Preparation method of silicon dioxide aerogel

Abstract

The invention discloses a preparation method of silicon dioxide aerogel, and belongs to the technical field of a nano-porous material. The preparation method includes steps of performing hydrolytic polymerization on methyl trimethoxy silane to obtain a wet gel; staying the wet gel under a certain temperature and acquiring a contracted wet gel; sealing and aging the contracted wet gel through solvent; drying the aged wet gel and acquiring the aerogel. Through applying the methyl trimethoxy silane and the surface active agent to prepare the wet gel, the wet gel can bear heavy contraction and deformation; through staying, fluid in the wet gel hole is volatilized, and the wet gel is contracted; under the condition of low addition of the methyl trimethoxy silane, the aerogel with high density can be acquired; meanwhile, the aerogel grain has small dimension, the hole structure is more uniform, and the contact area between grains is bigger; thus the optical transparency and the mechanical performance of the aerogel are promoted.

Description

technical field [0001] The invention relates to a preparation method of silica airgel, which belongs to the technical field of nanoporous materials. Background technique [0002] As a typical nanoporous material, airgel is widely used in the fields of aerospace heat insulation, building energy-saving heat preservation, gas The fields of adsorption and filter materials, catalyst carrier materials and drug carrier materials have received extensive attention. However, due to the brittle network skeleton formed by orthosilicates, the mechanical properties of silica aerogels are poor, which severely limits their practical applications. [0003] Using methyltrimethoxysilane as a single precursor, Professor Kanamori of Kyoto University in Japan prepared an organic-inorganic hybrid silica airgel through a surfactant-water system. Due to the presence of methyl groups in the precursor, the airgel skeleton has a certain degree of flexibility, which significantly improves the mechanic...

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Problems solved by technology

However, as the concentration of the precursor increases, the viscosity of the solution system increases, and the diffusion of sol particles is restricted, resulting in larger airgel particles and uneven pore structure, which eventually leads to a decrease in its mechanical properties and a serious decrease in optical transparency. , especially when the prepared airgel density reaches 0.2g / cm 3 Above, the airgel is no longer transparent

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