Synthesis of silica aerogel thin sheets and evaluation of its thermal, electrical, and mechanical properties

Abstract

Silica aerogels are excellent thermal and acoustic insulators because of interconnected open nanopores with more than 90% porosity and higher surface area. Silica aerogel is derived by sol-gel process and dried under super-critical, subcritical or ambient pressure conditions. Thin silica aerogel sheets could be effective thermal insulators but high fragility hinders the wider applications. We have successfully developed a synthesis method for thin, flexible, and non-fragile aerogel sheets with excellent hydrophobicity, lower thermal conductivity, and non-combustible properties via ambient drying method. The silica aerogel sheets prepared compose of silica aerogel powder, fiber glass chopped strands, and solvent-based binder. Aerogel thin insulation sheets of thickness 164 μm were prepared by pressing through rollers using aerogel paste composed of aerogel powder, fiber glass strands, and binders. The thermal conductivity values obtained were between 0.02~0.63 W/mK at temperature 25~400°C, contact angle θ = 121' , weight loss 3.91% when heated up to 800°C in air, dielectric voltage breakdown 3.67 kV, dielectric strength 6.37 kV/mm and tensile strength of 2.65 N/mm². The overall thermal, electrical, and mechanical evaluation of aerogel thin insulation sheet showed they have higher potential to replace existing thick and bulky aerogel composites as thermal and electrical insulators in aviation, automobiles, electronics, and high power batteries.

Active thermography characterization of aerogel materials for vehicle electrification

“…An example of thermal characterization of aerogel materials may be found in [16] [17] [18], basing on the Laser Flash technique that is useful to provide thermal diffusivity and conductivity values in a very fast way.…”

Hierarchical Cellulose Superinsulation Membrane

“…The superinsulation membrane shows structural robustness and resilience to organic degenerative tests, as highlighted in Figure 1b and S9, Supporting Information. As shown in Figure 1, [22][23][24][25][26][27][28][29] this flexible nanofibrils-based superinsulation membrane provides a promising alternative for a number of applications that require high standards of thermal management competencies, including thermal runaway mitigation and heat resistance under continuous solar radiation.…”

Preparation and Properties of Polyurethane Composite Foams with Silica-Based Fillers

“…Silica aerogel is an ideal porous material with a pearl necklace-like three-dimensional structure having interstitial mesopores. Such structural feature makes it possible to use it as an insulator because it shows low density and low thermal conductivity due to high porosity with 90% or more of air [23][24][25][26]. Silica aerogel as an insulating material has a thermal conductivity of 20 mW/mK or less, and has even smaller thermal conductivity than other conventional insulating materials.…”