Understanding Plastic Degradation
Gradual but Persistent Fragmentation
Plastic never really disappears, but breaks down into micro and then nanoparticles over very long time scales. This physical (and/or chemical) degradation depends on many factors, such as light, water, heat or micro-organisms.
Degradation is not synonymous with biodegradability: most plastics remain pollutants even after fragmentation. According to UNEP, almost 11 million tonnes of plastic enter aquatic environments every year.
Why Should Manufacturers be Concerned?
Manufacturers are at the heart of the production chain and must anticipate regulatory changes concerning single-use plastics. The European SUP directive, and others, will mean the end of many non-recyclable plastic items in the next few years. Understanding the environmental lifespan of each material helps to limit the ecological footprint of the products we design and distribute.
Breakdown Time by Type of Plastic
- Polyethylene terephthalate (PET) bottles are designed to be robust, but they take up to 450 years to decompose. Yet they are very common: every minute, 1 million plastic bottles are sold around the world. Despite their recycling potential, many bottles escape industrial channels because they are scattered or contaminated.
- A standard plastic bag can take between 20 and 1,000 years to break up, depending on the location and conditions of degradation. Lightweight and mobile, bags are often blown away by the wind and end up in the oceans, where they trap marine fauna. They are one of the top 10 items of litter collected on European beaches every year.
- Plastic straws, cotton buds and cutlery are disposable items that last for centuries in nature. In 2017, an estimated 8.3 billion straws were washed up on beaches around the world. Their small size makes them difficult to collect and recycling them is often technically impossible.
- Fishing nets – often made of nylon or polyethylene – can remain intact at sea for more than 600 years. Abandoned, they become ‘ghost nets’, trapping fish, turtles and cetaceans for generations.
Factors Influencing Plastic Degradation
The Role of UV and Oxygen
Exposure to ultraviolet radiation breaks up polymer chains in a process known as photo-oxidation. The presence of oxygen activates chemical degradation, accelerating the disintegration into ever smaller pieces. However, without light, these plastics can remain stable for hundreds of years, particularly in buried environments.
Influence of Temperature and Humidity
High temperatures encourage thermal decomposition, especially in industrial composters for biodegradable plastics. Humidity, on the other hand, facilitates bacterial activity, which accelerates the biodegradation of certain certified compostable materials.
Nota Bene: In cold oceans, or at great depths, plastic takes much longer to disintegrate.
Land and Sea: Two Different Dynamics
- At sea, plastic is subjected to the mechanical action of waves, salt, UV rays and biodegradation by microorganisms.
- On land, the conditions of burial, aeration and soil pH considerably modify the rate of degradation.
Ecological and Health Consequences
Formation of Microplastics
The fragmentation of plastic forms particles smaller than 5 mm – known as microplastics – which are now ubiquitous in all natural environments. These particles absorb persistent pollutants such as PCBs and pesticides, and become toxic vectors for living organisms.
Bioaccumulation and Risks for Humans
Microplastics travel up the food chain, ending up in the fish, shellfish and seafood we eat. Some plastic additives are suspected of being endocrine disruptors and even carcinogens for humans.
Innovating Through Substitution and Eco-Design
Manufacturers must include compostable, recyclable and/or bio-sourced materials in their product catalogues. Standards such as EN 13432 or ASTM D6400 guarantee compostability under industrial conditions (AFNOR). Finally, eco-design also promotes reparability, re-use and responsible end-of-life for plastic products.
Bioplastics: Why put your Trust in PHA Sourcing?
PHA Sourcing can help you make the transition to alternative, high-performance and environmentally-friendly plastics. We offer PHA-based products derived from natural fermentation, adapted to industrial constraints on a large scale.
PHA is 100% biobased and 100% biodegradable, leaving no toxic residue.
Our teams provide complete technical expertise, from the choice of PHA pellets to their integration into your production processes. We work with certified laboratories and suppliers to guarantee traceability, compliance and efficiency.
With PHA Sourcing, you can anticipate regulatory changes, reduce your plastic footprint and strengthen your brand image.
