Oxo-biodegradable plastics are traditional (non-degradable) plastics such as PE, PP and PET, mixed with a small percentage of a pro-degradant additive during the manufacturing process. According to the Oxo-Biodegradable Plastics Association, this breaks the molecular chains in the polymer, and at the end of its useful life the product falls apart. After the additive has reduced the molecular weight to a level which permits micro-organisms access to the carbon and hydrogen, the fragmented product is consumed by bacteria and fungi.
EPI Environmental Technologies, for example, has incorporated its oxo-biodegradable technology into 150 applications. The company develops, manufactures, distributes and sells chemical additives to manufacturers of finished plastic products in the packaging, agricultural and composting industries. The principal chemical additives are its oxo-biodegradable plastic additives, which it calls Totally Degradable Plastic Additives (TDPA). It presents a strong voice for the biodegradability of oxo-biodegradable plastics.
EFI's plastic bag test shows the degradability of oxo-biodegradable vs normal plastic bags.
Other experts complain about missing scientifically based evidence from neutral, independent laboratories or certification bodies. Organic Waste Systems (OWS) in Ghent, Belgium, recognises that as long as this evidence is missing, critics will doubt that complete biodegradation is possible and call these products oxo-fragmentable.
Even the Oxo-Biodegradable Plastics Association admits that it is better to recycle these plastics “…the benefits of oxo-biodegradable plastic is that it can be recycled as part of a normal plastic waste stream. However, if the plastic is not collected it cannot be recycled, so it needs to biodegrade instead of accumulating in the environment…”
So, OWS and the Institute of Polymer Technology, University Stuttgart (IPT) are planning a multi-client study on oxo-degradable plastics.
The comprehensive laboratory testing programme will build on a desk research by OWS for Plastics Europe (2013). The laboratory tests, OWS claims, will ultimately prove or disprove whether such products are biodegradable.
In the first phase, a number of oxo-biodegradable plastic products available in the market will be abiotically treated. In the second phase, the fragmented parts will be used for further biodegradation testing according to internationally accepted ISO and ASTM standards.
It is possible to participate in this multi-client study. The contribution for this study is estimated at 10,000 Euro to 20,000 Euro per partner, depending on the number of interested companies.
More information can be found in the official proposal.
