Polyimide film has a highly cross-linked chemical structure

2023-03-27 10:12:09

Polyimide film is a polymer material formed by condensation of compounds such as imide and amide at high temperature. Its general chemical structure is shown in the figure below:

The basic structure of the polyimide film is composed of multiple benzene rings connected by imide bonds, and the four positions of A, B, C, and D can be changed through the design of the chemical structure. The molecular weight of polyimide film is generally between 10,000 and 50,000, and its crystallinity is very low, so that it can be prepared into films of various shapes and sizes.

1. High strength and rigidity

Due to the highly cross-linked chemical structure of polyimide film, it has high strength and rigidity. Its tensile strength can reach 200MPa, its yield strength can reach between 200 and 400MPa, and its relative flexural modulus can also exceed 30GPa. In addition, the hardness of the material is also very high, and its Young's hardness can reach 34GPa.

2. Excellent high temperature resistance

Polyimide film has excellent high temperature resistance and can run for a long time in a high temperature environment above 300 degrees. It has a very low coefficient of thermal expansion and is not prone to stress cracks during thermal expansion and contraction. In addition, the material has excellent yellowing resistance and is not prone to aging and ultraviolet radiation due to prolonged exposure to sunlight.

3. Good chemical stability

Polyimide film has good chemical stability to most common chemical solvents and acid-base media, and is not easy to be corroded and eroded. At the same time, the material will not be affected by metal ions and can be tightly combined with the metal surface.

4. Dielectric properties

Polyimide film has good dielectric properties, good insulation and electrical breakdown resistance, and can be widely used in the field of electronic devices.