Preparation and Mechanism of SiO2 Aerogel Gypsum Based Materials

Gypsum and its products have excellent performance of heat preservation and insulation, sound insulation, humidity control and fire prevention, and light weight and convenient processing, as an inorganic environmental protection, building material and attention. SiO2 aerogel gypsum slurry was synthesized by building gypsum and SiO2 and aerogel paste by different feeding sequences. The effects of SiO2 aerogel content on the setting time, mechanical properties, contact angle and thermal conductivity of the slurry were studied. Combined with X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) analysis, the mechanism of action between SiO2 aerogel and gypsum was characterized. The results show that with the increase of SiO2 and aerogel content, the water consumption of standard consistency, and dry density of slurry decrease. The contact Angle increased from 51.242° to 122.813°, and the hydrophobicity increased. When SiO2 and aerogel were added, the microstructure consisted of a short columns and a long columns (dihydrate gypsum) packed closely and transformed into irregular sheets (anhydrous gypsum), fine column (dihydrate gypsum) and agglomerated small particles (SiO2) attached to the surface.