Polymeric stabilization of fused corundum during nanogrinding in stirred media mills

This paper deals with the steric stabilization of fused corundum during milling in ethanol and water. Different molecular weights of DAPRAL, a block copolymer with lyophilic and lyophobic side chains, were used to stabilize the feed material particles during wet grinding. Preliminary studies of the adsorbed amounts of the polymer in different solvents were determined by TGA and by rheology measurements in order to select sufficient amount of polymer to stabilize the suspension. The median particle size of sterically stabilized milled alumina particles was obtained via Dynamic Light Scattering, Ultrasonic Extinction, BET and SEM. In this investigation primary median particle sizes of 60 nm were obtained in ethanol by applying the steric stabilization mechanism. The mechanochemical characterization was carried out on the milled alumina particles and a phase transformation from alumina to aluminum hydroxide in water was observed, irrespective of stabilization mechanisms. However, no phase transformation was observed in ethanol.