Sustainable bulk scale cationization of cotton hosiery fabrics for salt-free reactive dyeing process

Salt-free reactive dyeing is the need of hour in textile reactive dyeing industries to overcome the problems posed by salt usage. A cationic agent (CA) namely 3-chloro-2-hydroxypropyl trimethyl-ammonium chloride was used to cationize the cotton fabric. At present cold pad batch method is used to fix the cationic agent to fabrics. In the present work, exhaust method of application of cationic agent to knitted cotton goods at an industrial level is proposed. The reaction mechanism and effect of materials to liquor ratio, the molar ratio of NaOH to cationic agent, the temperature on dyeing performance are discussed in detail. The cationization process was optimized based on the colour strength of the cationized cotton fabric dyed with the Black GDNN reactive dye at 7% shade which is widely used for knitted fabric processing in India. Various analytical tools such as Fourier transform infrared spectroscopy and field emission electron microscope with energy dispersive X-ray analyser were used to characterize the efficiency of the cationization process. The change occurring in molecular and supermolecular level due to the cationization process is discussed in detail. (C) 2017 Elsevier Ltd. All rights reserved.