Preparation and Characteristic of the Novel Multiple-Layer Thermal Insulation Nanocomposite Materials

Abstract

Thermal insulation nanomaterials based on aerogels have attracted more and more researchers' attention due to their low thermal conductivity and lightweight characteristics. However, the high-temperature thermal insulation performance and the mechanical strength of the material itself remain a great challenge. We developed a method to construct multiscale structures of thermal insulation materials based on dry aerogel particles, ultralong nanowires, and interfacial crosslinkers. In our work, the introduction of surfactants enabled the effective dispersion of aerogels and nanowires in the aqueous solution instead of in an organic solvent. Also, thanks to the synergistic effect of crosslinkers and nanowires, the materials exhibit a good mechanical strength; the maximum value of tensile strength for nanocomposite materials is up to 0.76 MPa. Aerogels with a resistance of 1000 °C and reflecting screens were adopted to prepare the multiple-layer thermal insulation materials, enabling the obtained material to show the outstanding thermal insulation property [0.028 W (m•K) −1 at 25 °C and 0.059 W (m•K) −1 at 800 °C]; additionally, when the temperature of the heating surface was raised to 800 °C, the back surface temperature of 15 mm materials increased to an ultimate temperature of only 218 °C after heat treatment for 500 s. These favorable multi-features indicate the materials are ideal for thermal insulation in industrial, aerospace, and even extreme environmental conditions.

A Review of Novel Heat Transfer Materials and Fluids for Aerospace Applications

“…For Reynolds numbers superior to 2300, the Reynolds number, the liquid Froude number, and the Morton number should be considered. The Froude number, Fr, based on the liquid superficial velocity, can be expressed by Equation (10):…”

“…Conversely, it may also be desirable to employ materials with enhanced insulation capabilities to prevent substantial amounts of heat generated by hypersonic vehicles or atmospheric re-entry from reaching undesirable sections of the aircraft. Additionally, such materials can be utilized to prevent the loss of heat within survival cells [9,10]. Frequently, particularly in insulating materials, the objective is to elevate the onset temperature of material degradation, aiming to enhance safety and enable superior vehicle performance [10].…”

“…Additionally, such materials can be utilized to prevent the loss of heat within survival cells [9,10]. Frequently, particularly in insulating materials, the objective is to elevate the onset temperature of material degradation, aiming to enhance safety and enable superior vehicle performance [10]. Here are some recent innovations for the utilization of these materials in the aerospace industry, particularly in polymer matrix composites and aerogels, which have been extensively explored in recent studies.…”

“…Kong et al [10] employed surfactants to disperse dry aerogel particles and hydroxyapatite (HAP) nanowires in an aqueous solution, yielding aerogels that, combined with reflective screens, formed a multilayered material capable of withstanding temperatures up to 1000 • C. The resulting material exhibited excellent insulation properties, with a thermal conductivity of 0.028 W/(m•K) at room temperature and 0.059 W/(m•K) at 800 • C [10].…”

“…In the case of heat generated by combustion, the opposite effect may be desired, where it is essential to prevent the heat from spreading throughout the entire spacecraft and concentrate it in a zone more resistant to heat. In this scenario, nanoparticles can contribute to reduce the thermal conductivity of the material, allowing the material to withstand higher temperatures without degradation and preventing the spread of potential flames [10,11].…”