Development of Geopolymer Foams for Multifunctional Applications

Abstract

Due the increasingly stringent environmental regulations and sustainable development-induced pressures to increase efficiency, the world faces new challenges. For this reason, the production of structural materials with controlled properties has become urgent. Due to their excellent mechanical and chemical properties and energy-efficient production methods, geopolymers have remarkable potential in higher value-added applications. This potential application exceeds their historical use as environmentally friendly substitutes for Portland cement. The aim of the present research is to produce metakaolin-based geopolymer foams using the combined technique of saponification/peroxide decomposition/gel casting. Concerning physical properties, the effect of H2O2 concentration, the type and amount of stabiliser and the addition of slag were investigated. XRD, FTIR, SEM, CT and thermogravimetric analyses were performed to characterise the material structure. Multifunctional geopolymer foams were developed that can be made free of organic matter and cracks through the optimisation of technological parameters (heat treatment, washing and firing). Such high strength (8.9 MPa), lightweight (~499 kg/m3) and low thermal conductivity (~0.041 W/mK) foams can be used as thermal insulating materials to reduce the energy loss of buildings. Due to their high open porosity (~77.7 vol%) and specific surface area (~4.3 m2/g), foamed geopolymers can function as catalyst supports in many physicochemical applications.

Keywords

• foamed geopolymer
• combined foaming process
• controlled physical properties
• structural characteristics
• multifunctional applications
• thermal insulating material