Why Nanopore Aerogel Material Is the Top Of Thermal Insulation Material?
Nanopore aerogel insulation material is by far the lightest solid known to mankind, is by far the best known thermal insulation properties of materials, the silica nanopore (1-50nm) structure, it has Low thermal conductivity (0.012-0.020w / mk), low density (1-100kg / m3), low dielectric constant (1-2.2), noncombustible, stable properties and other characteristics in the military, aerospace, aviation, telecommunications, Energy, construction, transportation and other fields have a wide range of applications.
From the macroscopic point of view, the essence of heat is the external manifestation of irregular motion of a large number of material particles. The hotter an object is, in fact, the more intense the movement of particles in the structure of the object. This movement in the gas is realized as the free movement of gas molecules; liquid in the liquid molecules into a group of liquid flow; in the solid material showed the movement of particles. To sum up: There are three ways to transfer heat, heat conduction, convection and heat radiation.
JODA silica aerogel composite insulation material can be a good way to suppress the three heat conduction.
1, the thermal conductivity of the barrier principle: the size of the thermal conductivity of solid materials, from the perspective of thermal insulation materials, only with the inherent thermal conductivity of the material itself, and the density of the material. In order to reduce the density of materials, the general insulation materials are taken to create pores. JODA company developed porous silica aerogel composite insulation materials, at this point to achieve the ultimate; the porosity of the material accounted for more than 90% of the total volume, which is extremely low density of materials, water only four points One around.
2, the principle of blocking the heat convection: Because most of the insulation materials contain a large number of pores, so the convection of gas contained within the pores of the thermal conductivity has become a key thermal conduction. According to the study, convective heat conduction is only related to the nature of gas and pore size. Different insulation materials use different ways to reduce the convection heat conduction. For example, polyurethane foams fill the pores with Freon gas, which has a thermal conductivity of only one-third of the air, resulting in superior thermal insulation. However, due to its serious damage to the ozone layer has been replaced by carbon dioxide, etc., but as carbon dioxide filled polyurethane material, there will be the problem of high thermal conductivity. Another approach to silica aerogel composite insulation is to reduce the pore diameter to reduce the thermal conductivity of air in the pores. After a special process made of this material, in which the average pore diameter of only 50-60 nm, about one-thousandth the diameter of the hair, while the average freedom of air molecules is about 70 nanometers. In such a small space, the air is almost unable to flow, thus inhibiting the air convection heat conduction.
3, the thermal radiation barrier principle: Due to the existence of a large number of tiny holes, the material has almost infinite wall, and these hole wall can be regarded as the radiation reflection and refraction surface. A millimeter thick silica aerogel composite insulation material contains tens of thousands of layers of reflective and refracting surfaces that provide a good barrier to radiative heat transfer. At the same time, in order to better restrain the radiation heat conduction of the material, the material adds some nano-scale anti-radiation substances, which can well reflect / absorb heat radiation. Therefore, the material for radiation heat conduction also has a good inhibitory effect.
After years of research and development, JODA has produced aerogel composites such as Aerogel Insulation Blanket, Aluminum Foil Aerogel Insulation Blanket, Carbon Fiber Aerogel Insulation Blanket, Aerogel Particles, Aerogel Powder and Aerogel Glass.