The fabrics were dyed at a liquor ratio of 40:1, with the dye
bath being maintained at different pH (2–7). The temperature was
raised to different temperatures (60–100 ◦C) over 30 min and held
at this level for 60 min. The dyeing was carried out in laboratory
dyeing machine (Ahiba Datacolour International, USA). Then, the
dyed fabrics were removed, rinsed with water, followed by soaping
step using 3 g L−1 of a non-ionic detergent at 60 ◦C during 5 min.
Finally the fabric samples were washed thoroughly with cold water,
squeezed and dried at room temperature.