Effects of surfactants/stabilizing agents on the microstructure and properties of porous geopolymers by direct foaming

Abstract

Colombo (2021) Effects of surfactants/ stabilizing agents on the microstructure and properties of porous geopolymers by direct foaming,

Characterization and Performance Evaluation of Metakaolin-Based Geopolymer Foams Obtained by Adding Palm Olein as the Foam Stabilizer

“…After geopolymerization, a new diffraction hump in the range of 25–30° was detected in the matrix and geopolymer foams. In comparison with MK, a noticeable shift of the diffraction hump center was observed, which is consistent with the literature results [ 43 , 44 , 45 , 46 ]. The hump centered at ~28° can be attributed to the amorphous aluminosilicate gel, the typical binder phase in metakaolin-based geopolymer [ 43 , 45 ].…”

“…In comparison with MK, a noticeable shift of the diffraction hump center was observed, which is consistent with the literature results [ 43 , 44 , 45 , 46 ]. The hump centered at ~28° can be attributed to the amorphous aluminosilicate gel, the typical binder phase in metakaolin-based geopolymer [ 43 , 45 ]. The existence of this amorphous hump coupled with the shift of the hump center demonstrated the occurrence of geopolymerization during geopolymer preparation.…”

“…Some diffraction peaks of anatase (TiO 2 ) and kaolinite are detected. The diffraction band located at 20–25° is attributed to the amorphous phase of MK [ 43 , 44 ]. After geopolymerization, a new diffraction hump in the range of 25–30° was detected in the matrix and geopolymer foams.…”

Taguchi- Grey relational analysis for Optimizing the Compressive Strength and Porosity of Metakaolin-Based Geopolymer

“…The vegetable oils is one of the interesting stablizers because of their low cost and availability. The reaction between highly alkaline solution of geopolymer and vegetable oils, by a saponification reaction, result in the interconnect porous structure [23,24].…”

“…In the current work, three common factors were selected to design the experiments including, the concentration of hydrogen peroxide, the quantity of hydrogen peroxide and the quantity of vegetable oil as stabilizer. These factors were commonly studied in the field of geopolymers and their influnce on the properties of the geopolymer are well documented in many studies [21,24]. Furthermore, for the first time, two additional factors were studied in the current study; these are (i) the time of polymerization elapse before adding the hydrogen peroxide to the produced geopolymer paste prior to casting, (ii) the amount of yeast added to the mix which has been used to catalyze the decomposition of the hydrogen peroxide to produce pores.…”