1. (polyimide heater)According to thermogravimetric analysis, the initial decomposition temperature of all aromatic polyimide is generally about 500 ℃. Polyimide synthesized from pyromellitic dianhydride and p-phenylenediamine has the highest thermal stability in polymers up to 600 ℃.
2. (polyimide heater)Polyimide can withstand extremely low temperature, such as no embrittlement in liquid helium at - 269 ℃.
3. (polyimide heater)Polyimide has excellent mechanical properties. The tensile strength of unfilled plastics is more than 100MPa, the Kapton film of homobenzene polyimide is more than 170Mpa, and the impact strength of thermoplastic polyimide (TPI) is as high as 261kj / m2. The biphenyl polyimide (upilex s) reaches 400MPa. As engineering plastics, the elastic modulus is usually 3-4gpa, and the fiber can reach 200GPa. According to theoretical calculation, the fiber synthesized by pyromellitic dianhydride and p-phenylenediamine can reach 500gpa, second only to carbon fiber.
4. (polyimide heater)Some polyimides are insoluble in organic solvents, stable to dilute acids, and general polyimides are not resistant to hydrolysis. This seemingly defective performance makes polyimides different from other high-performance polymers. That is, they can use alkaline hydrolysis to recover raw materials dianhydride and diamine. For example, for Kapton film, the recovery rate can reach 80% - 90%. Changing the structure can also obtain varieties that are quite resistant to hydrolysis, such as boiling at 120 ℃ for 500 hours.
