EFFECT OF DYE STRUCTURE ON AFFINITY FOR FIBERS 



117 



40 



1,4-DIHYDROXYANTHRAQUINONE 



lOO'C 



SATURATION 



015 



.02 



.03 



C^ MO/ML 



Fig. 1 



Careful physical-chemical analysis of the ethylene terephthalate-dye system 

 shows the fiber is being dyed by a solution mechanism. At eciuilibrium the ratio 

 of dye dissolved in fiber to dye dissolved in water is a constant, equivalent to 

 a partition coefficient. As shown in Fig. 1, an excellent fit of data to a straight 

 line is obtained. The limiting concentrations are those of saturation in both 

 phases. There is no sign in any of the many isotherms we have measured that 

 the dye is associated with specific sites which show a chemical affinity for dye 



Cb M6/ML 



Fig. 2 



