6.2.3 (b) Hydrolysis of Polyester and Polyamides

(b) the acid and base hydrolysis of:

(i) the Ester groups in Polyesters

(ii) the Amide groups in Polyamides

Hydrolysis is to break up a substance using water.

Hopefully, you recall that making Esters and Polyamides forms water (unless using Acyl Chlorides in the place of Carboxylic Acids) - Hydrolysis is the reverse process.

Hydrolysis is a very slow process without the addition of a catalyst - Hot concentrated Acids or Alkalis are both able to act in this way.

Be careful,though, once the Condensation Polymer has been broken down into its monomers the catalyst may react with the functional groups in the monomers.

Notice that the Acid groups on the Dicarboxlic acid forms the Sodium Salt after reacting with the NaOH catalyst.

If you need the Dicarboxlic Acid you would have to react with another acid.

Again, the Acid groups on the Dicarboxlic acid forms the Sodium Salt after reacting with the NaOH catalyst.

And this time the Amine groups on the Diamine are protonated by the H⁺ in the Acid catalyst.

The addition of more base would remove the extra Hydrogen ions.