EFFECT OF DYE STRUCTURE ON AFFINITY FOR FIBERS 



125 



ACID DYES 



HOjS-QfX " 



HO-C-/~^ 



QUINOLINE YELLOW 



8O3H 



HO, 



HOjS-O-N'-N-t) 



FAST RED E 



8O3H 



CH3 



SO3H 



NH— (S- 



ANTHRAOUINONE GREEN 6 



NH 



CH3 



Fig. 14 



purposes only under conditions most favorable to absorption of anion; i.e., at 

 low pH where the tiber is completely protonated. 



There is an interesting relationship that can be developed for the adsorption 

 of anions on cationic sites in wool or nylon. In general as the mass/charge ratio 

 is increased (for example, the organic portion of the molecule containing a single 

 sulfonic acid is enlarged), the afifinity of the dye increases sharply. Equilibrium 

 distribution of color between fiber and bath is changed in favor of fiber. This is 



AFFINITY OF ANIONS FOR POLYAMIDES 



u. 

 b. 



< 



ASSOCIATIVE 



IONIC 



MASS / CHARGE 



Fig. 15 



