The effect of the molecular weight of polyethylene glycol on the microstructure of freeze-cast alumina

Soluble polymers are frequently used in freeze casting of ceramics to improve the structural integrity of the unfired ceramics. This study examined the effect of the molecular weight of polyethylene glycol (PEG) on the sintered microstructure of freeze-cast porous alumina ceramics. Increasing the molecular weight was shown to reduce the measured pore size from 10 μm to 5.5 μm, with the observed trend being qualitatively consistent with the effects of molecular weight on the diffusivity of PEG and constitutional supercooling.