Mixing and Flow Characteristics in the Alumina/Thermoplastic Resin System

Rheological properties were investigated for combinations of six different alumina and three thermoplastic resins of polyethylene, polypropylene, and polystyrene. The curves of torque versus time in the alumina/resin mixture systems could be classified into four patterns depending on both the mixing properties of each of the resins and the solid concentration. It was verified through infrared spectroscopy and gel permeation chromatography measurements that the behavior of the mixtures could be explained by taking the degradation of each resin into account. Flow was characterized as shear thinning in both the alumina/resin and resin systems. A simple parameter, V¯_p= (ρ_cr? V¯)/ρ_cr, a kind of corrected liquid volume concentration, was introduced to express the dependence of relative viscosity η_r of the mixture on the solid concentration V¯ and the relative compaction density ρ_cr. The relation η_r=αV¯^?β_p could be useful for estimation of the flow properties of ceramic powder/resin mixture systems.