In the early 1940s, the electronics industry needed to find a suitable material to protect the radar antennas of military aircraft, especially the radar antennas on fighter planes and bombers. The use of radome is used to protect the influence of climate on precision electronic instruments. FRP has excellent radar wave transmission performance, sufficient mechanical strength and simple molding process, making it an ideal radome material. This is the first time in history that FRP has been used to make a radome, and it has greatly promoted the study of FRP materials.
In the 1960s, the application of FRP technology in the field of helicopters has made a breakthrough, such as West Germany M. B. B. The company developed glass fiber reinforced plastic rotor blades, which gradually replaced metal aluminum skin/aluminum honeycomb sandwich metal blades. However, due to the low modulus of FRP, high-strength aircraft structural parts cannot be manufactured.
In the early 1970s, with the successive appearance of boron fiber, carbon fiber, aramid fiber, etc., the specific stiffness, specific strength, fatigue resistance, etc. of these advanced reinforcing fibers were superior to metal materials, and composite materials composed of them to reinforce epoxy resin, It has been applied to the main structural parts (main bearing parts) of the aircraft.
For more than 10 years, considering the high prices of these high-grade reinforcing fibers, in order to use materials more reasonably, vigorously develop hybrid composites (Hybrid Composites) research.
It is represented by the application of composite materials in aircraft engines. Two jet engine manufacturing plants in the United States: General Electric—Aircraft Engine Group (GE-AEBG) and Pratt & Whitney, as well as other secondary contracting companies, are replacing metal with high-performance composite materials for aircraft engine parts. For example, many parts of the engine compartment system, such as thrust reversers, fan shrouds, and fan duct deflectors, are made of composite materials. For example, the shell of the engine imported air hood is made of carbon fiber epoxy resin premix (E707A) of American Polymer Company. It has a thermal oxidation stability of 177℃ and the surface of the shell is smooth like a mirror surface, which is conducive to the formation Laminar flow. Another example is that the FW 4 0O0 engine has 80 high-temperature air nozzle deflectors at 149°C, which are also made of carbon fiber epoxy prepreg.
In the environment below the limit temperature of 316℃, composite materials not only have better performance than metals, but also have high economic benefits. According to Boeing estimates, for every pound of weight loss of a jet airliner, the aircraft can save $1,000 over the entire life cycle. According to Fabrite’s estimate, about one million pounds of composite materials were used to manufacture jet aircraft engine parts in the United States for the first year, with sales of up to $50 million.
At present, the continuous use temperature of epoxy resin is below about 280℃. Recently, a multifunctional epoxy resin Tactlx742 of DOW Chemical Company, used diaminodiphenyl sulfone curing agent; the glass transition temperature of the finished product is Tg>310℃ , Can be used to manufacture jet engine parts.