Bubble behaviors in chemical direct foaming process and effects on pore structures of geopolymer foams

Abstract Geopolymer foams (GPFs) are considered potential candidates for the highly porous ceramics owing to their high porosity and simple synthesis. In this study, bubble behaviors during different phases of the foaming process and their effects on the pore structure of molded GPFs were examined. The foaming reaction characteristics in a foaming system containing H 2 O 2 were adjusted based on variables, such as catalyst content, temperature, activator‐to‐precursor ratio, and surfactant content. The viscosity of the slurry was also measured under different experimental conditions. Bubble behaviors were determined by characterizing the change in the gas volume in the slurry and the pore structure of the molded GPFs. Different pore structures will be realized by adjusting the relationship between the extrusion effect and liquid film properties in the various foaming phases.