The density of PI is 1.28-1.48g/cm3, with the imidization degree increasing, density will increase; when the containing side groups in the main chain, density will be smaller. PI has higher tensile, bending, compression strength, mechanical properties belonging to the middle and upper levels, the high modulus, especially at high modulus high is a prominent feature of its mechanical properties.
Creep resistant adhesive PI has excellent dimensional stability, which is very prominent.
The most prominent performance of PI is its heat resistance is high, the decomposition temperature of glass transition temperature, thermal performance have higher, and the continuous high temperature. Continuous working temperature is 250 ℃.
PI excellent electrical insulation properties, in a wide range of temperature dipole loss is quite small. It has the most excellent corona resistance, or is it because of two kinds of chemical reaction to generate Corona: oxidation active oxygen atoms decomposition; oxidation reaction of ozone, hydroxides are very resistant. PI belongs to the intermediate dielectric material.
PI has good stability for oils, organic solvents, dilute acid, but not resistant to strong oxidation with concentrated sulfuric acid and fuming nitric acid, also not alkali resistant type and superheated steam. Oxidative degradation occurred in the role of strong oxidants. Alkali and water vapor effect will make the PI imide ring opening and backbone fracture occurs, the resulting performance degradation.
Due to the large number of aromatic molecular chain of PI ring structure, which absorbs radiation ability is very strong, therefore has excellent radiation resistance, it can stand the neutron, electron, 7 rays, ultraviolet radiation, the radiation environment, the performance degradation is very limited.