English
The preparation method of the thin film is as follows: the polyamide acid solution is cast into a film, stretched, and then subjected to high-temperature acylation and amination. The thin film is yellow and transparent, with a relative density of 1.39-1.45. It has outstanding high temperature resistance, radiation resistance, chemical corrosion resistance, and electrical insulation properties, and can be used for a long time in air at 250-280 ℃. The glass transition temperatures are 280 ℃ (Upilex R), 385 ℃ (Kapton), and above 500 ℃ (Upilex S), respectively. The tensile strength is 200MPa at 20 ℃ and greater than 100MPa at 200 ℃. Specially suitable as a substrate for flexible printed circuit boards and insulation materials for various high-temperature resistant motors and electrical appliances.
physical property
Thermosetting polyimide has excellent thermal stability, chemical corrosion resistance, and mechanical properties, usually orange in color. The flexural strength of graphite or glass fiber reinforced polyimide can reach 345 MPa, and the flexural modulus can reach 20 GPa. Thermosetting polyimide has low creep and high tensile strength. Polyimide has a wide range of temperatures, ranging from minus 100 degrees Celsius to two to three hundred degrees Celsius.
chemical property
Polyimide has stable chemical properties. Polyimide does not require the addition of flame retardants to prevent combustion. Generally, polyimides are resistant to chemical solvents such as hydrocarbons, esters, ethers, alcohols, and chlorofluorocarbons. They are also resistant to weak acids but are not recommended for use in strong alkaline and inorganic acid environments. Some polyimides such as CP1 and CORIN XLS are solvent soluble, which helps to develop their applications in spraying and low-temperature crosslinking.