Amphoteric water-soluble copolymer for barium titanate slurries. I. Synthesis and dispersing ability



An amphoteric water-soluble copolymer, polyacrylamide/[α-N,N-dimethyl-N-(3-(β-carboxylate)acrylamino)propyl] ammonium ethanate (PAM/DAE) was synthesized and used as a dispersion agent for BaTiO3 particles. PAM/DAE was prepared from acrylamide and [α-N,N-dimethyl-N-(3-(β-carboxylate)acrylamino)propyl] ammonium ethanate in a basic condition through a free-radical polymerization. The structure of this copolymer was verified by IR and 1H-NMR spectra. The dispersing effects of PAM/DAE were examined by measuring the viscosity and sedimentation of BaTiO3 suspensions, and by analyzing the particle size. The results indicate that this copolymer could uniformly disperse the particles, and the resulting suspensions were less viscous, more stabilized, and contained powder with smaller particle size. The dispersing/stabilizing ability of PAM/DAE is close to, or slightly better than, that of a commercial dispersant, ammonium salt of poly(methacrylic acid). © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1443–1450, 2005