Preparation method of nanowire/silicon-aluminum aerogel composite material

Abstract

The invention discloses a preparation method of a silicon dioxide nanowire-reinforced silicon-aluminum aerogel composite material. According to the invention, silicon-aluminum aerogel prepared by using aluminum chloride hexahydrate and tetraethoxysilane as co-precursors and using water and ethanol as solvents is used as a matrix, silicon dioxide nanowires are used as a reinforcing agent, and compounding and supercritical drying processes are conducted to prepare the silicon dioxide nanowire / silicon-aluminum aerogel composite material with excellent performance . The obtained aerogel compositematerial is low in sample density, high in specific surface area, high in mechanical property and good in high-temperature resistance. The preparation method is simple in process, flexible to operateand easy for mass production.

Description

technical field [0001] The invention belongs to the technical field of preparation of inorganic nanoporous materials, and in particular relates to a preparation method of a silica nanowire / silicon aluminum airgel composite material. Background technique [0002] Airgel is a nano-porous solid material with a three-dimensional network structure based on nanoparticles or polymer molecules. Its unique structure makes it have excellent characteristics such as low density, high porosity, high specific surface area, and low thermal conductivity. , has great application prospects in aerospace, construction, energy, information, catalysis, environmental protection and other fields. [0003] In terms of composition, aerogels are mainly divided into inorganic aerogels, organic aerogels and carbon aerogels. At present, the research on inorganic aerogels is the most extensive, such as SiO 2 Aerogel, Al 2 o 3 Aerogel, ZrO 2 Airgel and Al 2 o 3 -SiO 2 Binary composite airgel, etc.; ...

AI Technical Summary

Problems solved by technology

[0003] In terms of composition, aerogels are mainly divided into inorganic aerogels, organic aerogels and carbon aerogels. At present, the research on inorganic aerogels is the most extensive, such as SiO 2 Aerogel, Al 2 o 3 Aerogel, ZrO 2 Airgel and Al 2 o 3 -SiO 2 Binary composite airgel, etc.; Al 2 o 3 -SiO 2 The airgel not only improves the Al 2 o 3 The high temperature stability of airgel can make up for SiO 2 Airgel has the disadvantage of low temperature; now someone has studied a kind of pseudo-boehmite and tetraethyl orthosilicate as precursors, through sol-gel, drying, calcination and other processes to prepare Al 2 o 3 -SiO 2 The method of composite airgel, the present invention has the advantages of safe operation, low energy consumption, cheap raw materials, etc., but the process is more complicated; the same as silica airgel, due to the nanoporous network structure characteristics, there are The problems of poor mechanical properties and easy collapse of the structure greatly limit its application in related fields; at present, adding reinforcements to enhance aerogels is the main method to improve the mechanical properties of aerogels, and the main reinforcements are mullite Fiber, glass fiber, carbon fiber, etc., Chinese patent CN201810530541.3 uses airgel as the matrix and fiber as the reinforcement, and uses a mixture of silica sol, modified solution and alkaline solution as the impregnation treatment reagent to prepare a fiber-reinforced airgel Adhesive composite materials, the process is simple, easy to operate, and is conducive to large-scale production; however, most fibers cannot be well combined with the airgel matrix due to the problem of surface tension, which makes the prepared airgel composite materials easy to appear. Severe slag falling and high temperature curling; some micron-scale fiber reinforcements can not only improve the mechanical properties of airgel, but also cause a significant decrease in the specific surface area of ​​the airgel composite material, and a significant increase in thermal conductivity. Limits the application range and service life of fiber / aerogel composites

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