Silica aerogel from sugarcane bagasse ash incorporated cementitious thermal insulation composites

Abstract

Silica aerogel was synthesized from sodium silicate solution extracted from sugarcane bagasse ash by sol-gel processing and solvent exchange. The effects of processing parameters, especially the volumetric ratio of trimethylchlorosilane (TMCS) to n-Hexane used to modify the surface of the silica aerogel, were studied. The results showed that the optimal silica concentration to synthesize silica aerogel was 1.0 mol/l with a volumetric ratio of TMCS to n-hexane of 7:50. Silica aerogel synthesized by sodium silicate solution extracted from sugarcane bagasse ash produced a surface area, pore volume, and pore radius of 822 m2/g, 2.69 cm3/g, and 1.70 nm, respectively. Towards development of insulating material, the effects of silica aerogel addition on the microstructure, mechanical properties and thermal conductivity of cement composite were investigated. The results also suggest that the addition of the silica aerogel resulted in a relatively low thermal conductivity of the cement composite of 0.42 W/m∙K.