FLOCCULATING ACTION OF CELLULOSE-DIMETHYLAMINOETHYL METHACRYLATE-ACRYLAMIDE GRAFT COPOLYMERS

Abstract

In order to prepare high-molecular weight (abbreviated as hmw in the text) cationic polymer available as flocculant, both cationic 2-dimethylaminoethyl methacrylate (DM) and nonionic acrylamide (AM) were graft copolymerized onto hydroxyethyl cellulose (HEC). The graft copolymers were then purified by means of fractional precipitation. The flocculating action of HEC-DM-AM graft copolymers was examined in comparison with that of HEC-DM graft copolymers reported in the previous paper1) It was found that: 1) the sedimentation with HEC-DM-AM was faster than that with HEC-DM; 2) in the case of hmw HEC-DM-AM, the larger a molar percentage of AM was, the faster the sedimentation was, though the transmittance was scarcely affected by the DM/AM ratio; 3) the flocculating action of HEC-DM-AM was superior to that of HEC-DM or commercial cationic polymer flocculants, and the suspensions did not tend to redisperse easily at their large dosage, which was distinct from the case of other cationic polymer flocculants. These results lead to the conclusion that effective hmw cationic flocculants can be prepared by means of the graft copolymerization of both DM (10-20 mole-% in the grafted branch) and AM onto HEC.