Improvement of the silica aerogel strengthening process for scaling-up monolithic tile production

Rigacci, Arnaud; Einarsrud, Mari‐Ann; Nilsen, Elin; Pirard, René; Ehrburger‐Dolle, Françoise; Chevalier, Bruno

doi:10.1016/j.jnoncrysol.2004.06.042

Cited by 39 publications

(18 citation statements)

References 16 publications

(22 reference statements)

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“…When silica-gel was reinforced by TEOS solution, silica with large mesopores was prepared. For example, BJH surface area, pore volume and pore diameter (PD) for 100SiO 2 Although the Ostwald ripening effect to strengthen a gel surface is often described [12][13][14][15][16][17][18][19], our results suggest that the thorough removal of water in the inside of the gel and the gel skeletal reinforcement are essential for making large mesopores. Figure 4 shows the conceptual scheme of the gel skeletal reinforcement.…”

Section: Catalytic Cracking Reactionmentioning

confidence: 72%

“…[12][13][14][15][16][17]. In the preparation of these materials, supercritical or subcritical conditions [12][13][14][15][16] and alkoxysilylation [14,15] or methylsilylation [17][18][19] are used to inhibit the extensive shrinkage of large pores at the removal process of entrapped solvent from the wet gel. In particular, alkoxysilylation and methylsilylation are promising methods because they can produce aerogels at ambient pressure by inhibiting rapid hydrolysis and the successive condensation which leads to pore shrinkage.…”

Section: Introductionmentioning

confidence: 99%

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Large Mesopore Generation in an Amorphous Silica-Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Application to Catalytic Cracking

Ishihara¹,

Hashimoto²,

Nasu³

2012

Catalysts

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Tetraethoxy orthosilicate (TEOS) was used not only as a precursor of silica, but also as an agent which reinforces the skeleton of silica-gel to prepare an aerogel and resultant silica and silica-alumina with large pore size and pore volume. In this gel skeletal reinforcement, the strength of silica aerogel skeleton was enhanced by aging with TEOS/2-propanol mixed solution to prevent the shrink of the pores. When silica aerogel was reinforced by TEOS solution, the pore diameter and pore volume of calcined silica could be controlled by the amount of TEOS solution and reached 30 nm and 3.1 cm 3 /g. The results from N 2 adsorption measurement indicated that most of pores for this silica consisted of mesopores. Silica-alumina was prepared by the impregnation of an aluminum tri-sec-butoxide/2-butanol solution with obtained silica. Mixed catalysts were prepared by the combination of β-zeolite (26 wt%) and prepared silica-aluminas with large mesopore (58 wt%) and subsequently the effects of their pore sizes on the catalytic activity and the product selectivity were investigated in catalytic cracking of n-dodecane at 500 °C. The mixed catalysts exhibited not only comparable activity to that for single zeolite, but also unique selectivity where larger amounts of branched products were formed.

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Section: Catalytic Cracking Reactionmentioning

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Large Mesopore Generation in an Amorphous Silica-Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Application to Catalytic Cracking

Ishihara¹,

Hashimoto²,

Nasu³

2012

Catalysts

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“…Several studies reported on the influence of the aging conditions used during silica aerogel synthesis [36e59]. Many studies reported the strengthening of wet silica gels by means of an exchange into a silane precursor containing solution (TEOS or TMOS), a process more akin to a surface modification step, which prevents the cracking of silica aerogel during supercritical drying [39e42,44e47, 49,50,53,54]. Several studies have also reported on making the gels more rigid by aging them for extended periods of time (multiple days or even weeks) which helps in reducing the shrinkage of the final aerogels produced after supercritical drying [36,37,43,48,56].…”

Section: Introductionmentioning

confidence: 99%

Effect of aging on silica aerogel properties

Iswar

Malfait

Balog

et al. 2017

Microporous and Mesoporous Materials

129

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Silica aerogels' unique physical and chemical properties make them fascinating materials for a wide variety of applications. In addition to hydrophobization by silylation, aging is very important in the synthesis of silica aerogel by ambient pressure drying. Here we systematically study the effect of aging on the physico-chemical properties of silica aerogel with emphasis on ambient dried materials. Silica gels were aged for different times and at different temperatures in their gelation liquid (without solvent exchange), hydrophobized in hexamethyldisiloxane and subsequently dried either at ambient pressure or from supercritical CO 2 . Dynamic oscillatory rheological measurements demonstrate that aging reinforces the alcogels, particularly at high strain. The specific surface area decreases with increasing aging time and temperature as a consequence of Ostwald ripening processes during aging. With increasing aging time and temperature, the linear shrinkage and bulk density decrease and the pore size and pore volume increase for the ambient dried gels, but remain nearly constant for supercritically dried gels. Small-Angle X-ray scattering does not detect significant structural changes at length scales smaller than about hundred nanometers, but hints at systematic variations at larger length scales. The findings of this study highlight the importance of aging to increase the ability of the gel particle network to withstand irreversible pore collapse during ambient pressure drying.

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“…Transparent monolithic panes were developed in 1980-1990s (Airglass A.B) in Sweden, but advanced glazing systems with monolithic aerogel have still not penetrated the market (Duer and Svendsen 1998;Jensen et al 2004;Schultz and Jensen 2008). At the same time, granular translucent aerogels were manufactured, and, starting from 2005, many daylighting systems (polycarbonate panels, structural panels for continuous façades, insulated glasses) with translucent granular aerogel in interspace are available on the market (Rigacci et al 2004).…”

Section: Glazing Systemsmentioning

confidence: 99%

“…Aerogel is a highly porous nanostructured and light material, with a very low thermal conductivity (down to 0.010 W/m K). Granular translucent and transparent monolithic silica aerogels were developed as insulation materials for windows: advanced glazing systems with monolithic aerogel in the interspace are not yet used in mass production; nevertheless, many daylighting systems with translucent granular aerogels in interspace, such as polycarbonate panels, structural panels for continuous façades, and insulated glasses, are spreading on the market (Baetens et al 2011;Rigacci et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Nanogel Windows

Buratti

Moretti

2013

Nearly Zero Energy Building Refurbishment

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This chapter deals with the application of highly energy-efficient windows and skylights with silica nanogel as a strategy in the building refurbishment. Aerogel windows seem to have the largest potential for improving the thermal performance and daylight in fenestration industry, because of very low conductivity, density, and a good optical transparency. A state-of-the-art review of nanogel windows in building applications is firstly presented. Then, the proprieties of nanogel glazings in terms of thermal, lighting, and acoustic insulation solutions are discussed. Finally, the potential of the nanogel windows for energy saving in order to achieve a nearly zero-energy building is described, thanks to the results of a case study.

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Improvement of the silica aerogel strengthening process for scaling-up monolithic tile production

Cited by 39 publications

References 16 publications

Large Mesopore Generation in an Amorphous Silica-Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Application to Catalytic Cracking

Large Mesopore Generation in an Amorphous Silica-Alumina by Controlling the Pore Size with the Gel Skeletal Reinforcement and Its Application to Catalytic Cracking

Effect of aging on silica aerogel properties

Nanogel Windows

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