Methacrylamide polymers and copolymers and their alkaline hydrolysis

New evidence bearing on the resistance to hydrolysis of a portion of the amide groups in polymethacrylamide has been obtained through a study of methacrylic acid (M 1 ) — methacrylamide (M 2 ) copolymers. These copolymers were prepared in aqueous solution with potassium persulfate catalyst. The reactivity ratios were found to be approximately r 1 = 2.0, r 2 = 0.3. The ratio of accessible amide nitrogen to total nitrogen was determined for each copolymer and was found to vary from 62.3% for polymethacrylamide to 4.3% for a copolymer containing 4.2 mole % of the amide. Some calculations have been made based upon a semiquantitative statistical interpretation of the suggestion of Arcus that the hydrolysis of polymethacrylamide ceases as soon as each amide group is bordered by two carboxylic ion neighbors and the agreement between observed and calculated ratios offers good support for this theory. The actual mechanism of stabilization by the ion neighbors is still obscure but the chain‐stiffening effect of the α‐methyl groups is believed to play an important role.