Interaction and dispersion stability of alumina suspension with PAA in N,N′-dimethylformamide

The alumina suspension in N,N′-dimethylformamide (DMF) was studied in the presence of a polyacrylic acid (PAA) dispersant. The sedimentation measurements of the suspensions show that PAA can impart favorable dispersion stability to alumina in DMF over a wide apparent pH (pHa) range. The adsorption of PAA on alumina and the zeta potential of the suspension are pHa dependent. FTIR-ATR spectroscopic studies reveal that the different interaction mechanisms between PAA and alumina work as a function of pHa. But the observable difference of dispersion between pHa values of 2.6–12.7 is small according to the sedimentation experiments. This can be explained by a combination of the static effect of PAA dispersant and different sizes of steric barrier resulting from the configurational variation of PAA with changing pHa values.