Airgel related presentations
Aerogels are the lightest solid material in the world, also known as \”blue smoke\”, \”frozen smoke\”, \”solid smoke.\” In which a set number of excellent properties, such as ultra-low thermal conductivity, sound propagation speed, dielectric constant and refractive index, high energy absorption, specific surface area and porosity transparent, in national defense, aerospace, nuclear and civilian areas have extensive and great prospect and value, known as \”change the world of magical material.\”
[scbutton link = \”#\” target = \”blank\” variation = \”blue\”] minimum density solid ( 7 × 10²) minimum aperture (~ 5nm) maximum the aperture ratio (> 99.9%) of the lowest thermal conductivity (<0.015w/m·k）
最低的损耗角正切（ 7 × 10 ^ 6) the maximum acoustic impedance (10 ^ 6 kg / ㎡s) broadest range of refractive index (116%) of the lowest Young\’s modulus amount (<10^5 N/M²）
airgel origin and development
(a) airgel was invented in the United States
aerogels are invented by Dr. Kistler in 1931 at Stanford University in the United States. it is the reason why the inventor the named aerogels, mainly gel replaced with air, i.e. a situation without breaking the gel structure of the solid, the liquid component replaced with air out of the colloid. Although this material has a number of interesting strange nature, however, because of the airgel manufacturing process complicated and expensive to manufacture other reasons, is not yet found in addition to the value of airgel, has not aroused attention.
(b) of military demand-driven airgel [123 ] until the 1970s, with the support of the French military propellant rocket project, Stanislaus Teichner, who find a new gel synthesis methods, significantly shorten the preparation period airgel, the airgel advance in aviation after the aerospace, defense and military fields of application. in the 1980s, the United States Berkeley Lab Russo, who developed a more practical use of TEOS and carbon dioxide supercritical drying technology, just pushing and commercialize airgel production possible. after entering the 1990s, setting off a boom in the world\’s first airgel, the US \”Science\” magazine as one of the Top ten airgel science.Promote the use of airgel in the aerospace, defense industry and the nuclear industry, such as the United States NASA\’s \”Stardust Program\”, \”Mars lander Plan\” projects. In the 21st century, in 2002, Aspen system company under NASA (NASA) created the world\’s first commercial production of airgel insulation material of Aspen Aerogel company, began marketing application airgel in civilian areas . Subsequently, the United States through the acquisition of the German company Cabot airgel technology has begun commercial production of transparent airgel particles, to promote the application of the depth of airgel, the application on a higher level. In recent years, the United States Nanopore company, Aerojet companies, as well as the EU\’s German company BASF, Hoechst company also added to the commercial application development airgel.
(c) of airgel latecomers
of Tongji University for the first time introduced in the aerogels study the nineties the country, followed by the National Defense University, Tsinghua University, Harbin Institute of Technology, Shandong University, Nanjing University, Zhejiang University, Central South University and many other colleges and universities have entered the airgel research. Shaoxing Nano Tech 2004, the company began commercial activities involved in the airgel, followed by Guangdong Egypt Lisheng Tech involvement airgel industry, which is China\’s first involvement in the airgel commercial enterprises. At present, there are dozens of companies involved in the airgel industry, but most of all relates to the technical field of fiber composite airgel insulation material. 2013 South University Dr. Lu Bin team tackled the airgel worldwide problem – Large full transparent preparation technology and high cost problems airgel, and with the Hunan Yi-feng New Materials Technology Co. opened a high-end transparent airgel country the industrialization process. With the scale of production increase, the future is still greatly reduce the cost of space, will greatly accelerate the commercialization of high-end airgel.
airgel Superadiabatic principle
1, a zero convection effect
Theoretical studies have shown that, when the pore size is less than 70nm airgel, due to the interaction between the air and the thin skeleton nano air molecules lose the ability to flow freely, but relative nanometer thin adhering to the backbone, resulting in an extremely low ability of thermal convection airgel.
2, a thermal barrier effect of nano-thin skeleton
configuration of the heat conduction along the mainNano-thin skeletal airgel into a three dimensional network structure is, since the skeleton thin (~ 1nm), Further further extended heat transfer path, resulting in heat transfer capability of the airgel near the bottom limit.
3, the barrier effect of multi-wall