was made of the CIELAB values, rubbing and washing fastness, and colour strength (K/S) values of treated cotton sheet fabrics.