Efficacy of selective surfactants/detergents as washing agents on soiled white and dyed cotton fabrics

Four different types of surfactant, namely alkyl benzene sulphonate (A), sodium lauryl sulphate (B), glycerol monostearate (C) and distearyl dimethyl ammonium chloride (D), have been used in single and multiple washing of a soiled white/dyed cotton fabric to determine their critical micelle concentration (CMC) values and to assess their washing performance in terms of changes in some of the physical properties of fabrics, per cent soil removal from soiled white fabric and maximum retention of colour depth of dyed fabric. The washing performance of each surfactant at lower concentration level by multiple wash cycles has also been studied. Wash fastness rating by grey scale and washing performance in terms of retention of colour depth of reactive dye dyed cotton fabric have been assessed and compared by measuring the corresponding KIS values and colour difference values after washing with these surfactants by ISO-II and ISO-III methods. It is observed that the CMC value and the corresponding degree of soil removal at CMC level are 1.9 % and 90.8 % for surfactant A, 1.5 % and 90.6 % for surfactant B, 2 % and 92 % for surfactant C, and 1% and 39.4 % for surfactant D respectively. On multiple wash, the surfactants C and D do not show good performance at lower concentration (0.5-1%), while the surfactant B is found to be better than others. Considering the changes in physical properties of fabrics after washing, washing performance, critical micelle concentration of surfactants and retention of colour depth after washing, the surfactant B shows an overall balanced performance.