Abstract
In the previous study it has been shown that the introduction of acid groups into the rayon fibers is not effective to increase the fastness to washing.
In this study, the effects of hydrophobic groups on the fastness were discussed thermodynami-cally. The effects of the hydrophobic groups and the acid groups when they were coexisting were also discussed similarly.
The results obtained are as follows:
(1) The affinities and enthalpy changes in the partition (C) type adsorption of the dyes are increased with the hydrophobic group content in the rayon fiber.
(2) When the hydrophobic groups and the acid groups coexist, the affinities in the Langmuir's type adsorption of the dye are increased by 2_??_3kcal/mol and the affinities in the C type adsorption of dye are also increased slightly in comparison with the values obtained when only the hydrophobic groups or the acid groups are present.
