A review on silica aerogel-based materials for acoustic applications

Acoustical Properties of Fiberglass Blankets Impregnated with Silica Aerogel

“…For the filling ratios of 75% and above the characteristic impedance (see Figure 9) and attenuation of sound in a layer with such small pores becomes very high, limiting the value of the absorption coefficient [27]. The absorption coefficient of this relatively thin fibrous blanket with 50-75% filling ratios is still relatively high (30-70%) particularly above 1000 Hz (see references [4,13]). This level of absorption has a practical value in applications related to engineering noise control.…”

“…Aerogel blankets consist of a silica aerogel embedded in a reinforcing fibrous matrix, which allows the brittle aerogel to become a flexible, durable solid used for buildings [3] and pipelines. The silica aerogel can undergo a surface modification process (typically hydrophobization) to enhance surface life stability [4], thus reducing the aerogel's susceptibility to moisture and rapid spoilage [5]. Silica aerogels themselves have porosity values as high as 98%, densities as low as 0.05-0.5 g/cm 3 , surface areas in the range of 300-1000 m 2 /g [6] and thermal conductivity values as low as 0.02 W/mK [7].…”

“…They found that neat UPVC only had a maximum sound absorption of 17% at a frequency of 1800 Hz; however, when silica aerogel was applied at 0.5, 1.5 and 3 weight %, the maximum sound absorption of UPVC increased to 24, 28 and 43%, respectively, therefore highlighting that acoustical properties were greatly increased upon the addition of silica aerogel. A more extensive review of acoustical properties of aerogels can be found in reference [4].…”

Recent Progresses in Eco-Friendly Fabrication and Applications of Sustainable Aerogels from Various Waste Materials

“…Many novel applications of aerogels besides thermal insulation have been discovered such as personal care products, medical devices, oil and organic solvents sorption, filtration, sound insulation, energy absorption, energy storage, bioelectronics, water treatment and catalyst, offering sustainable solutions for environmental and energy problems. Previous reviews mainly focused on a specific types of aerogel such as silica aerogel [16], cellulose aerogel [17], and carbon aerogel, [18] or on certain application such as acoustic insulation [19], photocatalyst [20] and biomedical applications [21]. However, taking advantage of wastes such as municipal solids, agricultural and industrial by-products to create high-value engineering aerogels has been a general trend in the world.…”

Curcumin-loaded metal oxide aerogels: supercritical drying and stability

“…15 To the interesting porosity of the aerogels are added their molecular homogeneity 16 and the possibility of their preparation in bulk. Although these materials were reported for the rst time in 1931 by S. S. Kistler, 17 their broad range of technological applications increased noticeably in the last decades with potential uses for thermal 18 and acoustic insulation, 19 photoluminescence 20 and radioluminescence devices, 21 as adsorbents, 8,[22][23][24][25] catalysts, 12,26 and catalyst supports. [27][28][29][30] Furthermore, hybrid organic-inorganic aerogels were found to be promising materials as optical components, 31,32 insulating materials in microelectronics, 33 host materials for sensors, 34 and for drug delivery.…”