Effect of Polyvinylpyrrolidone on Rheology of Aqueous SiC Suspensions Stabilized with Polyacrylic Acid

The effect of polyvinylpyrrolidone (PVP) on rheology of aqueous SiC suspensions stabilized with polyacrylic acid (PAA) was investigated. At pH 6.0, as the total amount of dispersants was fixed at 0.3 wt%, the suspensions with co-addition of PAA and PVP obtained much lower viscosity than those added separately, displaying Newtonian behavior. The improvement in rheology of SiC suspensions arose from enhanced steric hindrance, which was caused by the presence of PVP molecules in association with PAA molecules adsorbed on SiC particle surfaces. However, this effect was relatively weak in alkaline condition because of complete dissociation of PAA.