additives feature | Oxo-degradable debate
Some plastics recycling organisations have expressed concerns about the impact of oxo-degradable additives on the quality of recyclate
acceptability must be correlated with the environment and with the problems to be solved. The risk associated with
the process of working in the opposite direction (from the material to the environment) is to lose credibility: of the standard makers, of the practitioners that apply it, of the whole sector of biodegradable plastics. Therefore, the answer to the
question “Is there a need for standards and norms to be modified to take better account of the properties of plastics containing oxo-degradable additives?” is “No, just the opposite.” There is a need for standards and norms that take into account the environment and select plastics that are able to solve the needs of the environment. The Bioplastics Council of The Society of the
Plastics Industry (SPI) in Washington, DC, did not supply information specifically for this feature, but it has recently updated its ‘Position paper on degradable additives. Here are some excerpts:
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NAPCOR says that the use of degradable additives in PET packaging poses a threat to recycling activities
Degradable additives… may cause fragmentation as a result of a chemical oxidation of the plastics’
polymer chains triggered by ultraviolet irradiation or heat exposure, or outright biodegradation of the organic additive. In a second phase, the resulting fragments are claimed to eventually undergo biodegradation. While there is chemical theory to support a very slow biodegradation process, the absence of light and oxygen as well as the presence of moisture or very low temperatures act as dimmer switches for the process, resulting in a very slow or absent chemical process. Degradable additives include stabilizers to limit the
unwanted fragmentation of the polymer chains while the plastic is progressing along the value chain. A peer reviewed research study
has concluded that “even with some content of stabilizing additives, PE film
[with degradable additives] loses its mechanical properties rather
fast, especially when exposed to sunlight”. For this reason, different storage conditions are required in order to prevent premature ageing. Since no peer-reviewed data has been released publicly relating to
mineralization rates that support the claims of complete biodegradation, the term “oxo-biodegradable” lacks meaning and is not supported by any recognized industry certifications or third-party reviewed scientific data.
Plastics recyclers have also expressed concerns about the impact of oxo-degradable additives. The Association of Postconsumer Plastic Recyclers (APR) in Washington DC, USA, reiterated its opposition to degradable additives used in plastic packaging and films in a statement issued in April this year. Steve Alexander, APR’s director, said: “Since mid-2009, APR has repeatedly asked those who sell and those who use oxo-degradable or biodegradable additives to consider the sustainability implications of those additives on the recyclability of packaging. We have asked for the data that support the claims of bottles containing the additives would have no impact on the recyclability of a bottle, including next-use life. We have seen no credible supporting data. Without mitigating data, we must oppose the misuse of such additives in recyclable plastic.” John Standish, APR’s technical director, added: “The
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real concern is the impact of a degradable additive once the plastic is recycled and used in second and succes- sive applications. A great deal of recycled plastic goes into carpeting, geo-textiles, strapping, plastic lumber, and pipe. All are long-lived uses. Some of these products have a 30-plus year expected life span. What happens if the polymer molecules break down during the expected service life? Failure and potentially expensive remediation likely result.” The APR updated its ‘Position statement on degra-
dable additives used in bottles, forms and films’ in April 2013. It states:
40 COMPOUNDING WORLD | August 2013 ‘‘
The degradation of otherwise recycled plastics means lost opportunities for the repeated use of
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