Humid ageing of polyetherimide: Chemical and physical interactions with water - Polyimides and Other High Temperature Polymers - page 256

Figure 2. FTIR spectra of virgin PEI sample and of samples immersed in water at 180°C.

3.1.1. Discussion
The hydrolysis process can be described as:

This process is accompanied by:

- Mass gain (18 g/mol corresponding to the incorporation of water during the

chain scissions),

- Formation of acid and amide groups.