Oxo-degradable

Oxo-degradable is a term used to describe plastic polymers that, via an oxidative process, are more easily degradable into smaller pieces, although those pieces may not necessarily degrade further at the same rate, in effect becoming microplastics, which have a series of associated issues. Oxo-biodegradable infers the potential for further biodegradation but the definition is not clear or standardised.

The European Committee for Standardization (CEN, for Comité Européen de Normalisation) has established the following definitions, in TR 15351:[7]

Oxo-degradation is degradation resulting from "oxidative cleavage of macromolecules";
Oxo-biodegradation is "degradation resulting from oxidative and cell-mediated phenomena, either simultaneously or successively".

These plastics, such as polyethylene (PE), polypropylene (PP), or polystyrene (PS) contain an additive prodegradant catalyst, salt of manganese or iron, that can help in breaking the material down into smaller pieces.

Oxo-degradables are a category unto themselves, they maybe confused with, but are not biodegradable plastics. As they are neither a bioplastic nor a biodegradable plastic, but more accurately plastic mixed with an additive in order to imitate biodegredation. They break down into microplastics, but not to the molecular or polymer level in the same way as biodegradable and compostable plastics. The resulting microplastics left in the environment have increasingly been found to be problematic.