Rapid synthesis of ambient pressure dried tetraethoxysilane based silica aerogels
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BRIEF COMMUNICATION: SOL-GEL, HYBRIDS AND SOLUTION CHEMISTRIES
Rapid synthesis of ambient pressure dried tetraethoxysilane based silica aerogels V. V. Ganbavle1 A. S. Kalekar2 N. S. Harale3 S. S. Patil4 S. L. Dhere5 ●
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Received: 28 February 2020 / Accepted: 29 October 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract Silica aerogel can be produced by using ambient pressure drying (APD) or supercritical drying depending on the required properties and kind of application. Processing time for ambient pressure dried silica aerogels are longer due to the time consuming steps such as hydrolysis and solvent exchange. Considerable decrease in time has been reported by a few research groups by employing shaking during the solvent exchange. We are reporting further reduction in processing time of tetraethoxysilane (TEOS)-based silica aerogel by carrying out the hydrolysis process at elevated temperature. The aerogel obtained in least processing time showed low density (0.066 kg/m3), low thermal conductivity (0.043 W/mK), high specific surface area, and porosity. This shows that elevated temperature hydrolysis does not hamper the desired properties of the product. Graphical Abstract
Keywords
Least processing time Silica aerogel Hydrophobic Mesoporous ●
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* S. L. Dhere [email protected] 1
Dattajiro Kadam Arts, Science and Commerce College, IchalkaranjiKolhapur, 416115, India
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Institute of Chemical Technology, Mumbai 400019, India
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Sadguru Gadage Maharaj College, Dist-Satara, Karad, Maharashtra 415124, India
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Shri Vijaysinha Yadav Arts and Science College, Peth VadgoanKolhapur, 416115, India
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Shri. S. H. Kelkar College, DevgadSindhudurg, 416613, India
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Journal of Sol-Gel Science and Technology
Highlights ● Rapid synthesis of hydrophobic silica aerogels is discussed in detail. ● Ambient pressure drying method used to produce silica aerogels in 16 h 50 min. ● Elevated temperature hydrolysis reduced the processing time without altering properties of aerogel. ● The aerogel obtained in least processing time showed low density, low thermal conductivity, high specific surface area and porosity. ● The aerogel is hydrophobic with water contact angle 140°.
1 Introduction Silica aerogel is a material which possesses extremely low density (~0.05 kg/m3) and it is characterized by low thermal conductivity (~0.005 W/mK), high porosity, and large surface area (~1000 m2/g) [1]. Owing to these properties there is a wide range of applications of silica aerogel monoliths and granules as well in variety of fields such as thermal insulation, oil spill cleanup etc. [2]. Low density silica aerogel monoliths are prepared via supercritical drying process, which in some ways is difficult to carry out due to requirements of high temperature (~250 °C), high pressure (5–10 MPa), and sophisticated autoclaves [3]. The lately developed method of silica aerogel subcritical drying or ambient pressure drying (APD) can be considered to be simpler and inexpensive a
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