Status airgel insulation coating and Future Directions
Airgel is an internal network structure filled with the gas, presenting the appearance of a very low density of the porous solid material. It is generally made up of a network of nanoparticles composed of mutually crosslinked, wherein the interior of the pores is mainly a microporous particles, mostly between the particles and the particles are macroporous or mesoporous on 2 nm. Its density is very low (3kg / m3), he was awarded the Guinness Book of Records \”the world\’s lightest solid\” title. Nanoporous airgel as a new structural material of solid material, having excellent lightweight properties, heat insulation, transparency, heat, fire and the like. from the components of the classification is to distinguish between aerogels most common way, a composite component into a single component and two categories. Single component oxide airgel comprising airgel (silica and non-silica), aerogels (resin matrix and fiber group), carbon airgel (carbonized plastic, carbon nanotubes, and graphene) , sulphides and other types of airgel airgel (single element, a carbide); airgel composite component comprises multicomponent airgel, airgel gradient and micro / nano-airgel composite. Wherein the silicon airgel, carbon airgel, and silica airgel most common. Silica airgel unique microstructure nanostructure to have a low density, high surface area and high porosity characteristic. These features make in terms of thermal, optical, electrical, acoustical, etc. have excellent properties unique, efficient and can be used as thermal insulation material, the acoustic impedance of the coupling material, a low dielectric insulating material, the catalyst and catalyst carrier, wherein the insulation and efficient insulation materials applied more widely. The main form of silica airgel applications in the field of thermal insulation are four kinds: airgel powder, airgel particles, airgel blankets, plate airgel, airgel glass, wherein the coating industry, mainly airgel powder coatings on the basis of the airgel.
airgel composition and properties of aerogels
airgel insulation coating to self-crosslinking acrylic emulsion forming composition, of SiO2 aerogels, hollow glass beads, potassium titanate whisker as a filler , prepared by the cooperation of a variety of additives. Spraying a thin layer of coating having nanopores insulation, fire safety, environmental protection and energy saving, cost advantages, and other advantages no loss risk. Test results show, good insulation 1mm thick insulation coating airgel insulation than 8cm thick polystyrene foam board.
airgel insulation Principle
of heat conduction from the high temperature zone is always transmitted to the lower temperatureDelivery, solid heat conduction heat conduction, air convection heat conduction, radiant heat in three ways. It features airgel insulation coating is: capable of above three pathways for effective heat barrier or shield. In the coating component, heat plays a key role in the nano-SiO2 aerogels, followed by potassium hexatitanate whiskers and hollow glass microspheres. Nano SiO2 airgel is a very good thermal insulation properties of lightweight amorphous nanoporous solid insulation material, having a porosity as high as 80% to 99%, a typical hole size of 2 ~ 50nm, the average pore size of 20 nm, a specific surface area of 600 ~ 1000m2 / g, an apparent density of 0.003 ~ 0.35g / cm3, the thermal conductivity at room temperature can be as low as 0.013W / (mk), even at high temperature 800 ℃, the thermal conductivity is only 0.043W / (mk), and does not decompose at a high temperature, no harmful gas evolution, pure green material, which disadvantage is the low strength, brittle, difficult to use alone. The nano-SiO2 airgel and hollow glass microspheres and aluminum silicate fiber compounded in crosslinking the elastomeric film material, can greatly improve the mechanical properties of the coating.
Aerogels status quo standard
airgel insulation coating is no current industry standard, most local enterprises reference insulation coatings GB \”GB / T 25261-2018 building heat reflecting coatings. \”
has been released and is currently part of airgel insulation coating standards being developed are as follows: Community standards
- Construction Engineering Consulting Co., Ltd. Kai-standard editor of the \”T / SCDA 032-2019 modified airgel insulation paste applied technical standard external insulation system. \” Click to download
- \”airgel insulation coating architectural application of technical regulations\” Hunan Construction Technology and Building Energy Conservation Association prepared.
- China Academy of Building Standard Design Co., Ltd. and Shanghai Building Materials Co., Ltd. and South Africa led the development of China Engineering Construction Standardization Association standard \”airgel insulation thick coating systems\” and \”thick airgel insulation coating systems application of technical regulations. \”
- Limited by the China Building Standard Design and Research Institute, Shenzhen and Yang Ning Technology Co., Ltd. Shanxi new material limited liabilityAny company drafted the \”airgel new building materials systems\” and \”airgel new building materials systems application of technical regulations\” standard. Airgel new building system is a thick insulating coating systems airgel, airgel blankets, airgel insulation wall, etc. Since the composite through a special process used in the construction field, up to the national energy requirements in the construction field. Technical specification for application of new building materials airgel system is designed to solve the new building\’s design, construction and inspection and other technical issues.
direction of development of airgel
Currently the main application areas airgel coating products are building insulation, because this area is relatively the easiest promotion, technical difficulty is the lowest field, while holding the metal is relatively difficult to many devices, mainly due to the current airgel insulation coating adhesion is not high, heat resistance, etc. also need to continue optimization. In addition to silica airgel, but also other types of aerogels promising ceramic powder as an airgel, airgel graphene gradually applied to the coating to improve the current airgel silica airgel insufficient heat resistance, strength, future product development direction should still like to have a comprehensive performance of product development, such as architectural airgel insulation coatings to be integrated with insulation, waterproof, anti-aging ability, can under no circumstances topcoat directly applied to EIFS; products such as insulation applied to both the field device needs heat, corrosion and fire comprehensive functions, these products are more technical content.