35.3.3—Biodegradable polyesters and polyamides

Polyesters contain ester bonds and polyamides contain amide bonds. Water, acid or alkali can hydrolyse these polar links, so such polymers can be more biodegradable than poly(alkenes) under suitable conditions.

Hydrolysis rate depends on accessibility, temperature, pH and polymer structure. “Biodegradable” is a conditions-dependent claim, not an instant disappearance label.

An ester link can split into an alcohol and carboxylic acid (or carboxylate in alkali); an amide link gives an amine/ammonium product plus acid/carboxylate.

The presence of an ester or amide makes hydrolysis possible, not automatically rapid in every environment.