Ceramic Foams

The present study demonstrates the interaction of starch and surfactant in alumina slurry during foaming and consolidation. Starch based alumina slurries were foamed by using non-ionic (Triton X) & cationic (CTAB) foaming agents. Foaming tendency of surfactants in presence of starch was evaluated from extent of foaming of slurries and surface tension measurement of aqueous solutions of surfactants and starch. Gelation properties of starch, in presence of surfactants were evaluated from oscillatory and swelling power measurements. Coupled effect of both foaming and gelation in alumina slurries were studied from the porosity measurement and microstructure of alumina foams. Triton X found to be better in terms of controlling porosity and uniform microstructure. Microstructure analysis, extent of foaming, gelation behavior and surface tension of aqueous solutions confirmed the existence of interaction between CTAB and starch. The interaction was due to hydrogen bond formation between ammonium ions of CTAB molecule and ¿OH group of amylose unit present in starch was confirmed from FTIR spectra.