A novel method for natural dyeing of cotton fabrics with anthocyanin pigments from Morus rubra fruits

A novel pathway to improve the substantivity of anthocyanin pigments from Morus rubra fruits onto cotton fabrics is proposed by preparing and applying an anionic agent (sodium, 4-(4,6-dichloro-1,3,5-triazinylamino)-benzenesulfonate) to fabrics. Successful modification of cotton fabrics with few negative effects was carried out and evidenced by the results of Fourier transform infrared spectroscopy, tensile strength and the whiteness index. The optimum amount of anionic agent was identified to be about 70 mg/g under the following conditions: 20% (owf) anionic agents, 1:20 material-to-liquor ratio, 100 g/L sodium sulfate, 30℃ for 60 min and pH 11.0. A temperature of 40℃ and a time of 60 min were found to be the optimal conditions for cotton fabrics dyeing with anthocyanin pigments. Dyed cotton fabrics had a shade of brilliance and saturation red with acceptable fastnesses for potential commercial applications. The influences of pH and temperature on the stabilities of the extracts were also investigated.