Synthesis of cationic flocculant by radiation‐induced copolymerization of methyl chloride salt of N,N‐dimethylaminoethyl methacrylate with acrylamide in aqueous solution. II. Copolymerization at higher monomer concentration

The radiation‐induced copolymerization of methyl chloride salt of N,N‐dimethylaminoethyl methacrylate with acrylamide was studied to prepare a polymer flocculant that can be handled as a solid. The product obtained in the presence of 5–20% water was a solid and could be ground to a powder without drying. In order to obtain a water‐soluble polymer at a higher concentration, the effect of various additives on the copolymerization was investigated and found that alcohols bearing a hydrogen atom attached to the tertiary carbon atom effectively inhibit intermolecular crosslinking to give water‐soluble polymer. It is suggested that the formation of water‐insoluble polymer is predominantly attributable to the crosslinking of polymer chains rather than to the imidation of amide groups. Copolymerization in the presence of isopropyl alcohol as inhibitor of the crosslinking was also studied and compared with that reported previously, which was carried out at a lower monomer concentration without additives.