Nano-hole aerogel heat-insulating composite material and preparation method thereof

Abstract

The invention discloses a nano-hole aerogel heat-insulating composite material and a preparation method thereof. The nano-hole aerogel heat-insulating composite material comprises SiO2 aerogel, ITO nano powder material or nano compound powder material of ITO and TiO2, and reinforced fiber felt or prefabricated body. Through action of ultrasonic wave, silicon gel and ITO nano alcohol slurry or nano compound alcohol slurry of ITO and TiO2 are mixed and then flow into the fiber felt or the prefabricated body through infiltration technology to form wet gel compound to be subjected to supercritical fluid drying. The material has good heat transfer and obstruction functions for solid heat transfer, air heat convection and far infrared radiation heat transfer, has good hydrophobic property at the same time, and has simple process and low cost; the mechanical strength can reach 0.10 to 2MP; and the material has wide application range, and can meet higher requirement of heat protection in navigation, spaceflight, military affairs and civilian use.

Description

technical field [0001] The invention belongs to the field of high-efficiency thermal insulation materials, in particular to a SiO 2 Airgel thermal insulation composite material and preparation method thereof. Background technique [0002] SiO 2 Airgel has the characteristics of high specific surface area, ultra-low density and nanoporous network structure, the porosity is as high as 98.9%, the pore size is generally in the mesopore range, and the specific surface area is as high as 1000m 2 / g, the density is 3~600kg / m 3 adjustable within the range. The structural specificity of airgel makes its refractive index, acoustic impedance and thermal conductivity low, and its adsorption performance is excellent. application prospects. [0003] SiO 2 Airgel is considered to be the solid material with the best thermal insulation performance at present, but the inherent low strength of airgel materials, high brittleness, difficulty in forming and high cost restrict its promotion ...

AI Technical Summary

Problems solved by technology

When the binder is added, although the strength of the composite material can be improved to a certain extent, the high-efficiency thermal insulation properties of the airgel material are also lost at the same time; Adding agent (titanium dioxide) to form a gel and then drying the material by supercritical fluid (see Chinese patent 97106652.3 "Modified nano-insulation material and its production process"), the infrared opacifier is difficult to disperse evenly, and the mechanical strength is limited. Difficult to meet the use requirements of harsh environments; ③Using fiber as a reinforcing phase, adopting sol-gel process and supercritical fluid drying process to form airgel composite materials (see US Patent US6068882 and Chinese Patent 200510031952.0 "An Airgel Thermal Insulation Composite material and its preparation method"), the material has good thermal insulation effect and performance, but the US patent US6068882 reduces the infrared transmittance by depositing molecular carbon or metal on the surface of the fiber, and the process is more complicated, while China Patent 200510031952.0 is to prepare SiO by in-situ composite method 2 / TiO 2 Introduction of TiO after composite gel 2 The use of airgel to reduce the infrared transmittance, although the process is simpler than the former, but due to the formation of TiO 2 It is mostly amorphous, and its effect on reducing infrared transmission is limited

In addition, the material made of US Patent US6068882 has poor hydrophobicity, and the heat insulation effect will be reduced due to water absorption during actual use