Synthesis and characterization of silica aerogels by a novel fast ambient pressure drying process |
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Authors: | Fei Shi Lijiu Wang Jingxiao Liu |
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Affiliation: | aBuilding Materials Research Lab, Dalian University of Technology, Dalian 116024, China;bDepartment of Materials Science and Engineering, Dalian Institute of Light Industry, Dalian 116034, China |
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Abstract: | Using cheap waterglass as silica source, silica aerogels were synthesized via a novel fast ambient drying by using an ethanol/trimethylchlorosilane (TMCS)/Heptane solution for modification of the wet gel. One-step solvent exchange and surface modification were simultaneously progressed by immersing the hydrogel in EtOH/TMCS/Heptane solution, in which TMCS reacting with pore water and Si–OH group on the surface of the gel, with ethanol and heptane helping to decrease the rate of TMCS reacting with pore water and extrude water from gel pores. The synthesized silica aerogel was a light and crack-free solid, with the density of 0.128–0.136 g/cm3 and 93.8–94.2% porosity. The microstructure, morphology and properties of the aerogels were studied by FTIR, SEM, TEM and BET measurement. The results indicate that silica aerogels exhibit a sponge structure with uniform nano-particle and pores size distribution. The specific surface areas of silica aerogels are 559–618 m2/g. And there is an obvious Si–CH3 group on the surface of the silica aerogel. |
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Keywords: | Waterglass Ambient pressure drying Silica aerogel One-step solvent exchange/surface modification |
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