Abstract: A polyamine having the formula: H2N—A[NR—B]aNH2 or salt thereof, wherein A and B, which may be the same or different, are selected from aliphatic or aromatic substituents provided that at least four carbon atoms separate any two nitrogen groups, R is an aliphatic or aromatic group, and a is 2 to 5. In addition, a polymer having the formula: or salt thereof, wherein A, B and Q, which may be the same or different, are selected from aliphatic or aromatic substituents provided that at least four carbon atoms separate any two nitrogen groups, R is an aliphatic or aromatic group, a is greater than 1 to about 5, and n is 3 to about 1,000. The polymers are useful for improving acid-dyeability of polymer compositions, fibers, fabrics, films and other articles.