Flocculation Behaviour of Polymer Brushes of Various Nanostructure

Abstract

Dextran-graft-polyacrylamide copolymers with different backbone lengths and graft numbers have been tested as flocculation aids in model kaolin suspensions. According to the sedimentation rate and the final sediment volume the graft copolymers proved to be rather similar to the linear acrylamide homopolymer having similar molecular weight. According to the supernatant liquid clarity the copolymers are more effective flocculants than the linear polyacrylamide. The supernatant clarity is inversely related to the length of backbone between the grafts. Apparently, conformation of grafted chain is somewhat more expanded in the cases where the grafts are closely disposed. Due to an expanded macromolecular conformation the functional groups of these copolymers are more capable of capturing solid particles than those of linear acrylamide polymers.

Keywords:

• graft length
• kaolin
• macromolecule conformation
• sedimentation rate

Acknowledgments

Thanks to Prof. J.M. Guenet and Dominique Sarazin from Institute Charle Sadron (Strasbourg, France) for light scattering measurements.