Project News: Deciphering (bio-based) plastics

It is increasingly common to find plastic-based products labelled as ‘compostable’, ‘biodegradable’, ‘oxo-degradable’ or ‘bio-based’. But what do these words mean? SEALIVE project partner Greenovate! Europe (G!E) is analysing the plastics value chain and developing business plans to support the uptake of bio-based plastic solutions. Part of this work is understanding the challenges faced by consumers when using bio-based products. Here Daniel Lissoni (G!E) explains the different types of plastics and their end-of-life processes.

Our dependency on plastics

Plastics are an increasingly important material in our everyday life. They are versatile, light and often produced at a very low financial cost. The fundamental challenge we face is that currently, only 1% of plastic products on the global market are considered to be bio-based, compostable and/or biodegradable. Decoupling plastic production from fossil feedstock and creating a circular plastics economy are essential to achieving EU climate and sustainability goals. For perspective, every year around 12 million tonnes of plastic waste ends up in our oceans and contaminates our land. While we have noticed in recent years a move towards the use of bio-based plastics, these materials have limitations and are not easy to recycle using current technologies.

SEALIVE is working to address all these challenges with a vision to reduce plastic waste and contamination on land and in seas by boosting the use of biomaterials and contributing to the circular economy with cohesive bio-plastic strategies.

Are there good plastics?

One of the challenges, faced by both our project and other similar ones, is the confusion created around the labelling of plastic products. It is increasingly common to find plastic-based products labelled as ‘compostable’, ‘biodegradable’, ‘oxo-degradable’ or ‘bio-based’. For consumers, these labels create a large degree of confusion, especially when trying to ensure the correct end-of-life processing of discarded plastic products.

Bio-based plastics are fully or partially made from biological resources, rather than fossil raw materials. As noted above, bio-based materials are not easy to recycle and are also not necessarily compostable. The term ‘bio-based’ therefore simply refers to the production process of the product and not its end-of-life treatment.

With regards to ‘biodegradable’ and ‘compostable’ plastics, both products can be manufactured from either bio-based or fossil fuel raw material feedstock. They are also often produced to have similar functionality to or the same functionality as conventional plastics; for example, plastic used in food packaging.

The primary difference between compostable and biodegradable plastics is that compostable products require a specific setting in order to break down, whereas biodegradable plastic may be engineered to biodegrade in soil or water. In order for a plastic to be labeled as commercially “compostable”, it must be able to be broken down by a biological treatment at a commercial or industrial composting facility. Composting utilises microorganisms, heat and humidity in order to yield carbon dioxide, water, inorganic compounds, and biomass that is similar in characteristic to the rest of the finished compost product. Decomposition of the plastic must occur at a rate similar to the other elements of the material being composted (within 6 months) and cannot leave a toxic residue that would adversely impact the ability of the finished compost to support plant growth.

While composting is generally a much faster process than biodegradation, this can only take place under the right conditions. Ultimately both of these kinds of products are better for the environment than fossil fuel-based plastic products that can take hundreds of years to disintegrate.

To add further confusion to the mix, in recent times the term ‘bioplastics’ has also gained usage, referring to plastics that are bio-based and/or biodegradable. Considering that bio-based and biodegradable materials have very different properties, consumers are understandably confused about the ambiguous term ‘bioplastics’.

What to remember

• Biodegradable plastics are designed to biodegrade in a specific medium (water, soil, compost) under certain conditions and in varying periods of time.
• Industrially compostable plastics are designed to biodegrade in the specific conditions of an industrial composting plant or an industrial anaerobic digestion plant with a subsequent composting step.
• Home compostable plastics are designed to biodegrade in the conditions of a well-managed home composter at lower temperature. Most of them also would also biodegrade in industrial composting plant conditions.
• Bio-based plastics are fully or partly made from biological raw materials as opposed to the fossil raw material (oil) used in conventional plastics.
• Non-biodegradable plastics last for long periods of time. They can disintegrate into smaller pieces, forming microplastics, and accumulate in the environment.

SEALIVE is a €10.26 million European Union Horizon 2020-funded Innovation Action project that has the vision to reduce plastic waste and contamination on land and in seas by boosting the use of biomaterials and contributing to the circular economy with cohesive bio-plastic strategies.