Oxo-degradable plastics are made of petroleum-based polymers (usually polyethylene (PE)) that contain additives (usually metal salts), which accelerate their degradation when exposed to heat and/or light. The plastic is fairly common in the market, being used in a range of applications including carrier bags, packaging and agricultural films. They are often marketed as being ‘degradable’, ‘bio-degradable’ or ‘oxo-biodegradable’, implying a reduced environmental impact at the point of disposal compared to plastics without the additive.
Defra commissioned Loughborough University to undertake a research project which assessed the environmental impact of oxo-degradable plastics across the life cycle. The main purpose was to review published literature and engage with key stakeholders to understand what happens to the polymers and metal salts after the material starts to degrade, and to assess whether this has beneficial or negative effect on the environment compared with plastics that do not contain the additive. The project also reviewed evidence behind the marketing claims being made about oxo-degradable plastics, in particular, assessing the evidence that these materials degrade or biodegrade, and under what conditions and timeframe.
The output of the research is a report for Defra detailing the evidence reviewed, the methodology used and any knowledge gaps identified.