Synthesis, characterization and application of reactive UV absorbers for enhancing UV protective properties of cotton fabric

Abstract

TWO colourless reactive UV absorbers 1 and 2 were synthesized by the condensation reaction of both 2,4,6-trichlorotriazine and sulfanilinic acid with 4-aminobenzophenone and ethyl 4-aminobenzoate, respectively. The structures of UV absorbers 1 and 2 were confirmed by IR, NMR (1H and 13C), and elemental analysis. The synthesized reactive UV absorbers were applied to cotton fabric using pad-dry method in comparison with both exhaustion and microwave methods. The results showed that excellent ultraviolet protection factor (UPF) values were achieved on sodium hydroxide-treated cotton fabric using pad-dry method. The optimal conditions using pad-dry method, such as drying temperature, drying time and UV absorber concentration were discussed. It was found that the highest values of UPF and whiteness using reactive UV absorbers 1 and 2 especially after washing can be obtained in the conditions of 80 °C drying temperature, 3 hours drying time and 15 g/l UV absorber concentration. The new reactive UV absorber 1 achieved excellent UPF value (58.2) compared to UV absorber 2 which exhibited poor UPF value (10.5) at the same conditions.