Effects of amphoteric copolymer structure on the properties of barium titanate suspensions

The effect of the molecular structure of an amphoteric copolymer, i.e., poly[acrylamide/(ot-N,N-dimethylN-(3-(ß-carboxylate)acrylarnino)propyl) ammonium emanate)] (PAD) on the interactions with BaTiO₃ (BT) particles in water and on the stability of BT suspensions was examined by means of adsorption, ζpotential, sedimentation, and viscosity measurements. The results indicate that the adsorption of PAD onto BT particles follows the Langmuir adsorption isotherm. As the added PAD containing greater ionic group fraction, both the saturated amount of adsorbed polymer and the amount of the polymer required to reach the minimal ζ potential decrease. Whatever the ionic group fraction in PAD, BT suspensions become stable and less viscous when saturated amount of the polymer was adsorbed on particle surface.