Polyimide is a kind of polymer containing phthalimide ring in the main chain, especially the polymer with skin imine ring structure.The title of this paper is polyimide, abbreviated as PI. With the increasing demand for material properties by science and technology, polyimide is used as a new polymer special engineering material.Because of its unique thermal stability, high strength, high modulus, insulation and anti-aging properties, it has been widely used in many fields,like aerospace, microelectronics, nano, liquid crystal, separation membrane, laser and other fields
Development of polyimide materials:
In 1908, Bogert and Renshaw heated 4-aminophthalic anhydride in the laboratory ，they found water is generated in the reaction process, accompanied by the appearance of brown solid material, which is the first time in human history to synthesize polyimide. However, due to the limitation of science and technology, polyimide did not get enough attention at that time. Up to 1955, scientists Edwards and Robson of DuPont company developed benzene type thermosetting polyimide film through years of hard work, and applied for patent. Because of its excellent chemical stability, high temperature resistance, tenacity, wear resistance, flame retardancy and electrical insulation, Kapton film is widely used in electrical insulation of electric motors, magnetic wires, aircraft and missile wiring and cables, and can be used as fire protection of aircraft and ships, which once occupied 70% of the market share. So far, the major companies have increased the research and development of polyimide, developed a variety of types of polyimide products. In 1964, Amoco company successfully developed PAI and used it to produce AI. Subsequently, DuPont company successfully developed the molding plastics with the material of polyphthalimide resin.
The development of polyimide films in Asia is relatively late, but it has developed rapidly in the last decade. Up to 2000, there have been more than 20 types of commercially available phthalimides. Due to the special properties and applications of polyimides, the global demand for polyimides is expected to increase at an average rate of about 10% in the next few years. The research on polyimide in China started in the 1960s. After more than 50 years of development, polyimide has made great progress in China. In 1999, the production capacity was about goo tons, and by 2006, the production capacity had reached 1300 tons. Among them, nearly 80 tons were exported to Korea, Russia and Southeast Asia every year. The export products were mainly used in insulating film and printing Brush the circuit board. In the field of polyimide resin and composite material research, China has a high level.http://www.china-polyimide.com