In this diploma thesis, the dyeability of cotton woven fabric with the indicator dye methyl orange (MO) was investigated. Dyeing was performed using the conventional exhaust dyeing process. Dyeing of cotton fabric was carried out by two methods, namely, without cationic pre-treatment and with the addition of electrolyte, and with cationic pre-treatment and without the addition of electrolyte in the dyebath. After dyeing, the dyed fabrics were treated with a cationic agent to improve the wet fastness properties of the fabric. The colour of the dyed fabrics and the concentration of the dye in the dyebath before and after dyeing were evaluated spectrophotometrically. The pH sensitivity of the dyed fabrics was also evaluated spectrophotometrically after the dyed fabrics were immersed in the buffer solutions with different pH values. The dyed fabrics were tested for colour fastness to domestic and commercial laundering, to artificial light, to hot pressing and to rubbing. The tests of colour fastness properties and their evaluation were carried out according to SIST EN ISO standards. The results showed that the cationic pre-treatment of the cotton fabric significantly improves the exhaustion of the dye MO onto the cotton fabric. The dyed fabric is sensitive to pH. The wash fastness of the dyed fabric is poor despite the cationic post-treatment. Dyed fabric has good colour fastness to hot pressing, dry rubbing and wet rubbing but very poor lightfastness.
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