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Parale, Vinayak G.,Jung, Hae-Noo-Ree,Han, Wooje,Lee, Kyu-Yeon,Mahadik, Dinesh B.,Cho, Hyung Hee,Park, Hyung-Ho Elsevier 2017 Journal of Alloys and Compounds Vol.727 No.-
<P><B>Abstract</B></P> <P>To improve the high-temperature thermal insulation characteristics of silica aerogels, it is important to reduce the radiative heat transfer. This can be achieved by Y<SUB>2</SUB>O<SUB>3</SUB> doping in the silica sol to opacify the infrared radiation of silica aerogels. The purpose of the present work was to study the effect of Y<SUB>2</SUB>O<SUB>3</SUB> incorporation on the structural and physicochemical properties of opacified silica aerogels prepared by a simple ambient pressure drying method. The influence of Y<SUB>2</SUB>O<SUB>3</SUB> addition on specific extinction coefficient and high temperature thermal insulation of prepared aerogels were investigated. The synthesized aerogels were lightweight and crack-free, with a granular, nanoporous morphology. The specific surface area, pore diameter, and bulk density of the prepared samples were 917.5–937.6 m<SUP>2</SUP>/g, 5.64–6.58 nm, and 0.047–0.076 g/cm<SUP>3</SUP>, respectively. The thermal conductivity of opacified silica aerogel at 1000 K was 0.080 W/(m.K), which was lower than the unopacified silica aerogel and it was around 0.104 W/(m.K) at same temperature.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Low density Y<SUB>2</SUB>O<SUB>3</SUB> opacified SiO<SUB>2</SUB> aerogels by APD for HT thermal insulation. </LI> <LI> Y<SUB>2</SUB>O<SUB>3</SUB> effect on structural, physicochemical and morphological properties of aerogels. </LI> <LI> Aerogels: 917.5 m<SUP>2</SUP>/g surface area, 3.422 cm<SUP>3</SUP>/g pore volume, 6.58 nm pore diameter. </LI> <LI> 0.080 W/(m.K) of thermal conductivity of Y<SUB>2</SUB>O<SUB>3</SUB> opacified aerogels at 1000 K. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Composites of silica aerogels with organics: a review of synthesis and mechanical properties
Kyu‑Yeon Lee,Dinesh B. Mahadik,Vinayak G. Parale,박형호 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.1
Aerogels are considered as outstanding future materials owing to their wide surface area and three-dimensional network of silica particles, low density, low-thermal conductivity, high porosity, and low dielectric property. Their outstanding characteristics represent excellent potential applications in thermal insulation systems, aeronautical domains, environmental clean-up and protection, as heat storage devices, transparent windows, thickening agents in paints, etc. Among these applications, thermal insulating materials can play a vital role in living systems and for saving energy in various domestic and industrial processes. However, native silica aerogels are fragile and sensitive to relatively low pressures, which limit their application. More robust aerogels with higher strength and stiffness can be obtained by compounding silica networks with organoalkoxysilanes, polymers or using porous scaffolds as supports. This paper presents a review on the approaches for mechanical reinforcing methods for silica aerogels and recent achievements toward improving the strength of native silica aerogels. In addition, various characteristics derived from composite aerogels are analyzed synthetically.