American Chemical Society
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Development of Mechanically Strong Ambient Pressure Dried Silica Aerogels with Optimized Properties

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journal contribution
posted on 2015-04-09, 00:00 authored by Hajar Maleki, Luisa Durães, António Portugal
Ambient pressure dried (APD) silica aerogel-like monoliths with different underlying silica structures have been developed through a simple wet chemical approach. The improvement of the mechanical properties was accomplished by cross-linking the silica surface with triacrylate cross-linker. A solvent exchange carried out by soaking the gels in a low surface tension solvent allowed to avoid the nonsafe and costly supercritical drying process. In this context, two different sets of aerogel-like monoliths have been produced, and their main properties, namely, bulk density, mechanical strength, and thermal conductivity, were studied and modeled using the statistical Central Composite Design (CCD) approach. The empirical models derived for each property of the aerogel-like monoliths lead to further evaluation of the desirability function and optimization of silica aerogel-like properties. The key properties of the optimized APD monoliths were compared with the supercritical dried aerogels with the same synthesis conditions. Finally, the suitability of optimized silica aerogel-like and aerogel monoliths for intended space applications were further investigated by conducting several standard tests. The improved properties of the obtained APD aerogel-like monoliths render them attractive for high-technology applications, and, due to the low energy consumption of the synthesis process, they are competitive with their supercritically dried (SCD) counterparts, by presenting a best value-for-money compromise.