Silica-based porous bulk for heat insulating material and coating-dry pressing preparation method thereof

A technology of silica and thermal insulation materials, which is applied in heat exchange materials, chemical instruments and methods, and other chemical processes, etc., can solve problems such as poor hydrothermal stability of aerogels, and achieve widened application fields and simple operation process. , the effect of simple equipment

Inactive Publication Date: 2011-02-16
BEIHANG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Second, MCF-phase SiO 2 After hydrothermal treatment in the powder preparation process, the polycondensation between Si-OH is complete, and SiO 2 The wall is strong and dense, resulting in MCF phase SiO 2 The powder has strong hydrothermal stability, while SiO 2 Airgel has poor hydrothermal stability and needs to be modified before it can be used in a high temperature environment containing water vapor

Method used

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  • Silica-based porous bulk for heat insulating material and coating-dry pressing preparation method thereof
  • Silica-based porous bulk for heat insulating material and coating-dry pressing preparation method thereof
  • Silica-based porous bulk for heat insulating material and coating-dry pressing preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0052] Example 1: Surface coated with Al 2 o 3 silica-based porous blocks

[0053] Step 1. Preparation of porous silica powder

[0054] (A) In a water bath at 38°C, the nonionic surfactant P123 (EO 30 PO 70 EO 30 ) was dissolved in hydrochloric acid (HCl) with a molar concentration of 1.6 mol / L, and stirred at a speed of 900 rpm for 60 minutes to form solution A;

[0055] (B) In a water bath at 38°C, add trimethylbenzene (TMB) to solution A to form solution B;

[0056] (C) In a water bath at 38°C, add tetraethyl orthosilicate (TEOS) to solution B, and stir at a speed of 900 rpm for 20 hours to form suspension A;

[0057] (D) After transferring the suspension A to a hydrothermal kettle, place it in an oven, keep it warm at 140°C for 24 hours, then cool it down to 25°C naturally with the oven, take it out, and obtain the suspension B;

[0058] (E) Transfer the suspension B to a Buchner funnel, and filter under 0.01MPa vacuum for 20 minutes to obtain a white powder;

[...

Embodiment 2

[0077] Example 2: Surface coated TiO 2 silica-based porous blocks

[0078] Step 1. Preparation of porous silica powder

[0079] (A) In a water bath at 40°C, the nonionic surfactant P123 (EO 30 PO 70 EO 30 ) was dissolved in hydrochloric acid (HCl) with a molar concentration of 1.6 mol / L, and stirred at a speed of 500 rpm for 120 minutes to form solution A;

[0080] (B) in a water bath at 40°C, add trimethylbenzene (TMB) to solution A to form solution B;

[0081] (C) In a water bath at 40°C, add tetraethyl orthosilicate (TEOS) to solution B, and stir at a speed of 500 rpm for 30 hours to form suspension A;

[0082] (D) After transferring the suspension A to a hydrothermal kettle, place it in an oven, keep it warm at a temperature of 90°C for 90 hours, then cool it down to 35°C naturally with the oven, take it out, and obtain a suspension B;

[0083] (E) Transfer the suspension B to a Buchner funnel, and filter under vacuum at 0.005MPa for 10 minutes to obtain a white powd...

Embodiment 3

[0097] Example 3: Surface coated with Al 2 o 3 silica-based porous blocks

[0098] Step 1. Preparation of porous silica powder

[0099] (A) In a water bath at 36°C, the nonionic surfactant P123 (EO 30 PO 70 EO 30 ) was dissolved in hydrochloric acid (HCl) with a molar concentration of 1.6 mol / L, and stirred at a speed of 750 rpm for 100 minutes to form solution A;

[0100] (B) In a water bath at 36°C, add trimethylbenzene (TMB) to solution A to form solution B;

[0101] (C) Add tetraethyl orthosilicate (TEOS) to solution B in a water bath at 36°C, and stir at a speed of 750 rpm for 24 hours to form suspension A;

[0102] (D) After transferring the suspension A to a hydrothermal kettle, place it in an oven, keep it at a temperature of 120°C for 48 hours, then cool it down to 30°C naturally with the oven, take it out, and obtain a suspension B;

[0103] (E) Transfer the suspension B to a Buchner funnel, and filter it under a vacuum condition of 0.02MPa for 30 minutes to...

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Abstract

The invention discloses a silica-based porous bulk for heat insulating material and a coating-dry pressing preparation method thereof. The preparation method comprises the following steps of: preparing porous silica powder through the hydrolytie polycondensation of tetraethoxysilane by using tetraethoxysilane as a precursor, a nonionic surfactant P123 as a template agent and trimethylbenzene as aswelling agent; hydro-thermally treating the silica powder so as to ensure that Si-OH in pore walls is completely polycondensed; coating the hydro-thermally treated silica powder with sol, and preparing the silica-based porous bulk for a heat insulating material by using the dry pressing method. The silica-based porous bulk is obtained by sintering the porous silica powder with oxide coated surface, wherein the oxide is alumina or titania. The mesoporous aperture of the silica-based porous bulk prepared by using the method is 21-35 nm, the mesoporous window is 10-18 nm, the total porosity is 65-82%, the mesoporosity is 80-99%, and the tensile strength is 45-180 MPa.

Description

technical field [0001] The invention relates to a thermal insulation material, more particularly, to a silica-based porous block material for thermal insulation materials and a preparation method thereof. Background technique [0002] Since Mobil synthesized MCM-41 in 1992, ordered mesoporous powder materials using surfactants as templates have been widely used in catalysis, separation, Biosensors and drug delivery have shown broad application prospects. [0003] SiO 2 Airgel and its composite materials have been put into use in recent years as a kind of high nanoporous thermal insulation material due to its extremely low thermal conductivity. SiO 2 The porosity of the airgel is in the range of 80% to 99.8%, and the thermal conductivity can be less than the thermal conductivity of air without convection, 0.023W / m·K, and between 0.01 and 0.03W / m·K. But SiO 2 Aerogels have low mechanical strength due to their extremely low bulk density and disordered pore distribution. In...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K3/00C09K5/14
Inventor 谷景华张丽杰张跃
Owner BEIHANG UNIV
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