Abstract
"Geopolymer" is the general name for an alkali aluminosilicate polymer. The effects of the Si/Al molar ratio and alkali species (K or Na) on the solid-phase formation and of syneresis (water evaporation) on the formation of microporous geopolymer were investigated. The sizes of the constituent particles decreased from the micrometer to nanometer scale as the Si/Al molar ratio increased, and the decrease in particle size was accompanied by the concentration of interstitial pores approximately 50 nm in diameter between the particles. K-type geopolymer possessed an aggregated structure of small spherical particles, whereas Na-type geopolymer had an aggregated structure of large, irregularly shaped particles. The size and number of pores increased by syneresis as the water ratio increased; however, moderate syneresis decreased the size and number of pores.
