How does the thermal conductivity of silica aerogel compare to that of traditional insulators?5 answersSilica aerogels exhibit remarkably low thermal conductivity, making them superior to traditional insulators. The thermal conductivity of silica aerogels is reported to be as low as 0.035 W/m·K, showcasing their excellent thermal insulation performance. Additionally, modifications in the microstructures and surface compositions of silica aerogels can further enhance their thermal management capabilities, allowing for on-demand thermal insulation, passive heating, or passive cooling. Furthermore, the incorporation of SiC nanowhiskers in aerogel composites has shown potential in reducing thermal conductivity even at high temperatures, with a value of 0.040 W/(m·K) at 500℃. These findings highlight the superior thermal conductivity properties of silica aerogels compared to traditional insulators, positioning them as efficient materials for thermal management applications.
How does the drying stage of silica aerogels effect the thermal insulation?5 answersThe drying stage significantly impacts the thermal insulation properties of silica aerogels. Different drying methods yield distinct characteristics. Freeze-dried cryogels and ambient-pressure-dried aerogels exhibit low thermal conductivities, high porosities, and specific surface areas, making them ideal for thermal insulation applications. Additionally, the use of glass fibers felt with SiC nanowhiskers in aerogel composites enhances mechanical strength and reduces heat transfer by radiation, resulting in improved thermal insulation performance at high temperatures. Moreover, the incorporation of chitosan in silica aerogels enhances their thermal stability, hydrophobicity, and adsorption properties, making them promising for both insulation and adsorption applications. These findings underscore the importance of the drying stage in tailoring the thermal insulation capabilities of silica aerogels for various practical applications.
What are the current trends in the use of aerogels in industrial applications?4 answersCurrent trends in the industrial application of aerogels indicate a growing interest in various sectors. Silica aerogels, known for their exceptional properties, are primarily utilized in thermal insulation, with emerging applications in electric vehicles and building insulation. Additionally, aerogels made from biopolymers like nanocellulose are gaining attention in bone tissue engineering, offering mimicry of the extracellular matrix and drug delivery capabilities for tissue healing and growth. Furthermore, the use of aerogels in construction for energy-saving purposes is on the rise, with applications in building insulation through aerogel glass, mortar, felt, and coatings being prominent. The versatility of aerogels, spanning from thermal insulation to biomedical applications, showcases a promising future for their industrial utilization.
What is the importance of porosity in aerogels?5 answersPorosity is of great importance in aerogels as it directly affects their performance and properties. High porosity allows for low density, low thermal conductivity, and high surface area, making aerogels lightweight and efficient in applications such as insulation and sound mitigation. However, achieving high porosity while maintaining desirable mechanical strength can be challenging. Different methods have been explored to control and optimize porosity in aerogels. For example, using preformed colloids can help reduce pore size while maintaining high porosity. The surface porosity of graphene-based aerogels can be controlled through regulation of crosslinking agents and shear stress during fabrication. Additionally, top-down approaches, such as delignification of wood substrates, have been used to generate aerogels with high porosity and diverse surface chemistry. Overall, understanding and controlling porosity in aerogels is crucial for tailoring their properties and optimizing their performance in various applications.
What is the best way to make an aerogel blanket?4 answersThe best way to make an aerogel blanket is by impregnating a catalyzed sol into a blanket substrate and allowing it to remain in the impregnation tank for a specific time to control flowability and achieve a viscosity that enables easy injection into the blanket. This method ensures uniform formation of aerogel inside the blanket, improving the uniformity of pore structure and insulation performance. It also reduces the loss of raw material, minimizes processing problems, and decreases dust generation. Another approach involves using a bobbin on which the blanket is wound, a gelation tank, a drive member to rotate the bobbin, and a silica sol supply member to inject silica sol into the gelation tank and impregnate it into the blanket. This method simplifies manufacturing equipment, improves efficiency, and enhances thermal conductivity by uniformly forming aerogel in the blanket substrate.
Who makes graphene Aerogel?10 answers