Effects of PEG molecular weights on rheological behavior of alumina injection molding feedstocks

The rheological behaviors of alumina injection molding feedstocks containing polyethylene glycol (PEG) binders having different molecular weights were analyzed using capillary viscometer. The results indicate that the feedstock containing larger molecular weight PEG shows a higher yield stress and shear stress. The relative viscosity of feedstocks with PEG binder system is small, which show a good fluidity, and the viscosity decreases with increasing both temperature and shear rate. However, when temperature is above 90 °C, the fluidity of feedstocks with PEG1K and PEG1.5K is too high to catch powder, which may induce dissociation occurring between the binder and the powder particles.