Method for preparing potassium hexatitanate whisker composite SiO2 aerogel heat insulating material

Abstract

The invention discloses a method for preparing potassium hexatitanate whisker composite SiO2 aerogel thermal insulation material, which comprises the steps of adopting a potassium hexatitanate whisker as a reinforcing phase, utilizing a coupling agent for the surface modification of the potassium hexatitanate whisker, preparing a SiO2 gel precursor at the same time, mixing and stirring the modified potassium hexatitanate whisker and the SiO2 gel precursor, keeping stand to gelatinate, aging to obtain SiO2 gel containing the potassium hexatitanate whisker, then performing supercritical drying and heat treatment through a high pressure kettle, and obtaining the potassium hexatitanate whisker composite SiO2 aerogel thermal insulation material. The composite thermal insulation material has good barrier function on solid heat transfer and air convection heat transfer, can effectively block infrared radiation heat transfer at the same time, has heat conductivity coefficient of between 0.01 and 0.015w / m.k at normal temperature, and improves 3 to 5 times of strength than SiO2 aerogel. The method has wide application range, and can meet operating requirements of more harsh thermal protection conditions of aviation, spaceflight, military affairs and civil use.

Description

technical field [0001] The invention relates to a potassium hexatitanate whisker composite SiO 2 The invention discloses a preparation method of an airgel heat insulating material, which belongs to the technical field of heat insulating materials. Background technique [0002] Compared with traditional thermal insulation materials such as microporous calcium silicate, glass wool, rock wool, etc., SiO 2 Airgel belongs to the scope of nanotechnology. It is a lightweight nano-amorphous solid material with a porosity as high as 80% to 99.8%, and has good heat insulation performance. Although the thermal conductivity of traditional thermal insulation materials is low at room temperature, its thermal conductivity will increase with the increase of temperature at high temperature, which cannot meet the requirements of current industrial development and energy saving. SiO 2 The unique nanoporous structure of aerogel endows it with excellent thermal insulation properties, making i...

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Problems solved by technology

Chinese patent CN1214319A discloses a modified nano insulation material, which consists of SiO 2 TiO in a fine network formed by particle crosslinking 2 Composed of inorganic reinforcing agents, they have higher strength and lower thermal conductivity, but their thermal conductivity increases greatly at high temperatures, and their thermal conductivity at room temperature and 800K temperature are 0.021w / m·k respectively and 0.045w / m·k, and its mixed molding adopts conventional methods, so that the combination effect of each phase is not very ideal

Chinese patent CN1803602A discloses a kind of brucite fiber reinforced SiO 2 The preparation method of the airgel heat insulation material, the heat insulation material has good hydrophobicity, the density is low, the thermal conductivity performance is good, but it adds more components, such as chemical dispersants, inorganic sunscreens etc. Although the material performance has been improved, due to the difference in physical properties (such as surface tension, wettability, density, etc.) between the fiber (or whisker) and the airgel, the uniform dispersion of the fiber (or whisker) And strong bonding is often difficult to obtain, and the mutual attraction of electrostatically charged surfaces can also cause fibers (or whiskers) to gather into balls or form parallel bundles, forming uneven clumps in the final product, thereby affecting mutual The combination effect between the phases, and because there is no special treatment, the combination between the phases is not ideal

Chinese patent CN1636917A discloses a method for preparing a calcium silicate composite nanoporous super-insulation material. The composite of this material adopts vacuum impregnation technology, which has certain benefits for the combination of phases, which makes its strength increase by as much as SiO 2 The strength of airgel itself is 3 to 4 times, but its thermal conductivity is still on the high side. The thermal conductivity at room temperature and 500°C are 0.019w / m·k and 0.038w / m·k respectively. Difficulty working to achieve desired results

[0004] The preparation of SiO published above 2 The method of airgel composite material is strengthened and toughened, although it has mechanical properties applied in engineering, it affects the thermal conductivity of the material or the combination effect of each phase

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