Introduction:
Science is one of the world's leading academic journals. Aerogel experts in the field said that aerogel is the only material that has landed on a large scale in the actual commercial scene among the ten new materials selected by Science magazine. Why is aerogel so feasible among so many materials? What are the advantages of aerogel?
Body text:
Experts in the aerogel field believe that aerogel can be understood as a nano version of a porous sponge, and the volume of all pores together accounts for the vast majority of the entire aerogel volume, even up to more than 99%. Aerogel based on special structure has more advantages than traditional materials.
High specific surface area, high porosity, nanoscale pores, low density and other special microstructure characteristics, so that aerogel has stable chemical properties, low thermal conductivity, strong
adsorption force, wide use temperature range, long service life and other excellent properties.
Thermal insulation performance
The porosity of aerogels is more than 90%. Due to the very small pore size in the structure, the flow of gas through it is restricted, thus reducing the path of heat conduction. In addition, pores can effectively prevent the propagation of thermal radiation, and in general, the porous structure plays a key role in improving the thermal insulation performance of aerogel. Therefore, aerogel has a low thermal conductivity and a high thermal resistance value, which has a significant effect in reducing heat transfer.

图源兰州大学

In addition, the independent structure of aerogel brings no convection effect, infinite shielding plate effect, infinite path effect, effectively prevent air convection, reduce heat radiation and heat conduction:
1) No convection effect: aerogel pores are nanoscale, and the internal air loses the ability to flow freely;
2) Infinite shielding plate effect: nanoscale porosity, porosity wall infinite, radiation heat transfer to the lowest;
3) Infinitely long path effect: heat conduction is carried out along the stomatal wall, and the nanoscale stomatal wall is infinitely long.

图源网络

In January, China Railway First Group Co., Ltd. said that the steam pipe network project in Xinxiang, Henan province, has been fully accepted. The steam pipe network has high requirements for anti-corrosion and heat preservation, and its pipes are made of high temperature centrifugal glass wool and nano aerogel composite heat preservation materials. Wang Xing, technical director of the project, said that the thermal insulation effect of nano aerogel is 2-5 times that of traditional thermal insulation materials, which can greatly improve the construction quality and construction efficiency and reduce construction costs.
Fire prevention
The very low thermal conductivity can make the protected substrate less than its own ignition point. The fire resistance of aerogel is also based on its special structure. Think of aerogel as a nanoscale version of a porous sponge. Its pore size is basically 20-50 nm micropore size, the air molecule size is about 70 nm, greater than the diameter of the aerogel material pores, so the air flow efficiency on the aerogel is extremely low, the heat insulation performance is very good, can reach class A non-combustible.
Light weight
In addition to its own light weight, the "light weight" performance of aerogel is also related to its thermal insulation performance. Compared with traditional thermal insulation materials, aerogel has lower thermal conductivity and higher heat resistance temperature, and the thickness of aerogel is less than 1/3 of that of other materials to achieve the same thermal insulation effect. Under the same insulation effect, the amount of aerogel is less, the thickness is thinner, the heat dissipation area is smaller, the thermal efficiency is higher, and the space is saved to the maximum.
Strong weather resistance
Aerogel as a whole hydrophobic, hydrophobic rate can reach 98% and above, which is based on the aerogel and super hydrophobic modifier mixed to achieve. It is not easy to absorb water and disintegrate, not easy to be damaged by changes in environment, temperature, etc., and its service life can reach more than 10-15 years, which is 3-5 times longer than that of traditional thermal insulation materials. The reason why the development of aerogel has entered the "fast lane" is that in addition to the promotion of external policies, norms and other factors, it is also inseparable from its own excellent performance. This is also why the application field of aerogel has gradually expanded to the downstream and become a new material for large-scale landing.