Bioplastics and biodegradability

Bioplastics or organic plastics are derived from renewable sources such as starch, vegetable oil and even chicken feathers. One such is poly(lactic acid) or polylactide (PLA) plastic.

Bioplastics can  also be made from ethane derived from plants. This is the same as ethane derived from oil and is used in the same way to make the same PET plastics.

YET The term bio-plastics is used to describe both types of plant derived plastic ie biodegradable and biomass derived. This has led to CONFUSION

Some bioplastics, like PLA plastic do biodegrade, indeed some are certified compostable. Others, like the plant derived PET plastic, do not biodegrade. Rather it shares the same long-lasting, non-biodegradable qualities as petroleum derived PET i.e lasts pretty much forever.

# For example, Coca-Cola’s PlantBottle simply replaces 30 percent of the ethanol in their normal polyethylene terephthalate (PET) plastic bottle with 30 percent plant-derived ethanol. This means the bottle is still considered PET and can be recycled even though it’s made with some plant material, but it still won’t biodegrade.”

In short, just because a plastic has been made from plants does not mean it is biodegradable.

Useful To Know

The case for and against plant derived PET plastics – great article here

Why most plastics don’t biodegrade

What is Ethane .

Biodegradable plastics are

  • Polyhydroxyalkanoates or PHAs  are linear polyesters produced in nature by bacterial fermentation of sugar or lipids. They are produced by the bacteria to store carbon and energy. ( taken from Wikipedia)
  • Poly(lactic acid) or polylactide (PLA)
  • Cellophane

Biodegradable/ degradable plastics.

Some conventional plastics are labeled biodegradable which may lead you to think they are, well, biodegradable! They are not. They have a an additive that makes the plastic fall apart, degrade, more quickly. And only in certain conditions. You can read more here



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