Aliphatic polyesters are biodegradable but often lack in good thermal and mechanical properties. While, vice versa, aromatic polyesters (like PET) have excellent material properties, but are resistant to microbial attack. Typical aliphatic polyesters include polyhydroxy butyrate, polycaprolactone, polylactic acid and polybutylene succinate. Aliphatic polyesters degrade like starch or cellulose to produce non-humic substances such as CO2 and methane. They can be processed on conventional processing equipment at 140-260 °C, in blown and extruded films, foams, and injection moulded products.