Turmeric dyeing and chitosan/titanium dioxide nanoparticle colloid finishing of cotton fabric

Abstract

The possibility of combining the finishing and natural dyeing of cotton fabric has been studied using a single-stage, paddry-cure technique, by treating it with chitosan/titanium dioxide nanoparticle colloids and turmeric dye. Differentparameters have been studied to optimise the process, such as the chitosan/TiO2 nanoparticle colloid concentration, citricacid crosslinker concentration, sodium pyrophosphate catalyst concentration, dye concentration, pH, curing time, andtemperature. To investigate the effects of combined treatment on the dyeing and functional properties of the treated cottonfabric, its ultraviolet protection factor, antibacterial activity, self-cleaning properties, rigidity, colour strength (K/S), fastnessbehaviour, nitrogen content, and wettability are determined. In addition, the cotton fabric surface is characterised usingscanning electron microscopy. The samples treated with chitosan/TiO2 in the presence of citric acid exhibit excellentprotection against ultraviolet radiation as well as antibacterial activity. The optimum conditions are 0.75% TiO₂ (w/v), 10% dye (w/v), 2.5% chitosan (w/v), 30 g/L citric acid, 4 g/L sodium pyrophosphate, 70°C drying temp. and 5 min drying time,180°C curing temp. and 2 min curing time. The results also indicate the efficiency of the treatment in improving the selfcleaningproperties of the fabric. A significant improvement in the colour fastness is observed for the treated fabrics.