Dispersing Multi-Component and Unstable Powders in Aqueous Media Using Comb-Type Anionic Polymers
Abstract:We have investigated the effect of polymeric dispersants on the rheological properties and consolidation behavior of concentrated cemented carbide (WC–Co) and magnesia (MgO) suspensions. The relatively novel types of comb-type anionic polymers with grafted non-ionic side chains are effective dispersants also in multi-component powder mixtures with a complex solution and surface chemistry and result in more robust suspensions at significantly higher solids loading compared with e.g., a traditional cationic polyelectrolyte. Direct force measurements on comb-type dispersants with different lengths of the grafted ethylene oxide side chains showed that the dispersants adsorb onto a MgO surface and infer a repulsion where the range scales with the length of the poly ethylene oxide side chains. The compressibility and the consolidation behavior of MgO particle networks in response to a centrifugal force field could be related to the estimated thickness of the adsorbed comb-type dispersants.
Document Type: Research Article
Affiliations: 1: YKI, Institute for Surface Chemistry, Stockholm, Sweden 2: Sandvik Tooling AB, Stockholm, Sweden 3: Department of Civil Engineering, Technical University of Denmark, Lyngby, Denmark 4: Materials Chemistry Research Group, Department of Physical, Inorganic and Structural Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden
Publication date: June 1, 2006