Microwave Assisted Dyeing of Cellulose with Direct Dyes

Abstract

In this research work, dyeing of cotton fabric with direct dyes carried out with exhaustion method by microwave system. The effect of microwave power, time of dyeing, electrolyte concentration, dye concentration and L:G was outlined. The results of preliminary experiments on the effect of microwave on the dye solution and the fabric itself clearly showed that the microwave process has no effect on the cotton fabric and direct dyes. Other results indicated that an increase in the microwave power causes an increase in the dye absorption by the fabric. However the time of dyeing process could also be very effective on the dye absorption. Therefore, extension of dyeing time up to 20 min causes higher exhaustion but further increase in the time of dyeing leads to a decrease in the dyeing absorption. Presence of electrolyte as an absorption ionic material in dyeing process, leads to increase the exhaustion. It can be concluded that the effect of electrolyte and dye concentration in the microwave heating system were similar to the normal exhaustion dyeing. The effects of liquor to good ratio in microwave irradiation were not the same as the normal exhaustion dyeing. Because, the exhaustion increases with increasing of L:G to 100:1 and then decreases in higher L:G. Finally the results of washing fastness showed a small improvement in the washing fastness on the fabric dyed by microwave irradiation.