Synergistic effect of copolymer and poly(vinylpyrrolidone) mixtures on rheology of aqueous SiC suspensions

With the addition of poly(vinylpyrrolidone) (PVP) as a second dispersant, the rheological behaviors of SiC suspensions dispersed with copolymer acrylic acid/2-acrylamido-2-methylpropane sulfonic acid sodium (AA/AMPS) in both acid and neutral condition were further improved remarkably. In the presence of PVP with small amount (0.1 wt%), yield stress of SiC suspensions was much lower than that dispersed with only AA/AMPS, and co-addition mode resulted in much higher stability of suspensions than sequential addition modes. The improvement on rheological measurement might derive from enhanced steric hindrance due to the formation of hydrogen bonding between adsorbed AA/AMPS and PVP, as supported by FTIR.