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, sub‐critical 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.