Nano-pore SiO2 aerogel thermal insulation composite material and preparation method thereof

Abstract

The invention discloses a nano-pore SiO2 aerogel heat-insulating composite material and a preparation method thereof. The nano-pore aerogel heat-insulating composite material comprises SiO2 aerogel, an infrared opacifier and reinforced fibers. The preparation method comprises: mixing silicasol and indium-tin oxide ITO nano alcohol slurry or nano composite alcohol slurry of ITO and TiO2 through supersonic wave action, mixing the mixture and the reinforced fibers, directly pouring the mixture into a die to form a wet gel complex, and performing supercutical fluid drying. The material has good heat transfer function and good obstructing function on solid heat conduction, air heat convection and infrared radiation heat conduction, simultaneously has good hydrophobicity, simple technique, low cost and wide application scope, has the mechanical strength reaching more than 1.2 MPa, and can be used in situations with higher heat protection requirement in the fields of avigation, spaceflight, military affairs and domestic use.

Description

technical field [0001] The invention belongs to the field of high-efficiency thermal insulation materials, in particular to a nanoporous 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...

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