Abstract
Establishment of low temperature dyeing was performed by combining water and some primary alcohols as media for colouration of cellulose acetate fabrics.
It was noticed that increasing the dielectric constant (D) of the dyeing medium caused an increase in the colour strength of the fabrics. This increase was found to be proportional to the time and temperature of dyeing. The colour strength was also further enhanced upon using water/methanol (3:1) and mostly improved in water/n-propanol (9:1) as media for dyeing.
It was seen that the time of half-dyeing (t1/2) and the specific dye-rate constant (k) have increased with increasing the dipole moment of the disperse dyes applied from the aqueous medium to cellulose acetate fabrics. Presence of small amounts of n-propanol as well as increasing the temperature of dyeing lowered preferentially t1/2, and k values. The affinity and heat of dyeing were inter-related with the dipole moment of the used disperse dyes. The affinity was more improved by inducing n-propanol in the dyeing medium and decreasing the dipole moment of the dye, while the heat of dyeing had decreased with addition of n-propanol and increased with increasing the dipole moment. These findings were interpreted in terms of possible disorder of fine structure of the cellulose acetate due to presence of the aliphatic alcohols in its vicinity during dyeing.
