| Silica aerogel is one of the lightest solid nano-porous materials with continuousthree-dimensional network structure in the world, it has many special properties, suchas low coefficient of thermal conductivity, high specific surface area, low density andso on. Many domestic and foreign researches on silica aerogel are carried out withsilicic acid methyl ester and ethyl orthosilicate as the silicon source and conducted bysupercritical drying process. However, this technology is complex, time-consuming,energy consumption and expensive, these problems can greatly limits the applicationof silica aerogel.In this research, we studied a cheap way to produce silica aerogel. We used waterglass as the silicon source and the aerogel are dried at atmospheric pressure. Thewhole process can be described as sol-gel process, aging process, solvent exchangeprocess, surface organic treatment by trimethylchlorosilane and drying processrespectively. All the factors of these processes such as the concentration of sodiumsilicate solution, pH, drying temperature, the amount of trimethylchlorosilane werediscussed in detail. Experimental results showed that the sodium silicate specificgravity of0.08, in acidic or neutral condition, the sol gel and trimethylchlorosilaneadd quantity for n(TMCS):n(Si)=1, the drying temperature fixed on60℃was the bestexperiment condition. Under this condition, silica aerogel with low density and highpore rate can be achieved.Further more, we produced a kind of composite thermal insulation material bysilica aerogel and glass fibre and studied the technological parameter. This compositematerial can be low costly, high strength with breaking strength of1.5MPa, lowthermal conductivity of0.036W/(m·K), perfect hydrophobicity and excellent fireproofperformance. Computer simulation through ANSYS of the silica aerogel compositethermal insulation material was also discussed. This method can provide thepossibility of computer simulation guiding the actual production. |
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