1, wholly aromatic polyimide by thermal gravimetric analysis, it begins to decompose at a temperature of generally about 500 ℃. Biphenyl dianhydride and p-phenylenediamine synthetic polyimide, the thermal decomposition temperature of 600 ℃, is one of the highest in the thermal stability of the polymer species to date.
2, polyimide can withstand very low temperatures, such as not rattle at -269 ℃ of liquid helium.
3, the polyimide has excellent mechanical properties, tensile strength unfilled plastics are more than 100Mpa, pyromellitic polyimide film (Kapton (R)) is 170Mpa or more, and biphenyl type polyimide ( Upilex S) reach 400Mpa. As a plastic, elastic modulus generally 3-4Gpa, 200Gpa fibers can be achieved, according to theoretical calculations, pyromellitic dianhydride and p-phenylenediamine synthetic fibers up 500Gpa, second only to carbon fiber.
4, a number of varieties of polyimide insoluble in organic solvents, acid stable, generally little hydrolysis species, this seemingly shortcoming performance while filling different from other high-performance polyimide polymer a greatcharacteristics, i.e., the raw material can be recovered by alkaline hydrolysis dianhydride and a diamine, for example Kapton film having a recovery of up to 80% -90%. Changing the structure can be obtained relatively hydrolysis species, such as to withstand 120 ℃, 500 Xiaoshi boiled.
5, the thermal expansion coefficient of the polyimide in 2 × 10-5-3 × 10-5 ℃, wide as the thermoplastic polyimide 3 × 10-5 ℃, biphenyl type up 10-6 ℃, individual species can reach 10-7 ℃.
6, polyimide has a high resistance to radiation performance, the film after 5 × 109rad fast electron irradiation strength retention was 90%.
7, a polyimide having good dielectric properties, dielectric constant of about 3.4, the introduction of fluorine, or nano-sized air dispersed in the polyimide, the dielectric constant can be reduced to about 2.5. 10-3 dielectric loss, dielectric strength 100-300KV / mm, wide as the thermoplastic polyimide 300KV / mm, volume resistivity of 1017Ω / cm. These properties over a wide temperature range and frequency range is still maintained at a high level.
8, polyimide polymer is self-extinguishing, low smoke.
9, the polyimide in a high vacuum gas rarely decentralized.
10, polyimide non-toxic, can be used to make tableware and medical equipment, and can withstand thousands of sterilization. Some polyimide also has good biocompatibility, e.g., blood compatibility test in a non-hemolytic, non-toxic in vitro cytotoxicity assays.