High-performance engineering plastic refers to long-term use at above 150 ℃. With the development of mechanical and electrical manufacturing industry, high-strength, high modulus, dimensional stability, light, electrical insulation, wear resistance, self-lubrication and sealing materials requires more and more urgent. And polymer materials, in particular, but also has a high heat resistance of the plastic is to meet these requirements, in fact, this is a totally new class of materials. Since the 1970s, many developed countries have developed polymer main chain aromatic heterocyclic composed of such polymers both excellent mechanical properties and high temperature, fully able to meet the requirements of high-performance engineering plastics. The main varieties are polyphenylene sulfide, polyether sulfone, polyether ketone, polyarylene lipid thermotropic liquid crystal polymers and polyimide. An important common feature of these materials are easy to process by injection molding. Polyimide high performance engineering plastics should be a special breed. In addition to injection molding can also be carried out, the use of engineering plastics that require higher temperatures can only be used hot or even a special molding method. The polyimide because of its many varieties and is virtually the only way to manufacture a variety of materials available in this area.