Oxo-degradable vs. Biodegradable – A point of view!

An interesting answer to an article on a new line of oxo-degradable bags. The journalists of the Exchange Morning Post have mixed “oxo-degradation” and “biodegradation” – A common case!

Letter to the Editor:

Dear sir,

Your opening paragraph sums up the perpetuation of misconception, presumably due to ignorance on the part of the company launching these materials.

Article in question

As someone who has spent over 40 years in the plastics industry and 20 years in the specific area of degradable plastics- both UV “degradable” in the early 1990’s and then as a founder member of Natureworks llc PLA compostable products and the more recent formation of Jim lunt & Associates. LLC.; I must comment that it is exactly this type of article that not only appears to be factually incorrect but also adds to the increasing confusion by consumers.

Oxo degradable technology, whereby an additive is used to accelerate free radical “degradation” of plastics, has been around since the 1980’s and in fact the claims being made even then, were challenged as misleading and these products were subsequently removed from the marketplace.

Now with the public awareness of depletion of non renewable resources, filling up of Landfill space and the increasing concern over potential health issues associated with certain monomers in oil based plastics, we see this same technology once again being re introduced as a viable answer to some of these societal issues.

Your opening paragraph sums up the perpetuation of misconception, presumably due to ignorance on the part of the company launching these materials.

MONTREAL – ECO II Manufacturing is proud to announce the launching of a very new line of bags which are 100% oxo-biodegradable. The main quality of these products is that they are totally degradable in less than 2 years at a temperature of 45-C, which is the average temperature of landfills, in accordance with ASTM D6954-04. In ideal landfill conditions, these products disintegrate in as little as 12 weeks. The ordinary plastic bag, takes over 400 years.

Firstly, Oxo degradable – suggests degradation in the presence of oxygen. It is true that polyolefin’s such a PP and PE will fragment in the presence of oxygen and sunlight when the stabilizers added to the material to prevent such degradation have lost their efficacy. It is also true that some additives such as heavy metals and other materials, will accelerate this fragmentation. However, such fragmentation has repeatedly been shown to be purely due to breakage of the polymer chains. There has been no reputable evidence that microorganisms are involved in any of this degradation either in a aerobic compost or a anaerobic managed landfill environment . There is also no reputable evidence that these polymer fragments are attacked by microorganisms. There is actually no bona fide published evidence that in a sealed landfill, or municipal composting that these products containing such additives will degrade to simple biologically assimilative or their direct energy recovery components .

I find it surprising that this type of fragmentation is one again being associated with biodegradation- which is degradation of a plastic due to the action of microorganisms –either in aerobic or anaerobic conditions. I see claims being made once again with no supporting evidence.

I, along with many consumers and I believe, the whole emerging biodegradable /biobased plastics industry, would really appreciate seeing definitive supporting evidence that these products truly are attacked by micro organisms and actually do degrade into the basic components of carbon dioxide, water or methane in controlled and defined timescales.

Today the only accepted definitions of degradability accepted universally, are that the plastics degrade to give either carbon dioxide and water in aerobic conditions, or methane gas under managed anaerobic landfill conditions, constructed to create reusable energy.

Is such information available and will the company provide such information so its claims can be substantiated by the regulatory organizations who protect the public interest to understand the true facts?

I look forward to reading a future article with supporting evidence to the claims being made or at least an acknowledgement that this evidence is necessary for the consumer to really know what is the best choice to make

My best regards. Dr. Jim Lunt (Jim Lunt & Associates LLC)

Source

To learn more on “oxo-degradation” and “biodegradation”, some recent posts:

• En français
• En castellano

– Related posts / Billets à lire, en complément :

• Warning against oxo-degradable additives

• Peril of petroleum-based plastics – A point of view!

• Oxo-degradable plastics – A point of view!