Polyimide
Overview
 

Polyimide (sometimes abbreviated PI) is a polymer
Polymer
A polymer is a large molecule composed of repeating structural units. These subunits are typically connected by covalent chemical bonds...

 of imide
Imide
In organic chemistry, an imide is a functional group consisting of two carbonyl groups bound to nitrogen. These compounds are structurally related to acid anhydrides. The relationship between esters and amides and between imides and anhydrides is analogous, the amine-derived groups are less reactive...

 monomers. The structure of imide is as shown. Polyimides have been in mass production since 1955. Typical monomers include pyromellitic dianhydride and 4,4'-oxydianiline
4,4'-Oxydianiline
4,4’-Oxydianiline is an organic compound with the formula O2. It is an ether derivative of aniline. This colourless solid is a useful monomer and cross-linking agent for polymers, especially the polyimides, such as Kapton.- Uses :...

.
According to the composition of their main chain, polyimides can be:
  • Aliphatic (linear polyimides),
  • Semi-aromatic,
  • Aromatic: R' and R" are two carbon atoms of an aromatic ring.
 
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