Guide to bioplastics: Definition, uses and advantages
Plastic is one of the most widely used materials on the planet, found in everything from packaging and textiles to aircraft and buildings. Using more sustainable ingredients, such as bioplastics, to make polymers could have a positive impact on an OEM’s sustainability goals and create less waste at end of a product’s life.
At Essentra, we are testing both recycled content and various bio-based materials including bio-woods, nylon and Polylactic Acids (PLA) to see how they perform when replacing or added to existing resins used in the manufacture of our plastic components.
What are some of the challenges that plastic creates and bioplastic solves?
Around 400 million tonnes of plastic pollution ends up in the natural environment every year. Many of these polymers are made from fossil fuels such as petrol or oil. Growing concern over the environmental impact this is making means manufacturers are looking for a more sustainable alternative. That's where bioplastics come in.
As European Bioplastics, a trade body that represents the industry, explains, “For almost every conventional plastic material and application there is a bioplastics alternative available on the market." The body also notes that in 2022, 2.22 million tonnes of bioplastics are already being created to replace standard petroleum-based plastics.
In the meantime, manufacturers need to adapt their use of plastic to make it more sustainable. For Essentra, this has included:
- We've introduced over 50% recycled content in many of our LDPE & PP ranges
- We established a baseline for Scope 3 emissions which includes emissions from the materials we use and are developing our Scope 3 science-based target
- We have reduced the amount of waste we generate through resue and recycling. In 2022, our waste intensity reduced 25% against 2019 baseline.
Our commitment:
- Using 50% recycled content in our packaging materials by 2030
- We're dedicated to supporting a circular economy by ensuring 100% of our packaging is reusable, recyclable or compostable by 2030
- We're staying committed to setting science-based targets for emissions reduction, targeting net zero in our direct operations by 2040, and in our supply chain by 2050
- We are targeting all of our sites to achieve zero waste to landfill by 2030 at the latest.
By taking these steps and investing in the research and development of new bioplastics, Essentra is helping its customers reduce their environmental impact with quality, sustainably sourced products and hassle-free service.
What are bioplastics?
Bioplastics are a family of materials made from bio-based sources or biodegradable materials. In some cases, a bioplastic may be both bio-based and biodegradable.
Substances used to manufacture bioplastics include vegetable fats and oils, sugar cane, woodchips and agricultural by-products like corn starch. Due to their natural 'biological' sources, these polymers are referred to as bio-based plastics.
Biodegradable plastic is a polymer that can be completely broken down into natural substances (such as biomass, carbon dioxide, water and methane) by biological organisms like microbes.
Types of bioplastic
There are lots of different types of bioplastics with various characteristics and uses. However, to be considered a bioplastic, a polymer has to meet one or both of the following criteria:
- Being made from renewable, naturally sourced raw materials
- Being biodegradable in the natural environment without causing damage or pollution
This means a polymer made from oil that's biodegradable also counts as a type of bioplastic. So just because a polymer is a bioplastic doesn't mean it has zero environmental impact. Indeed, there are some polymers that don't fit bioplastic criteria but generate less waste and carbon footprint than traditional plastics.
Compostable plastics break down only under carefully controlled conditions using industrial composters or home composting. Materials designed to safely break down in industrial composters may not do so under home composting conditions, and vice versa.
Oxo-degradable plastics are made from fossil fuels enhanced with additives that help the plastic to degrade more quickly than standard polymers. However, oxo-degradable plastics don't break down completely like the other two. Instead, they fragment into ‘microplastics' which are pieces of less than 5mm or 0.2 inches in length. These pieces can still cause significant environmental damage.
Understanding these different terms will help you to know exactly the type of plastic you're purchasing or using.
What are the raw materials for bioplastics?
Bioplastics are made differently depending on whether they're bio-based, biodegradable or a combination of the two. This is because they are made from different source materials. Though each bioplastic will require some form of polymerisation, the way each of the materials is extracted from its source will be different.
For example, traditional plastic polyethylene (PE) is a lightweight, durable thermoplastic used to produce everything from plastic bottles and containers to screws and sockets, which are produced by Essentra, globally. Conventional PE is made from refining crude oil into ethanol, which is then polymerised to produce ethylene. Bio-based PE has the same properties and is manufactured using the same process but is sourced from sugar cane, sugar beet or wheat grain.
The typical bioplastic manufacturing process takes the following steps:
- Extracting raw materials. Either from a renewable feedstock such as plant starch and sugar cane, or non-renewable such as crude oil. These materials are a complex mix of many different compounds. As such, they can't be polymerised in their raw, unprocessed state
- Refining these materials to break down their chemical structure into ‘monomers'. In the case of crude oil, these include liquid fuels, lubricants, petrochemicals and naphtha (a crucial ingredient in the manufacture of plastics)
- Polymerising these monomers using heat and pressure. This chemically bonds chains of monomers together to create synthetic ‘polymers'. Different catalysts are added to create polymers with varying properties and applications
- The final step is to mechanically extrude this molten mixture, usually in a long tube. It is cooled and broken into pellets or sheets ready to be remanufactured into its final product.
At Essentra, we have set up a research and development Centre of Excellence. Included in its work will be testing and trialling of new bio-polymers, which will widen range of materials that can be used in components, ensuring they have the same qualities and capabilities of oil-based parts. It will also be able to provide data on ‘end of life’ of products, how the materials can be re-used or recycled or will break down and become compostable.
What are the advantages of bioplastics?
The main advantage of bioplastics is their reduced impact on the environment. However, there are a few specific benefits that are increasing the popularity of these polymers.
They use diverse feedstocks
The development of bioplastic production technology means an increasing range of organic materials can now be used to make polymers. This reduces the reliance of the plastics industry on crude oil and enables manufacturers to diversify their feedstocks. For example, they can start to develop polymers from crops such as sugar cane, soy and grains.
This increases their ability to cope with any supply chain disruptions or price increases, as they can call upon multiple sources of raw materials. Plus, many of these natural materials are lower in cost, more renewable and don't produce harmful by-products during processing compared to crude oil.
In some cases, it may be possible for industries to divert their waste materials, such as biomass or food waste, into the creation of new bioplastics. This helps plastics manufacturers to improve their sustainability even further.
They have lots of uses
Bioplastic has been developed to have similar properties to traditional plastics. There are several types of polymers that have identical characteristics to existing plastics but are created from biobased sources, such as polyamides (PA) made from natural fats and oils.
As a result, bioplastics can be used for the same applications and turned into products through standard manufacturing processes such as injection moulding.
Figures from European Bioplastics set out the global production capacity of these polymers and the markets they're being used for, including:
- Flexible packaging (695,600 tonnes)
- Rigid packaging (376,100 tonnes)
- Fibres (328,900 tonnes)
- Consumer goods (312,400 tonnes)
- Automotive and transport (159,000 tonnes)
This shows how customer demand and the development of bioplastics with desirable characteristics are already driving the use of these polymers for a range of products, from food packaging to car parts. Plus, as bioplastic production technology develops, the number of applications these polymers can be used for will only increase.
They have some environmental benefits compared to standard oil-based plastics
This is the key advantage of bioplastics for the polymer industry and manufacturers. These are some of the ways that bio-based or biodegradable plastics can reduce the environmental impact of products compared to standard oil-based plastics.
- Less reliance on non-renewable resources like crude oil due to bioplastics' use of organic feedstocks. This reduces the amount of fuel that needs to be extracted, leading to a decrease in the environmental damage associated with this process
- A lower carbon footprint over their lifetime. This is because they use renewable raw materials and have polymerisation processes that release less greenhouse gas emissions than those of standard plastics
- Less plastic pollution, as bio-based and biodegradable plastics can be recycled and composted rather than sent to landfill. Plus, these polymers break down into safe, natural substances like water and biomass meaning they cause less water and soil pollution.
What are the disadvantages of bioplastics?
Though bioplastics can bring huge benefits to the plastics industry and the wider environment, there are some drawbacks they're facing in introducing these types of polymers.
They can cost more
Bioplastics production is still an area of development within the plastics industry. Alongside the science behind the plastics themselves, the infrastructure that supports their sourcing, processing and end-of-life disposal is still being built.
For example, research is still going into the types of organic materials that can be used to create bio-based polymers. Once these are in place, a supplier for these source materials will need to be found and a method for disposal developed.
This means bioplastics can be more expensive to produce than standard polymers. However, as the systems that support the production of bioplastics are put in place and these polymers are more widely used, these costs will start to reduce.
Their use of natural resources
Many bioplastics are sourced from crops such as sugar cane, beets and potatoes. Growing these crops and refining them into useable materials requires the use of vital resources such as water, energy and land.
By 2027, European Bioplastics estimates that 2.9 million hectares of land will be used for bioplastic crops. This level of farming will require the use of environmentally damaging pesticides and fertilisers. It will also throw up ethical decisions around using crops for polymer creation, rather than food production.
As a result, identifying less impactful renewable feedstocks, such as algae and cellulose, has become the focus of polymer researchers.
Their end-of-life disposal
Compared to standard polymers, bioplastics are designed for easier disposal via recycling, composting or biodegrading. However, disposing of bioplastics incorrectly can generate as much plastic pollution as the use of conventional plastics.
For example, some compostable or biodegradable plastics can't be processed at home. This plastic waste must be sent to an industrial facility for the material to be broken down under very specific conditions. Similarly, some bioplastics can't be recycled alongside oil-based polymers. This means separate treatment facilities need to be built to process bio-based plastic waste.
Without these processing infrastructures in place, the end-of-life disposal of bioplastics could be just as damaging as that of standard polymers. As a result, it's key that the right systems, such as clear labelling and effective waste recovery, are put in place.
Ref: European Bioplastics
What's the future for bioplastics?
Bioplastics have an important role to play in reducing the negative impact of plastics on the environment. However, lots of work still needs to be done to develop these types of polymers and their supporting infrastructure. This is essential for bioplastics to be produced at a volume and cost that will make them viable for manufacturers to use.
If you are looking for data around the sustainability of the components you need, Essentra will be able to provide this, from its Centre of Excellence research work. This will include ‘end of life’ information such as how materials will be break down and become compostable and the potential for re-use and recycling.