THE GREEN
 FACTS 

Additives added to polyethylene for the express purpose of rendering the polyethylene article as ‘biodegradable’ are controversial. These additive technologies (also known as degradable, oxo-degradable, oxo-biodegradable, photo-degradable, or photo-oxo-degradable) have been around for decades and are based on chemistries that either: 1) promote the oxidative degradation of the polymer in the presence of oxygen and either heat or sunlight; or 2) are composed of materials that are readily biodegradable (e.g. starch or cellulose) that are easily broken down in the environment, leaving the polyethylene largely intact. To the best of our knowledge, neither technology is capable of fully degrading the polymer and relies on the partially degraded plastic article that results from these processes to be subsequently degraded by microbes present in the environment, thus rendering the article ‘biodegradable’.

However, in most cases, the partially degraded polymer fragments are not decomposed to an extent that they can be sufficiently consumed by microbes. The resulting plastic fragments (i.e., microplastics) persist and often lead to other detrimental impacts to the environment, that in some cases, are more worrisome than the original plastic article itself. Furthermore, the use of these additives does not make them compatible with commercial composting and can compromise the mechanical recyclability of the plastic article, meaning that the only viable disposal method is to landfill it. 

NOVA Chemical’s Additives Technology team therefore recommends that any organization considering use of these additives carefully examine the provided technical information and scrutinize the claims of biodegradation, to determine if these claims are aligned with their sustainability objectives. Several notable organizations share similar opinions, and the following are links to relevant webpages discussing the controversy surrounding additive technologies for degradable polyethylene: