Study on alkaline hydrolysis of polyacrylamide by 13c nmr

Abstract

Alkaline hydrolysis of a polyacrylamide sample was performed in aqueous sodium hydroxide (NaOH) solutions at various NaOH concentrations to investigate the effects of hydrolysis conditions on the sequence distribution of the hydrolyzed products. For this purpose, 13C NMR spectra for the aqueous solutions of the products were measured, in order to determine the sequence distribution based on carboxyl (on acrylic acid residue) and carbamoyl (on acrylamide residue) carbon peak assignments. It was first found that the specific concentration of aqueous sodium hydroxide solution gives a product with a sequence distribution greatly differing from the conventional product whose sequence distribution is almost completely alternative of acrylic acid and acrylamide residues. Under the other hydrolysis conditions employed here, the products with almost alternative sequence distribution were found to be commonly produced. Possible hydrolysis mechanisms are discussed based on the structures of aq NaOH solutions. © 1988 The Society of Polymer Science, Japan.