Concentrated graphite suspensions in aqueous polymer solutions.

The present paper reports the interactions of several polyacrylamides having high molecular weight and variable content of ionizable groups with concentrated colloidal suspensions of graphite spherical particles. The method of electric conductivity dispersion with frequency has shown that within the range of small KCl concentrations, the adsorbed polymer layer expands, and it then contracts, with the increase of ionic strength. The KCl concentration, at which the contraction of polymer begins, decreases with molecular weight at the same hydrolysis degree and with the increase of hydrolysis degree for the same molecular weight. The expansion of the adsorbed layer increases with number of hydrolyzable groups on the chain and with the amount of adsorbed polymer. [ABSTRACT FROM AUTHOR]