What is polyimide? What are the main varieties?
Polyimide, also known as PI, is an aromatic heterocyclic polymer with acyl imine groups in its main chain. Its general formula is as follows: Ar and Ar in the formula represent aryl groups. Polyimide can be divided into four categories based on the difference between Ar and Ar: the first category is polymers with aromatic and imine rings connected, the second category is polymers with heteroatoms in the dianhydride component, and the third category is polymers with heteroatoms in the diamine component, The fourth type is polymers containing heteroatoms in both dianhydride and diamine components. In addition, according to different production methods, polyimides can be divided into two categories: condensation type and addition type. At present, the main varieties of polyimides include benzene type polyimides, ether anhydride type polyimides, polyimide imides, and maleic anhydride type polyimides. Polyimide as an aromatic heterocyclic polymer.