Journal of the American Ceramic Society, Vol.88, No.3, 524-529, 2005
Dispersion properties of RaTiO3 colloids with amphoteric polyelectrolytes
An amphoteric water-soluble copolymer, i.e., poly(acrylamide/ (alpha-N,N-dimethyl-N-acryloyloxyethyl) ammonium ethanate) (PAAM/DAAE), was evaluated as a novel dispersant for aqueous BaTiO3 (BT) slurries. The dispersing property of this copolymer was examined by means of rheology, sedimentation, particle size, green density, zeta potential, and leached Ba2+ concentration measurements. The results indicate that PAAM/ DAAE could reduce the viscosity of slurries greatly, cause BT particle sizes to shift to smaller values, and make green compacts more consolidated. Compared with a commercial dispersant, ammonium salt of poly(methacrylic acid) (PMAA-NH4), it is as effective or even better in preparing stabilized suspensions. More importantly, PAAM/DAAE could lessen the leached Ba2+ concentration. This is related to the adsorption behavior of this copolymer onto BT particles, and the interaction between the adsorbed dispersant and dissolved barium ions.