Synthesis of an amide/carboxylate copolymer for barium titanate suspensions. I. As a dispersant

An anionic copolymer, that is, poly[methacrylamide-co-(ammonium methacrylate)] (PMMN), was synthesized for the purpose of application to barium titanate (BT) suspensions. The chemical structure of the prepared polymer was verified with IR and ¹H-NMR spectra. PMMN has the potential to have a double function of dispersant and binder for BT suspensions because it contains both amide groups, which are expected to bring a binder contribution, and carboxylate groups, which are expected to bring a dispersant contribution. In this article, the dispersion effects of PMMN with different monomer ratios are examined and evaluated through viscosity and sedimentation measurements. The results indicate that this polymer could uniformly disperse the particles and make the resulting suspensions less viscous and more stabilized. PMMN with a methacrylamide/ammonium methacrylate ratio of 60/40 appears to be most effective, as this polymer induces sufficient electrostatic forces among particles when it is adsorbed onto BT powder.