Roles of polymeric dispersant charge density on lead zirconate titanate aqueous processing

Poly(acrylic acid) (PAA) and poly(acrylic acid-co-maleic acid) (PACM) were used as dispersants in preparation of lead zirconate titanate (PZT) aqueous suspensions. The effects of dispersant structure on particle stabilization were investigated through properties of the suspensions. Viscosity and sedimentation height measurements showed that addition of the dispersants improved particle stabilization. The dispersant concentrations to obtain the lowest viscosity were 0.4 wt% for PAA and 0.2 wt% for PACM based on powder dried weight basis. Furthermore, effects of pH were studied on the suspensions prepared with 0.2 wt% dispersants. Viscosity and sedimentation behaviors indicated the improvements of particle dispersion and suspension stability with an increasing pH. Particle dispersion revealed by laser light scattering and scanning electron microscopy supported an improvement of particle dispersion at alkaline pHs. Detailed analysis of these data indicated that the PACM exhibited higher dispersant efficiency for PZT aqueous suspension in all conditions. The results were discussed based on the concentrations of anionic –COO− groups at various pHs and charge density along polymeric backbone of the dispersants.