Adsorption of cationic dye by poly(vinyl alcohol) fiber treated with sulfuric acid.

When acid groups were introduced in poly (vinyl alcohol) (PVA) fibers by treating with 20_??_30% sulfuric acid at 74°C for 90 minutes, they were dyeable with cationic dyes. The acid groups of PVA introduced by this treatment were stable in neutral or alkaline condition, but the most of them were unstable in acidic one. From these results, it was assumed that the most of acid groups in PVA treated with sulfuric acid were sulfuric ester types and adsorbed cationic dyes.