Sustainable Manufacturing: What bioplastics means for your business
4 minutes | 24 Aug 2021
Bioplastics represent a small share of the total amount of plastic produced, but dynamic year-on-year growth reflects soaring interest from consumers and businesses alike.
Plastic is one of the most widely used materials on the planet, found in everything from packaging and textiles to aircraft and buildings. Plastic is the ideal material for so many applications that the world now produces more than 380 million metric tonnes every year. However, increased environmental awareness, growing concern over plastic waste and stringent new government legislation means the search is on for a more sustainable alternative. Enter bioplastics.
Globally, bioplastics currently account for just 1%-3% of the total amount of plastics produced. The market is set to grow by more than 20% annually between 2021 and 2026. This sustained double-digit growth could see bioplastics accounting for as much as 40% of the total plastics market by 2030.
These numbers reflect the media buzz currently surrounding bioplastics. Anyone attempting to learn more will swiftly encounter a wall of information – currently 3.3 million search results and counting.
The Australasian Bioplastics Association sees a positive future for bioplastics: “In recent years, the face of the plastic industry has begun to change. Numerous biobased plastic materials have been developed and today represent a proven alternative to their conventional counterparts. Most fossil fuel-based plastics could technically be substituted with biobased plastics. As bioplastic technologies and costs of production change, it will increasingly happen."
This guide will cut through the hype and help you to better understand:
- What are bioplastics?
- How are bioplastics made?
- What are the benefits of bioplastics?
- How can bioplastics be disposed of?
- How Essentra Components is helping
- What’s the future for bioplastics?
What are bioplastics?
The term ‘bioplastics’ encompasses a broad family of materials, each made from different raw materials offering distinctive properties, uses and benefits. Broadly, bioplastics fall into three categories:
1. Biodegradable and manufactured entirely / in part from bio-based material
2. Non-biodegradable and manufactured entirely / in part from bio-based material
3. Biodegradable and manufactured using petrochemical-based material
That some of these terms are (mistakenly) used interchangeably adds further confusion. So, let’s start at the beginning and make this easier for you:
A Bio-Based Material is derived from biological matter, i.e. living (or once-living) organisms. It can refer to materials such as wood, leather and wool. However, it’s more commonly used to describe processed materials such as engineered wood (plywood or MDF) or a bio-based plastic.
Bio-Based Plastics (or bioplastics) are manufactured wholly or partially from natural, renewable feedstocks rather than oil. The growing list of renewable feedstocks includes vegetable fats and oils, sugar cane, woodchips, agricultural by-products like corn starch, and microorganisms. Because they contain natural or biological material, many people assume all bioplastics are biodegradable; but that isn’t the case.
Biodegradable Plastics are capable of being completely broken down into smaller and smaller pieces, and eventually natural elements, by microbes. Depending on the surrounding environment, these elements include biomass (compost), carbon dioxide, water and methane.
Not all bioplastics are biodegradable
It’s important to note that while all biodegradable plastics are bioplastics, not all bioplastics are biodegradable. Some are made from a mix of biological and oil-based material.
The biodegradation process depends on specific environmental factors including:
- Presence of particular micro-organisms.
How long it takes ranges from weeks to years. This is what separates biodegradable plastics from compostable plastics. The latter typically takes between 90 and 180 days to fully decompose.
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 break down under home composting conditions, and vice versa.
A relatively new advancement is the development of Oxo-degradable Plastics. These are plastics made from conventional raw materials (petroleum, natural gas or coal), treated with additives causing the plastic to degrade. They are frequently discussed alongside biodegradable and compostable plastics.
But oxo-degradable plastics don’t break down at the molecular or polymer level like the other two. Instead, they fragment into ‘microplastics’ (less than 5mm or 0.2 inches in length). These can remain in, and cause harm to, the environment for up to 450 years, according to the World Economic Forum.
Knowing these terms, and understanding the differences between them, will help you and your customers make more informed buying decisions.
Can’t tell your Circular Economy from your Carbon Footprint? Don’t know the difference between Industrial Composting and Home Composting? Check out our handy Sustainable Manufacturing Glossary.
How are bioplastics made?
The recipe to manufacture plastic, bio or otherwise, largely follows a similar four-step process:
- Extract raw materials, either 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 aren’t typically used in their raw, unprocessed state.
- Refine these materials to convert them into ‘monomers’. In the case of crude oil, these include liquid fuels, lubricants, petrochemicals and naphtha (a crucial ingredient in the manufacture of plastics).
- Polymerisation uses heat and pressure to chemically bond chains of these 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 broken into pellets, ready to be transformed into plastic objects of every size, shape, colour and design imaginable.
The main difference between conventional plastics and bioplastics is what it’s made from, rather than how it’s made.
Polyethylene (PE), for example, is the world’s most commonly used plastic. This lightweight, durable thermoplastic is used to produce everything from food packaging films and bottles, to supermarket bags and bullet-proof vests.
Conventional PE is made from refining crude oil into ethanol, which is then polymerised to produce ethylene. Bio-based PE follows the same process using sugar cane, sugar beet or wheat grain, and performs exactly the same as conventional PE.
Ref: This is Plastics
What are the benefits of bioplastics?
Bioplastics offer a number of benefits over conventional plastics beyond reducing the world’s reliance on fossil fuels.
For example, using materials that are renewable or biodegradable enables manufacturers to diversify their feedstocks. This increases their ability to cope with any supply chain disruptions or price increases. Some natural fibres are low-cost, abundant and don’t produce harmful by-products during processing compared to crude oil.
Bioplastics can weigh less than conventional plastics. This is a particular advantage for industries such as automotive and aerospace where ‘lightweighting’ is becoming increasingly important for fuel efficiency.
Expanding the use of bio-based materials helps avoid sending waste to landfill. Composting and recycling are additional waste management options.
However, the issue isn’t quite as simple as ‘bioplastics = good, conventional plastics = bad’. The world is still highly dependent on oil, with many plastics created from by-products of the oil refining process. What would happen to these petrochemicals should bioplastics become the norm?
Also, the material cost of bioplastics is higher than petrochemical alternatives. This is largely because of low yields, the cost of research and development and building new processing facilities and distribution channels.
The most widely used bioplastics are made from sugars and starches harvested from land that could be used for food. Growing these crops and refining them into useable materials requires land, water and energy – all of which are facing shortages.
To address these concerns, research is underway in labs around the world to identify alternative renewable feedstocks. Frontrunners include algae, which grows on water rather than land, and cellulose, found in abundance within trees, straw and cotton.
Yet the greatest barrier may not come from the start of the lifecycle, but the end.
How can bioplastics be disposed of?
We’ve already mentioned how not all bioplastic is biodegradable or compostable. And, that certain environmental conditions have to be in place for material to break down. These may seem like trivial details. However, disposing of bioplastics incorrectly can cause just as much harm to the environment as conventional plastics.
A ‘compostable’ label, for example, doesn’t mean it goes in your garden compost heap. Many compostable plastics have to be processed at an industrial composting facility. Here material is shredded and turned frequently, and temperatures are far higher and more carefully controlled.
A compostable plastic that finds its way into landfill won’t biodegrade. It needs air, moisture and sunlight to break down properly. Similarly, a bioplastic that enters one of the world’s oceans can still cause the same issues as conventional plastics.
A lack of industrial composting facilities worldwide means the focus has been on recycling. Many bioplastics can be recycled. However, their specification and characteristics determine if they can be mixed or treated separately.
Only certain bioplastics can be recycled together with their oil-based equivalents, such as Polyethylene (PE) and Polyethylene Terephthalate (PET or PETE). Introducing biodegradable or compostable material to an incompatible recycling stream can create problems by potentially comprising the end recycled product.
All this demonstrates the vital importance of raising awareness among businesses and consumers. It shows the need for clear labelling regarding disposal, and improved systems for waste material recovery, sorting and separating.
Ref: European Bioplastics
How Essentra Components is helping
Many believe that recycling represents the best end-of-life option for most bioplastics. As a signatory of the European Commission’s Circular Plastics Alliance, Essentra Components is dedicated to increasing our use of recycled polymer raw materials. Our support will contribute to CPA’s aims to boost the European recycled plastics market to 10 million tonnes by 2025.
We have increased the percentage of post-consumer recycled plastics used in our low-density polyethylene (LDPE) product lines. And, while LDPE is the current focus, our aim is to incorporate more sustainable materials across the product portfolio. By 2025, at least 20% of material processed will be from more sustainable sources.
What’s the future for bioplastics?
Like many environmental concerns, this is a nuanced, complex issue.
Plastic is lightweight, strong, transparent, waterproof, hygienic, and for many applications is the ideal material. That makes it almost impossible to remove the world’s use of it entirely.
Alternatives such as bioplastics have an important role to play. But producing it at the required volume and price-point to drive mainstream adoption will take time.
Still, mounting demand from industries such as electronics, pharmaceutical and transportation means the bioplastics market is likely to increase sharply. The introduction of legislation to minimise the production and consumption of plastic products is also likely to boost the bioplastics market and R&D.
For these reasons, bioplastics aren’t likely to be a short-term trend. Each different option regarding raw materials, their properties and waste management needs considering.