Method for quickly preparing hydrophobic silicon dioxide aerogel at low cost

A technology of hydrophobic silica and aerogel, applied in the direction of silica, silica, chemical instruments and methods, etc., can solve the problems of increasing preparation cost and time, achieve shortening preparation time, good thermal insulation, cost reduction effect

Inactive Publication Date: 2017-05-31
ECONANO TECH LTD BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the surface modification step can be omitted by the siloxane process with hydrophobic groups, a large amount of solvent exchange is required to replace the water in the wet gel to avoid drying shrinkage during atmospheric drying, which greatly increases the preparation cost and time.

Method used

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  • Method for quickly preparing hydrophobic silicon dioxide aerogel at low cost
  • Method for quickly preparing hydrophobic silicon dioxide aerogel at low cost
  • Method for quickly preparing hydrophobic silicon dioxide aerogel at low cost

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] A method for quickly preparing hydrophobic silica airgel at low cost, comprising the steps of:

[0041] S1. Mix the silicon source, water and surfactant to obtain a precursor solution; add an acid catalyst to the precursor solution, adjust the pH=3.5, and then hydrolyze to obtain a sol;

[0042]S2. Add an alkali catalyst dropwise to the sol obtained in S1, stir continuously during the dropwise addition, adjust the pH to 6.5, let the gel stand, age, and dry under normal pressure to obtain a hydrophobic silica airgel.

Embodiment 2

[0044] A method for quickly preparing hydrophobic silica airgel at low cost, comprising the steps of:

[0045] S1, methyltrimethoxysilane, water and DuPont Mix well to obtain a precursor solution; add an aqueous hydrochloric acid solution with a concentration of 0.1mol / L to the precursor solution, adjust the pH=3, then adjust the temperature to 45°C, and hydrolyze for 0.5h to obtain a sol, wherein methyltrimethoxysilane and The volume ratio of water is 1:4, DuPont and precursor solution volume ratio is 0.5:100;

[0046] S2. Add dropwise an ammonia solution with a concentration of 0.5 mol / L to the sol obtained in S1. Stir continuously during the dropwise addition, adjust the pH to 6.5, let the gel stand for 10 minutes, heat up to 45°C, age for 2 hours, and heat up to 60°C , dried for 2 hours, then heated to 120°C, dried for 2 hours, then heated to 150°C, dried for 4 hours to obtain a hydrophobic silica airgel.

[0047] The hydrophobic silica airgel that embodiment 2 is mad...

Embodiment 3

[0051] A method for quickly preparing hydrophobic silica airgel at low cost, comprising the steps of:

[0052] S1, the silicon source, water and DuPont Mix well to obtain a precursor solution; add an aqueous hydrochloric acid solution with a concentration of 0.1mol / L to the precursor solution, adjust the pH=3, then adjust the temperature to 45°C, and hydrolyze for 0.5h to obtain a sol, wherein the volume ratio of the silicon source to water is 1:3, the silicon source is a mixture of methyltrimethoxysilane and ethyl orthosilicate, in which the molar content of methyltrimethoxysilane is 60%, DuPont and precursor solution volume ratio is 0.5:100;

[0053] S2. Add dropwise an ammonia solution with a concentration of 0.5 mol / L to the sol obtained in S1. During the dropwise addition, keep stirring to adjust the pH to 6.5, let the gel stand for 5 minutes, heat up to 45°C, age for 2 hours, and heat up to 60°C. , dried for 2 hours, then heated to 120°C, dried for 2 hours, then heat...

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Abstract

The invention discloses a method for quickly preparing hydrophobic silicon dioxide aerogel at low cost. The method comprises the following steps of (S1) mixing a silicon source, water and a surfactant evenly to obtain a precursor solution, adding an acid catalyst to the precursor solution, adjusting the pH value to be 3-4, and then hydrolyzing to obtain sol; and (S2) dropwise adding an alkali catalyst to the sol obtained in the step (S1), continuously stirring in the dropwise adding process, adjusting the pH value to be 6-7, and carrying out gel standing, ageing and ambient pressure drying to obtain the hydrophobic silicon dioxide aerogel. The method is low in cost, free of solvent exchange, short in production cycle and free of environmental pollution; and the prepared hydrophobic silicon dioxide aerogel has good heat preservation and heat insulation properties, hydrophobicity and flexibility.

Description

technical field [0001] The invention relates to the technical field of silica airgel, in particular to a method for rapidly preparing hydrophobic silica airgel at low cost. Background technique [0002] Silica airgel is a lightweight nanoporous material with high porosity, large specific surface area, low density and low thermal conductivity. These characteristics make silica airgel materials useful in thermal, acoustic, optical, microelectronics , particle detection has very broad application potential. At present, the main problem of silica airgel is that the preparation cost is too high. Traditionally, the preparation of silica airgel needs to adopt supercritical drying process. However, supercritical drying requires the use of autoclave, and the process is complicated. High, and there is a certain degree of danger, so the atmospheric pressure drying process has gradually become the focus of everyone's attention. [0003] As early as the 1990s, Deshpande and Douglas of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/16B82Y40/00
CPCC01B33/16C01B33/163C01B33/166C01P2004/03C01P2004/61C01P2006/10C01P2006/32
Inventor 龚伦伦刘忠
Owner ECONANO TECH LTD BEIJING
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