Application of polyamidoamine dendrimer in reactive dyeing of cotton

Cotton is dyed very extensively using reactive dyes. Conventionally, reactive dyeing requires voluminous amount of electrolyte and alkali for dyeing of cellulosic fibres like cotton. But the consumption of electrolyte for reactive dyeing of cellulosic textiles increases the pollution load in the textile wastewater. Moreover, there is a possibility of reactive dye hydrolysis in presence of alkali which is detrimental but unavoidable. Therefore, an attempt has been made to eliminate the use of electrolyte and alkali by modifying the cotton substrate with different generations of PAMAM (polyamidoamine) dendrimer using exhaust and continuous method of application. Subsequently, dyeing was carried out by exhaust method without using electrolyte and alkali. The dyed samples were tested for wash fastness, light fastness and rubbing fastness. Colour strength in terms of K/S was also assessed. The results were comparable to those for dyeing obtained by conventional exhaust method. Therefore, the proposed method demonstrates a promising alternative to the conventional dyeing method by completely eliminating electrolyte and alkali.