Quick preparation method of water glass based fiber reinforced SiO2 aerogel block

Abstract

The invention relates to a quick preparation method of a water glass based fiber reinforced SiO2 aerogel block. The quick preparation method includes: using industrial-grade water glass as a silicon source, and forming fiber reinforced SiO2 wet gel through sol-gel reaction; performing one-step solvent replacement and surface group modification through mixed liquid of an organic solvent/modifier, and drying at normal pressure to obtain a SiO2 composite aerogel block. Fiber reinforced SiO2 aerogel has physical characteristics like large specific surface area (600-900m2/g), high pore capacity, high elasticity and super-hydrophobicity (hydrophobic angle range is 120-145 DEG C) and can present excellent mechanical and thermal performance along temperature change, so that application value of the material in the field of photoelectric devices, gas-sensitive sensors and heat insulation. The quick preparation method is simple in process path, high in operability, capable of quickly obtaining large-size uncracked SiO2 composite aerogel materials and conducive to promoting industrial production of aerogel.

Description

technical field [0001] The invention belongs to the technical field of preparation of airgel materials, and relates to water glass-based fiber-reinforced SiO 2 Rapid preparation method of airgel bulk. Background technique [0002] SiO 2 As a special nanoporous material, airgel has many excellent characteristics, such as: low density (~0.003g / cm 3 ), high surface area (500~1200m 2 / g), high porosity (80~99.8%), low dielectric constant (k=1.0-2.0), low refractive index (~1.05) and extremely low thermal conductivity (0.005W / (mK)), etc. Due to the above properties of itself, SiO 2 Aerogels have been successfully used in detectors, acoustic impedance coupling materials, catalysts and carriers, high-efficiency heat insulation materials, and the preparation of high-efficiency rechargeable batteries. However, pure SiO 2 The airgel network skeleton is very fragile, with low mechanical strength and poor toughness, which limit its application in the field of thermal insulation. ...

AI Technical Summary

Problems solved by technology

However, pure SiO 2 The airgel network skeleton is very fragile, with low mechanical strength and poor toughness, which limits its application in the field of thermal insulation

[0003] The supercritical drying method also has many disadvantages in the preparation process, such as: high risk, high energy consumption, complex equipment, and difficulty in achieving large-scale continuous production

Some scholars have tried to use organic silicon sources such as tetraethyl orthosilicate (TEOS) to obtain SiO by atmospheric pressure drying at room temperature. 2 Airgel, although the product has excellent performance, but the organic silicon source is expensive and toxic, the cost is high and pollutes the environment, it is difficult to promote the industrial production and application of airgel

At the same time, the problems of long solvent replacement cycle, cumbersome surface modification process, and large solvent consumption in the normal pressure drying process have not been completely solved. If the airgel is to be widely used, it is necessary to reduce the production cost and simplify the preparation process.

In addition, SiO prepared from tetraethyl orthosilicate 2 The high content of silicon-oxygen covalent bonds in airgel, poor agglomeration and brittleness will also limit its application in many aspects, such as: load-bearing applications when the external load exceeds the fracture stress

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