For the application of adhesives in the aerospace industry.

Adhesives:
has become more and more widely used in aerospace products, mainly because most of the aerospace products use light alloys, honeycomb structures and composite materials, but aerospace products use harsh environment, the requirements for glue is higher, need to be able to withstand ultra-high temperature, temperature cross-change, high vacuum, ultra-low temperature, thermal circulation, ultraviolet rays, charged particles, micro meteorites, atomic oxygen and other environmental tests. Specifically for the aerospace industry, adhesive research and development of more than 100 kinds of special adhesives and sealants, including polyurethane oxygen resins, silicones, acrylics, organic boron adhesives, the vast majority of which have been used in China's launch vehicles, satellites and spacecraft and other space products. Classes, phenolic resins,
here for everyone to introduce high temperature and low temperature resistant adhesives
One, high temperature adhesives
high temperature adhesives usually refers to the adhesive can be used at temperatures above 150 degrees C . These adhesives mainly have modified multi-official energy epoxy resin (EP), phenolic resin, silicone (or boron) polymer, aromatic ring high temperature polymer and inormeric adhesive.
PI adhesive is the earliest, most widely used and best comprehensive performance of high temperature-resistant structural adhesive, after 300 degrees C curing, in 300 degrees C to 400 degrees C conditions with good resistance Heat and shear strength, can be used for a long time at 230 degrees C, short-term resistance to 550 degrees C of high temperature, with better resistance to low temperature, solvent resistance, wear resistance, flame retardant and very low coefficient of thermal expansion and other advantages. The polyether ketone alamide adhesive developed by Jilin University has a shear strength of more than 13MPa at room temperature and at 150 degrees C.
double Malayamide (BMI) is a class of high-performance cross-linking PI, which combines high temperature and humidity resistance. When BMI is introduced in epoxy resin, due to the different polymerization mechanism and compatible of the two, the interoperability network structure or two-phase system may be formed in the polymerization process, thus achieving the purpose of toughening and improving heat resistance. Cyanate modified BMI adhesive can be long-term work at 230 degrees C, shear strength of more than 13MPa. High temperature antenna cover with adhesive J-223 can be cured at 100 degrees C, 500 degrees C shear strength of 0.5MPa.
II, low temperature adhesive
low temperature adhesive refers to the ultra-low temperature environment can be used and has sufficient strength of adhesive, usually by PU, EP modified PU and PU and PA modified EP and other main materials. At present, the domestic low-temperature adhesives used in aerospace products can be used at -253 degrees C mainly for the launch vehicle liquid hydrogen liquid oxygen tank co-bottoming and insulation layer bonding NHJ-44 glue, polyurethane modified The performance index of NHJ-44 glue is exactly the same as that of the U.S. federal standard MMMA-132Al structural glue, etc., such as epoxy gel, DWJ-46 glue, which matches the expansion coefficient of polyimide and aluminum storage tank. Low temperature thermal insulation for hydrogen and oxygen engine surface temperature sensor bonding, thermal conductivity 0.63-0.7W/m. K. DW-1 polyurethane glue and DW-3 tethydrofuran polyether epoxy glue of Shanghai Synthetic Resin Research Institute are also used.
most widely used in aerospace is the special sealant
sealants are often not prefabriced in shape and size, so their use of process is particularly important. Silicone sealants are widely used in the aerospace industry. Many aerospace products require long-term resistance to seals of 300 degrees C, short-term resistance to seals above 400 degrees C, or instant resistance to seals above 1000 degrees C.
At present, China has high-grade single-component and two-component PU sealants, mainly used in aerospace products waterproof electrical connectors, cable ends and plugs, circuit boards and other electrical components such as potted.
Although significant progress has been made in the development of adhesives for aerospace products, some of the key materials needed by the aerospace industry are still dependent on imports, the performance and quality of some materials are not yet stable, and there will be many new demands for special adhesives in future lunar exploration projects, long-term stationing on space stations, deep space exploration and other aerospace projects, all of which require the continued efforts of scientific and technological workers engaged in adhesive preparation and application.
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