3.2.4. Effect of dyeing time
The effect of dyeing time was conducted at high concentration
of the dye, i.e. 8 g/100 ml water to reveal the effect of
power ultrasonic on the de-aggregation of dye molecules in
the dye bath as indicated by higher dye-uptake. As shown in
Fig. 5, the colour strength obtained increased as the time increased
in both US and CH methods with much higher colour
strength at all points in the US case. In case of US method,
a plateau is attained after 60 up to 75 min and then started
to decline slightly with prolongation of the time. Whereas in
the case of CH, the decline in colour strength started after
60 min ahead. The decline in the dyeability may be attributed
to the desorption of the dye molecules as a consequence of
long dyeing time.
3.2.5. Effect of ultrasonic power
The effect of ultrasonic power on the dyeability of cationised
cotton fabrics with lac dye was conducted at different
power levels (100e500 W). As shown in Fig. 6, the colour
strength of dyed fabrics seemed to be directly proportional
with the power supplied. This behaviour emphasizes again