PLA – a sustainable polymer
Polylactic acid or Polylactide (PLA) is a biodegradable, aliphatic polyester based on renewable resources. The feedstock for Uhde Inventa-Fischer’s PLA process is lactic acid.
The source of lactic acid is any raw material containing starch or sugar, such as corn, cereals, cassava, sugar cane or sugar beet. Lactic acid is expected to be sourced from non-food, cellulose materials within the next few decades.
Some properties of PLA polymer are listed here:
| Properties of PLA | |
|---|---|
| Crystallinity (%) | 10 - 40 % |
| Glass Transition Temperature (°C) | 55 - 60 |
| Melt-Index Range (g/10min) | 2 - 20 |
| Melting Temperature (°C) | 130 - 170 |
| Molecular Weight Mw (Daltons) | 100,000 to 300,000 |
| Specific Gravity | 1.25 |
End-of-life options
Different end of life options are conceivable which mostly depend on the final product application, the waste management system available and local conditions.
Chemical recycling offers a route back to a virgin product with the same high quality whereas mechanical recycling is useful when the degradation that results in loss of properties is not an issue.
Another option is incineration in order to recover the product's energy, which could also be called “green energy” due to the renewable resources and the balanced greenhouse gas statistics.
In addition, composting as an end of life option is closely linked to the product application as well as to the local waste management.
In summary, only a careful consideration of all facts and the utilization of cascades for the product and recycling cycle will result in a sustainable process.