Polyoxyethylene di-phosphonates as efficient dispersing polymers for aqueous suspensions

Polyoxyethylenes having a di‐phosphonate functional group at one of their chain ends strongly adsorb on calcium carbonate particles in aqueous colloidal suspensions. An enhanced colloidal stability of such suspensions results with a concomitant drastic reduction of the viscosity of concentrated aqueous suspensions. The viscosity of a 20 wt % CaCO3 colloidal suspension in water could be lowered to 2 mPa · s with low concentrations of polymer. The adsorption and viscosity reduction were studied as a function of the chemical nature of the end chain group and the polymer molecular weight. The di‐phosphonate group was found the most efficient anionic group when associated with a polyoxyethylene of polymerization degree larger than 20. The main features of this di‐block architecture of the polymer are discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65: 2545–2555, 1997