Synthesis and Characterization of Flexible Silica Nanoporous Aerogel as High Efficient Thermal Insulator

Silica aerogel is a highly porous material with pore diameters in the range of 2–50 nm [1, 2]. The nanoporous structure of the silica aerogels having a high porosity above 90%, makes the aerogels a highly thermal insulating materials with a super-low thermal conductivity as low as 0.013 W.m-1.K-1 [3]. However, because of their nanoporous nature and high porosity, silica aerogels generally have poor mechanical stability (e.g., low strength and high brittleness). The low flexural and collapse strength of the aerogels greatly limit their applications for thermal insulation applications. Many researches are done to improve the mechanical properties of silica aerogels which among them introducing reinforced fibers into the silica aerogels and synthesizing the fiber-reinforced aerogels is one of the most effective methods for improving the mechanical properties of the aerogel [4]. In this study, we synthesized flexible silica aerogels with low density and thermal conductivity. Silica aerogel was synthesized from tetraethoxysilane (TEOS) using sol-gel method in the presence of fibers. The obtained alcohogel was dried via solvent exchange method at ambient pressure without using highly expensive supercritical drying method. Obtained aerogels have high degree of flexibility and low thermal conductivity (0.0.18 W.m-1.K-1). The porosity of synthesized aerogel was obtained around 89.5% which is a high porosity among aerogels. Also the thermal property of synthesized aerogel was studied by thermal gravimetry analysis (TGA).