PHA bioplastics: Characteristics
Brilliant at breaking down, tricky to process
What this tab covers The physical and chemical properties that set its grade, price and uses, with the commercial grades and the standards that define them.PHA's selling point is biodegradation outside industrial composting: in soil, home compost and seawater. Its weaknesses are cost, narrow processing windows (it degrades thermally near its melting point) and, for PHB, brittleness. Copolymers such as PHBV and PHBH, and amorphous PHA, address toughness.
Properties that matter commercially
| Property | Value / specification | Why it matters | Source |
|---|---|---|---|
| Biodegradation | home compostable and marine biodegradable for certified grades | The main reason to pay a premium | TUV and ASTM certification schemes (indicative) |
| Melting point | about 140-175 C depending on type (indicative) | Close to degradation temperature, so processing is tricky | indicative |
| Barrier | moderate oxygen and water barrier (indicative) | Useful for coatings | indicative |
Commercial grades
- PHB and PHBV (rigid)
- PHBH (Kaneka)
- mcl-PHA (flexible)
- Amorphous PHA (CJ aPHA)
- Compounds with PLA and PBAT
- Medical grade P4HB