Preparation of modified acrylamide polymers

In a process for the preparation of an acrylamide polymer containing hydroxamic groups by reacting an aqueous solution of an acrylamide polymer with a hydroxylamine salt at a mole ratio of hydroxylamine to amide groups in the acrylamide polymer of from about 0.1 to about 2.0, the improvement which comprises conducting the reaction at a pH of at least about 11.0, a temperature ranging from about 40.degree.-80.degree. C., for from about 1-4 hours and at a polymer solution concentration of at least 2%, by weight, the polymer having a molecular weight of from about 10.sup.6 to about 3.times.10.sup.7, said pH being that naturally occurring after substantially complete neutralization of said hydroxylamine salt.