Isopropanol as an air–liquid interface reformer in the processing of cellular silica

Abstract

A novel method for the preparation of ceramic foams with uniform pore and pore size distribution through the addition of isopropanol (iPr-OH) has been discussed. Small amounts of isopropanol were added to silica based aqueous suspensions and the foams were prepared by foam casting method. The rheology of silica based suspensions and properties of the resulting foam are examined and compared with that of samples prepared without iPr-OH addition within similar experimental conditions. Silica foams produced using this novel method displays comparatively higher density, smaller and uniform pores with narrow pore size distribution and significantly improved mechanical strength. The porosity of 79 vol.% and the pore size distribution of 4–25 μm were obtained. The compressive strength of 1.4 MPa with a Young's modulus of 143 MPa was achieved as compared to the low values of compressive strength and elastic modulus of 0.332 and 60 MPa, respectively for the samples without iPr-OH addition.