以Pickering Emulsion 方法製備三水鋁石多孔材料

Abstract

This study prepares porous gibbsite foams by Pickering Emulsion. We use gibbsite as the main component, sodium dodecyl sulfate as forming agent and surfactant, carbon chain alcohol, dodecanol, i.e., as the stabilizer to buffer the electric charge of SDS surfactant. First, by changing the SDS concentration into gibbsite slurry, the surface potential is measured by Zeta Potential Analyzer. Results reveal that surface potential is decreased when SDS concentration is increased. And, because of dodecanol, the experimentally determined CMC is lower than theoretical CMC value. When the concentration of SDS is 6mM, we obtain the lowest surface potential at 25mV, and the slurry is stable when SDS concentration is above 8mM. From TEM analysis, a well dispersed gibbsite morphology is observed with SDS comparing to the agglomerated gibbsite before ball-milling. From optical method, bubble size is observed with time, the bubble is stable when SDS concentration is greater than 6mM. In the second part, corn starch, agar solution and SiO2 are added into gibbsite slurry respectively as binder. From contact angle analysis, corn starch can become a binder to stabilize gibbsite foam when the corn starch content is greater than 13vol%, and the contact angle for stabilized bubble is 60-67o；the contact angle for SiO2 addition is 50-60o and for agar solution is 50o. These all reveal that, gas is formed in water foam. Pore distribution, porosity and morphology are characterized by mercury intrusion porosimetry and FESEM, The porosity is 75-90%. Finally, three point bending test reveals the bending strength in range of 80-300kPa and indicates the bending strength is decreased with increasing of porosity and median pore diameter