What are Bioplastics?

Bioplastics are generally considered to be a form of plastics derived from natural sources such as wood (cellulose), vegetable oils, sugar or starch. The collective term "Bioplastics" is used to describe different concepts at the same time, often leading to confusion.

Make informed decisions when purchasing

The world of "green", like any other industry, has its own language. For the person trying to make conscious environmental changes to their life, it can get very confusing - taking for instance the terms degradable, biodegradable and compostable when used in relation to Plastics. There is a difference between the terms and it may play a role in your purchase decisions. In order to make more informed decisions,download our list of definitions.

A Plastic:

• May be degradable, but not biodegradable
• May be biodegradable, but not compostable
• May be biomass, but not biodegradable

Also:

• If described as degradable – it only fragments and does not totally disappear [e.g. UV affected plastics film]
• If described as biodegradable – involves microorganisms that consume the fragments treating them as a food source
• If described as biodegradable – it can be either oxo-biodegradable or hydro-biodegradable
• If described as compostable – means it degrades in a commercial / industrial composting facility under strict composting conditions and must disintegrate rapidly and must be designed to degrade and form compost. The action is a biological process. This is not the same as home composting (where there is insufficient heat to decompose biomass products.)
• If bio-based: it can be made from sugar cane derived ethylene and then it behaves as a petro plastic – or – it can be made from starch, etc and then it is a hydro-biodegradable material very different to a petro plastic.
• If bio-based: the final product may be mixed with up to 50% of synthetic plastics from oil – and therefore will not behave like a typical biomass product based solely on starch, etc derived from renewable resources.
• Bio-based and bio-degradable are NOT the same thing.
• Biodegradability does not mean that: “it won’t harm the environment”
• Biodegradable doesn’t readily decompose in a land fill.
• Always look at both of the material source [e.g. is it renewable source or oil, etc] AND the desired functionality [e.g. degradation, biodegradability or compostability]

Downloads:

The PFSA's view on Bio-degradable plastics in recycling

Degradable - Definitions

Bioplastics

A very small amount of pro-degradant additive is introduced into the conventional manufacturing process, thereby changing the behavior of the plastic. The plastic should be consumed by bacteria and fungi after the additive has reduced the molecular structure to a level which permits living micro organisms access to the carbon and hydrogen. The material has then ceased to be a plastic and has become a food source. This process should continue until the material has biodegraded to nothing more than CO2, water and humus. It does not leave fragments of petro polymers in the soil.
Oxo biodegradable plastics are currently made from naptha, which is a by product of oil refining, and oil is of course a finite resource.

Defra (Department for Environment, Food and Rural Affairs) in the UK commissioned Loughborough University to review the environmental effects of oxo-degradable plastics.

In particular, to assess:

• The extent to which and timefram/e within which oxo-degradable plastics degrade or biodegrade
• The effects of the degradation or biodegradation of oxo-degradable plastics in the natural environment (e.g. soil, water) and different disposal facilities (e.g. recycling, industrial composting).

The study was carried out over 12 month period, involving an in-depth review of current research as well as consultation with manufacturers, retailers, trade bodies and waste treatment industries. Policy representatives and experts from DECC, Defra, the National Non-Food Crop Centre (NNFCC) and the Waste and Resources Action Programme (WRAP) have been involved throughout the research.

Downloads:

UK Assessing Envir Impacts of Oxo-degradable Plastics across their Life Cycle Jan 2010

UK, Defra, Enviro Impact of Oxo-degradable Plastics Jan 2010

UK, Defra, Oxodegradable Plastics Q&A

To see the final report click here. 

Other reading on this issue:

The use of oxo-degradable additives - It has been said that we should aim to improve the quality of the environment, not just protect it. New technology is one way of achieving this. But do the drawbacks of some technologies overshadow their advantages? An interesting view appeared in a recent copy of ICIS Connect Magazine (www.icis.com)

The plastics recycling industry and biodegradable films. SAPRO insists that the use of biodegradable additives in plastic film be stopped immediately.