Preparation method of hydrophobic foamed cement composite silicon aerogel material

Abstract

The invention belongs to the technical field of preparation of nano porous materials, and particularly relates to a preparation method of a hydrophobic foamed cement composite silicon aerogel material. Tetraethyl orthosilicate is taken as a precursor, organosilane is taken as a modifying agent, foamed cement is taken as a hard reinforcing matrix, a sol-gel method, an in-situ polymerization methodand a vacuum impregnation process are adopted, and rapid ethanol supercritical drying is combined to prepare the composite silicon aerogel material. The prepared hydrophobic foamed cement composite silicon aerogel material has a density of 0.40-0.73 g / cm<3>, the compressive strength is 0.8-2.1 MPa, the normal-temperature thermal conductivity is 0.054-0.186 W*m<-1>*K<-1>, and the hydrophobic angleis 118-146 degrees. The process is cheap in material and simple and convenient in preparation method; the production period is compressed from 5-7 days of a conventional method to within 10 hours; a large amount of ethanol is saved while the preparation period is shortened; and the preparation method has the significance of large-scale industrial production.

Description

technical field [0001] The invention belongs to the field of preparation technology of nanoporous materials, and relates to a preparation method of a hydrophobic foamed cement composite silica airgel material with high temperature resistance, low thermal conductivity, good hydrophobicity and high strength. Background technique [0002] SiO 2 Airgel is a solid material with a nanoporous network structure. As the material with the best thermal insulation performance so far, SiO 2 Airgel has excellent properties such as high specific surface area, high porosity, low density and low thermal conductivity, and has broad application prospects as thermal insulation and thermal insulation materials in aerospace, construction, chemical and other fields. However, silica airgel is brittle and has low strength, which restricts its engineering application as a thermal insulation material in many fields. Moreover, SiO prepared by conventional methods 2 The surface of airgel contains a ...

AI Technical Summary

Problems solved by technology

However, silica airgel is brittle and has low strength, which restricts its engineering application as a thermal insulation material in many fields.

Moreover, SiO prepared by conventional methods 2 The surface of airgel contains a certain amount of hydrophilic group silanol. When used in a high temperature and humid environment, it is easy to absorb moisture and cause the shrinkage of the pore structure and the collapse of the skeleton, resulting in a decrease in its heat insulation effect and a shortened service life.

[0003] At present, glass fiber is widely used in the industrialization of airgel as a low-cost reinforcement phase, but its soft and flexible characteristics cannot withstand shear stress, so it is not suitable for direct use as a load-bearing structure

Moreover, in humid environments, the performance of airgel components is reduced

[0004] Foamed cement is used in the field of building insulation due to its low cost and light weight, but its relatively high thermal conductivity and low operating temperature prevent it from being used in high-temperature thermal equipment

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