Articles
  • Ambient-pressure drying synthesis of high-performance silica aerogel powders by controlling hydrolysis reaction of water glass
  • Sang-Eun Leea,b, Young-Soo Ahna,*, Jin-Suk Leea, Churl-Hee Chob,**, Chang Kook Hongc and Oh-Hoon Kwond
  • a Advanced Materials and Devices Laboratory, Korea Institute of Energy Research, Daejeon 305-343, Korea b Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 305-764, Korea c School of Chemical Engineering, Chonnam National University, Gwangju 500-757, Korea d Department of Chemistry, School of Natural Science, Ulsan National Institute of Science and Technology, 50 UNIST-gil, Ulsan 44919, Korea
Abstract
Silica aerogel powders were synthesized from inexpensive water glass under ambient-pressure drying (APD). Silica sol was synthesized by using adding hydrochloric acid (HCl) to diluted water glass, the silica sol was rapidly formed hydrogel by the addition of isopropyl alcohol (IPA), a new gelation agent. After solvent exchange and surface modification, silica aerogel powders were obtained by ambient-pressure drying the chemically treated hydrogel. This study especially investigates how the amount of added HCl affects properties of the silica aerogel powders, namely the tap density, specific surface area, pore size and volume, microstructure, and hydrophobicity. The aerogel powders size and density were found to decrease and the specific surface area, pore size and pore volume increase with increasing amounts of added HCl. The aerogel powders synthesized with the largest amount of HCl (volume ratio of HCl to water glass: 0.53) showed the tap density, specific surface area, pore size, pore volume, and thermal conductivity of 0.10 g/cm3, 819 m2/g, 12.00 nm, 3.14 cm3/g, and 0.023 W/mK, respectively. Also, it showed good hydrophobicity and thermal stability. It was evident that HCl addition amount can be one of key parameters to control the physical and thermal properties of silica aerogel.

Keywords: Aerogel, Inorganic acid, Alcohol, Water glass, Ambient-pressure drying

This Article

  • 2017; 18(11): 777-782

    Published on Nov 30, 2017

Correspondence to

  • E-mail: