Properties Of Polyimide Films
1.Wholly aromatic polyimide by thermogravimetric analysis, the initial decomposition temperature is generally in the 500 ℃. From two to two of benzene anhydride and diphenyl amine synthesis of polyimide, thermal decomposition temperature reaches 600 ℃, is one of the highest species hitherto polymer thermal stability.
2.Polyimide is resistant to extreme low temperature, such as not in - 269 ℃ in liquid helium embrittlement.
3.Polyimide with excellent mechanical properties, tensile strength of unfilled plastics is above 100Mpa, thin films of polyimide (Kapton) is more than 170Mpa, and biphenyl polyimide (Upilex S) to 400Mpa. As engineering plastic, elastic modulus is 3 4Gpa, the fiber can reach 200Gpa, according to theoretical calculation, all two benzene anhydride and two benzene amine synthesis fiber can reach 500Gpa, second only to carbon fiber.
4.Several polyimides varieties are not soluble in organic solvents, the dilute acid stability, the general variety little resistance to hydrolysis, this seemingly shortcomings performance makes the polyimide has a lot of characteristics different from other high performance polymers, which can use the alkaline hydrolysis of recycled materials two anhydride and two amines, such as Kapton film, the recovery rate up to 80% - 90%. Changing the structure can also be quite hydrolysis resistant varieties, such as stand up to 120 ℃, 500 hours of water.
5.The thermal expansion coefficient of 2 * 10-5 to 3 * 10-5 ℃, Guangcheng thermoplastic polyimide 3 * 10-5 ℃, biphenyl type up to 10-6 ℃, individual species can reach 10-7 ℃.
6.Polyimide with high irradiation resistance, the film in 5 × 109rad fast electron irradiation strength retention rate was 90%.
7.Polyimide has good dielectric properties, introducing fluorine dielectric constant is about 3.4, or the air, nanometer size dispersed in the polyimide, the dielectric constant can be reduced to about 2.5. The dielectric loss of 10-3, the dielectric strength of 100 300KV/mm, Guangcheng thermoplastic polyimide 300KV/mm, volume resistance of 1017 Ω /cm. These properties can still maintained at a high level in the wide temperature range and frequency range.
8.Polyimide is self quenching of polymer, the low rate of smoke.
9.Polyimide in high vacuum outgassing rarely.
10.Polyimide is non-toxic, can be used for the manufacture of tableware and medical equipment, and can withstand thousands of times disinfection. There are some polyimide has good biological compatibility, for example, in the blood compatibility test for non hemolytic, cytotoxic activity in vitro experiments for non-toxic.