Abstract
The effects of sodium lauryl sulfate on the adsorption of monosulfonated acid dyes (Metanil Yellow, Orange II, Roccelline and Alizarine Saphirol SE) on Nylon-6 are studied. The adsorption of dye acids of four acid dyes and lauryl sulfate on Nylon-6 are examined respectively, and the affiinities for Nylon-6 are determined.
The affinities of Metanil Yellow, Orange II, Roccelline and Alizarine Saphirol and lauryl sulfate are -16.6, -15.0, -19.0, -14.9 and -16.3 kcal/mol respectively.
In dyeing of Nylon-6 with dye acid of four dyes in presence of SLS, the difference -(Δμ°D-Δμ°s) between affinities of dye acid (-Δμ°D) and lauryl sulfate (-Δμ°s) are determined, where that lauryl sulfate competes with dye ion for the positive sites on the fiber, and the differences coincide to the results of dyeing with single dye acids except Roccelline.
In order to suggest the effect of SLS in acid dyeing, the reciprocal of adsorbed amounts of dye on Nylon-6 (1/[D]φ) are plotted to the concentration of SLS in dyebath ([S]σ).
It is found that 1/[D]φ is proportional to [S]σ, theoretically and experimentally. The slope of line plotted 1/[D]φ to [S]σ corresponds to the retarding effects of SLS, and the slope is found to. increase according to the decrease of affinity of dye acid on Nylon-6.
