Dyeing Ramie Fabrics With Curcumin in NaOH/Urea Solution at Low Temperature

To improve dyeing properties of ramie fabrics, sodium hydroxide/urea (NaOH/urea) was used as curcumin solvent and ramie-fiber swelling solvent. Ramie fabrics were dyed with curcumin in NaOH/urea aqueous solution at low temperature without using any mordants. The color depth (K/S) value, washing fastness, ultraviolet–visible spectrophotometry were measured to investigate dyeing properties of the ramie with curcumin in NaOH/urea solution at low temperature. Meanwhile, X-ray diffraction and breaking strength were used to determine the structure of the ramie in NaOH/urea solution. Curcumin could be dissolved completely in NaOH/urea solution, and crystallinity of ramie fiber was decreased a little. The K/S value of dyed ramie fabrics in NaOH/urea solution increased around 4-fold compared to dyed ramie fabrics in water. The dyed ramie fabrics in NaOH/urea solution displayed good washing fastness. In addition, dyed ramie fabrics in NaOH/urea solution revealed anti-ultraviolet properties