Poly(maleic acid) – A novel dispersant for aqueous alumina slurry

Poly(maleic acid) (PMA) was investigated as an anionic long chain dispersant for the preparation of highly loaded aqueous alumina slurry. Suspensions with 1 wt% alumina powder were prepared through variation of PMA concentrations at pH 9 to assess its dispersion efficacy in aqueous medium. Addition of PMA increased the stability of 1 wt% alumina suspensions as evidenced by higher zeta potential and RSH (relative suspension height). 55 vol% alumina slurries were prepared with different PMA concentrations at pH 9. Based on the rheological studies, 3.8 mg of PMA per gram of alumina was obtained as the optimized dispersant amount at pH 9. All the slurries had shear thinning behavior and the slurry with optimum dispersant amount had insignificant thixotropy. Further, adsorption of dispersant was evident by Fourier transform infrared spectroscopy (FTIR) analysis and thermogravimetric analysis (TGA). The slurry at pH 9 with optimum dispersant amount had lowest viscosity and easy flowability. Microstructure of bisque fired and sintered body by SEM microscopy revealed homogeneous particle distribution and uniform grain growth with sintered density of 3.94 g/cm3. The mechanical property evaluation revealed that the samples prepared with optimum dispersant amount had the flexural strength of 483 ± 22 MPa.