Nano aerogel thermal insulation felt is a kind of controllable structure of nano porous lightweight material, it has the characteristics of nano structure ( pores 1 ~ 100 nm, skeleton particles 1 ~ 20 nm ), large surface area ( up to 800 ~ 1000 m2 / g ), high porosity ( up to 80 % ~ 99.8 % ) and so on. The unique structural characteristics of nano aerogel insulation felt make aerogel have singular properties in thermal, electrical, acoustic, optical and other aspects. The thermal conductivity of the nano aerogel thermal insulation felt can reach below 0.013 w / ( m k ), which is far lower than the thermal conductivity of air at normal temperature of 0.025 w / ( m k ). the nano aerogel thermal insulation felt is one of the best thermal insulation properties of all solid materials, and has the advantages of low density, water resistance, flame retardance, green environmental protection, acid and alkali resistance, corrosion resistance, difficult aging and long service life, which are incomparable to other traditional materials. the nano aerogel thermal insulation felt has high added value, so the nano aerogel thermal insulation felt is called a super thermal insulation material, and has great application potential in many fields, such as building energy conservation, environmental protection, aerospace, oil pipelines, solar heat collection and furnaces The main characteristics of the nano aerogel insulation felt ( fig. 1, table 1 ) are as follows:

1. Superior thermal insulation performance
 Due to the super thermal insulation performance of nano - pores, the total thermal conductivity of nano - aerogel insulation felt powder is less than 0.015 w / ( m k ), the total thermal conductivity of the block is less than 0.013 w / ( m k ), the total thermal conductivity of the powder is less than 0.003 w / ( m k ) under vacuum condition, and the total thermal conductivity of the block is less than 0.007 w / ( m k ), which is one of the materials with the lowest thermal conductivity in the field of high-temperature insulation in the world at present.
2. unique flame burn-through resistance
The nano aerogel thermal insulation felt is non-combustible and has unique flame burning resistance, and can bear direct burning of flame for a long time. Does not release harmful substances in high temperature or fire field, can effectively block the spread of fire at the same time, and provides more valuable time for fire escape.
3. good thermal stability
The thermal stability temperature of that nano aerogel thermal insulation felt is as high as 600 deg c ( the porosity of the nano aerogel thermal insulation felt is reduce above 700 deg c until the nano aerogel thermal insulation felt is sintered into dense SiO 2 ), and the nano aerogel thermal insulation felt has super hydrophobicity below 300 deg C..
4. excellent sound insulation
The nano aerogel thermal insulation felt also has the excellent performances of extremely low density, extremely low sound propagation speed, extremely low dielectric constant, extremely high porosity, extremely high specific surface area and the like, and is expected to become an environment-friendly high-efficiency thermal insulation and sound insulation lightweight building material by virtue of the excellent thermal insulation and sound insulation performance, and has wide and great potential application value in the field of building energy conservation.
5. better light transmission
The nano aerogel thermal insulation felt also has light transmittance, can effectively transmit visible light, and can effectively block infrared radiation at the same time, therefore, the nano aerogel thermal insulation felt can be used for buildings and can well take daylighting and energy conservation into consideration. 6. the nano aerogel thermal insulation felt with good chemical stability and environmental protection is mainly composed of synthetic SiO 2, is environment-friendly and non - toxic, can resist most acid-base environments except hydrofluoric acid for a long time, does not decompose and deteriorate, has extremely long service life under the conventional use environment, is a moisture - proof, mildew - proof, bacteria - proof, ultraviolet-resistant and overall hydrophobic property, does not cause deformation, has excellent heat insulation property and sound insulation property, and can be developed into a good completely recyclable ecological building material.