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For the application of adhesives in the aerospace industry

for the application of adhesives in the aerospace industry

April 10, 2020

adhesives: they have been used more and more widely in aerospace products, mainly because aerospace products mostly use light alloys, honeycomb structures and composite materials. However, aerospace products are used in harsh environments and have higher requirements for adhesives. They need to be able to withstand ultra-high temperature, temperature alternation, high vacuum Ultra low temperature, thermal cycle, ultraviolet light, charged particles, micro meteorites, atomic oxygen and other environmental tests. Specifically for the use of adhesives in the aerospace industry, the adhesive research institute has developed more than 100 kinds of special adhesives and sealants, mainly including polyurethane oxygen resins, organosilicon, acrylate, organic boron adhesives, etc., most of which have been used in China's launch vehicles, satellites, spacecraft and other aerospace products. Class, phenolic resin class,

here we mainly introduce high-temperature and low-temperature resistant adhesives

I. high temperature resistant adhesives

high temperature resistant adhesives generally refer to adhesive coatings that can be used at temperatures above 150 ℃. This kind of adhesive mainly includes modified multifunctional epoxy resin (EP), phenolic resin, silicon (or boron) containing polymer, aromatic heterocyclic high temperature resistant polymer and inorganic adhesive

pi adhesive is a high temperature resistant structural adhesive with the earliest development, the widest application and the best comprehensive performance. After curing at 300 ℃, it has good heat resistance and shear strength at 300 ℃ ~ 400 ℃. It can be used for a long time at 230 ℃ and can withstand a high temperature of 550 ℃ in a short time. It has the advantages of good low temperature resistance, solvent resistance, wear resistance, flame retardancy and extremely low coefficient of thermal expansion. The shear strength of PEEK adhesive developed by Jilin University exceeds 13Mpa at room temperature and 150 ℃

bismaleimide (BMI) is a kind of crosslinked PI with excellent performance, which has excellent high temperature resistance and moisture resistance. When BMI is introduced into epoxy resin, due to the different polymerization mechanism and compatibility between them, interpenetrating structure or two-phase system may be formed in the polymerization process, so as to achieve the purpose of toughening and improving heat resistance. Cyanate ester modified BMI adhesive can work for a long time at 230 ℃, and its shear strength is more than 13Mpa. Adhesive j-223 for high temperature resistant radome can be cured at 100 ℃, and the shear strength is 0.5MPa at 500 ℃

II. Low temperature resistant adhesive

low temperature resistant adhesive refers to an adhesive that can be used in ultra-low temperature environment and has sufficient strength. It is usually prepared from Pu, EP modified PU, PU and PA modified EP and other main materials. At present, the low-temperature adhesives that can be used at -253 ℃ for aerospace products in China mainly include nhj-44 adhesive, polyurethane modified epoxy adhesive, dwj-46 adhesive matching with the expansion coefficient of polyimide and aluminum storage tank, which is developed by the Institute of aerospace materials and technology and is used for liquid hydrogen liquid of launch vehicles. The core of liquid hydrogen liquid is to promote interconnection, cloud computing, big data, IOT and other modern manufacturing industries, Among them, nhj-44 adhesive is completely consistent with the performance index of mmma-132al structural adhesive, which is said to be the fastest and easiest one to print flexible materials on the market. Low temperature heat conductive insulating adhesive for bonding the surface temperature sensor of hydrogen and oxygen engine, with a thermal conductivity of 0 7W/m·K。 Dw-1 polyether polyurethane adhesive and dw-3 tetrahydrofuran polyether epoxy adhesive of Shanghai synthetic resin research institute are also applied according to the national standard

special sealant is the most widely used in aerospace.

sealant can not be prefabricated according to shape and size in advance, so its use technology is particularly important. Silicone sealant is widely used in aerospace industry. Many aerospace products need seals that can withstand 300 ℃ for a long time, over 400 ℃ for a short time or over 1000 ℃ for an instant

at present, China has high-grade one-component and two-component Pu sealant, which is mainly used for the pouring and sealing of waterproof electrical connectors, cable ends and plugs, circuit boards and other electrical components of aerospace products

although significant progress has been made in the development of adhesives for aerospace products, at present, some key materials needed by the aerospace industry still rely on imports, and the performance and quality of some materials are still unstable. Future lunar exploration projects, long-term resident space stations, deep space exploration, etc. (3) there will be many new demands for special adhesives due to the failure or damage caused by the transformation, decomposition and assembly of products, All these require the continued efforts of scientific and technological workers engaged in the preparation and application of adhesives

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