Bio-based plastics have made considerable progress in recent years, with new chemistries and improved formulations expanding the range of applications in which they can compete with conventional polymers.
Yet, an important obstacle to wider adoption lies beyond the material itself: getting it to perform consistently once it leaves the laboratory and enters a commercial production environment.
For Dr Phoebe Heseltine, that distinction is rooted in a decade working with biomaterials and their processing. Her work with polyhydroxyalkanoate (PHA) materials for medical implants demonstrated the potential of a polymer that can be bio-based, biocompatible and biodegradable, while also exposing the difficulties involved in taking promising materials into scalable production.
“It’s essentially a plastic that exists in nature, but we don’t have the means to scale it and deliver it and get it into everyday consumer use,” she tells Eco-plastics in Packaging.
That experience helped shape the thinking behind Natural Negative, the company she created with mechanical engineer Kumar Krishnamoorthy. Having previously worked together, the pair encountered a recurring problem: biomaterials that perform convincingly under development conditions can behave very differently when introduced to production equipment.
Today, the duo are on a quest to help converters find that all-important consistency.
“He and I really started this because we’d worked in industry together previously and had discovered that it’s actually very, very difficult to get bio-based materials to behave consistently in production,” Heseltine explains.
Natural Negative was founded around two years ago and is described as a materials science and materials intelligence company. Its work centres on helping companies transition away from conventional plastics by developing biomaterial formulations that are designed around their products and existing manufacturing processes.
For Heseltine, the difficulty facing bio-based plastics is increasingly one of reproducibility rather than simply discovering materials with suitable properties.
“The materials around us shouldn’t be harmful, and there are better options now than there used to be,” the company’s chief executive notes. “The problem is that bio-based materials behave in a lab and then struggle on a real production line, so they never get used at scale.”
Making bio-based materials work on existing lines
For manufacturers, consistency is, therefore, a fundamental consideration.
“Conventional plastics have decades of tight specifications behind them, so a factory knows what it’s getting; bio-based materials vary far more, batch to batch and supplier to supplier, which means scrap and downtime,” she says.
“For many applications the material is good enough now. The real question is whether a factory can run it reliably on the kit they already have. So, the first job is de-risking the switch and getting it to run consistently.”
Cost remains another barrier, particularly while production volumes are still relatively low.
“The cost is the next thing to tackle: bio-based carries a premium today, and it comes down as we normalise the manufacturing and reach consistency at scale,” Heseltine says.
The difficulty in achieving that consistency is partly rooted in the manufacturing infrastructure itself. Conventional plastics have been processed on established production lines for decades, creating highly optimised systems built around a relatively small number of materials.
“Production lines were tuned over decades for a handful of conventional plastics, down to the temperature settings and the software,” Heseltine explains.
“Bio-based materials flow differently and are more sensitive, so dropped into a line set up for something else they warp or clog and the output varies.”
Why manufacturing has been overlooked
The manufacturing challenge has also received less attention than the development of new materials, she believes.
“As for why – it’s mostly incentives,” Heseltine adds. “Inventing a material is fundable and gets published; getting it to run cleanly on a line at two in the morning doesn’t.
“And the people who develop materials usually aren’t the ones running the factory, so the effort has gone into the material rather than into making it work where it has to.”
For converters, investing in entirely new production equipment simply to accommodate an unproven bio-based material is unlikely to be viable. New machinery requires substantial investment, while emerging materials may initially have uncertain demand and relatively low production volumes.
For Heseltine, the ability to use existing production infrastructure will be critical to taking bio-based materials beyond niche applications.
“It’s essential, at least for the next decade,” she says. “You can’t ask a converter to buy new equipment for a material that isn’t proven and might only run at low volumes – the numbers don’t work. So, the material has to earn its place on the line that’s already there.
“If it only runs on special kit, it stays niche. If it’ll run on standard machinery, the whole existing industry can use it, not just a few specialists.”
From formulation to production
It is this relationship between material formulation and manufacturing that Natural Negative is attempting to address through its software platform DropForm.
DropForm takes a manufacturer’s requirements, including performance, safety and manufacturing method, and generates a production-ready compostable formulation designed for its existing lines and tooling. Natural Negative then supports the manufacturer through trials.
Heseltine describes the approach as fundamentally different from simply developing another material.
“We don’t try to invent new materials,” she says. “We make the ones that already exist behave predictably.
“If you really understand how a particular polymer and its additives perform, you can turn a formulation into something a factory can count on rather than something worked out again every batch.”
The distinction, she says, is between treating material development as a one-off exercise and treating manufacturing consistency as an ongoing data problem.
“That’s what DropForm does,” claims Hesletine. “The difference is how we think about it. Most of the market treats making a material work as a one-off, hand over a recipe and move on. We treat it as a question of data and consistency, so it behaves the same across batches, suppliers and lines.”
DropForm is designed around the customer’s specific product and production line rather than providing an off-the-shelf biomaterial. The customer defines the required performance, safety and manufacturing method, while the platform generates a formulation for those requirements.
Although the company supports customers through production trials, and the resulting formulation is intended to run on existing tooling, manufacturers can choose who produces the material, avoiding supplier lock-in.
The commercial case for bio-based plastics
The technical challenge, however, sits within a broader commercial calculation. Manufacturers considering a transition to bio-based plastics tend to have concerns that must be addressed.
And, as Heseltine explains, the main concerns are always around cost and performance.
“The first question is always whether it costs more than what they use now, and if so whether they can absorb it or pass it on, because margins are thin,” she says.
“The second is whether it performs, shelf-life, barrier, whatever the product needs, at least as well as what it’s replacing. If it performs worse, no sustainability story saves it.”
Consistency, regulation, and supply follow those initial considerations, but there is also a question of where the risk of transition ultimately sits. A brand may commit to a material change in response to sustainability objectives or retailer demands, while the operational risk falls on the people responsible for manufacturing the product.
“The company commits to bio-based for sustainability or because a retailer asked, but it’s the people making the product who carry the risk,” Heseltine notes. “A lot of the work is bridging that.”
Where the industry still falls short
Heseltine sees the wider bioplastics industry against a backdrop of considerable progress. PHAs have become more established, polylactic acid (PLA) has matured, feedstocks have improved and major companies are making commitments that can help drive demand.
“The materials have come a long way. There’s real variety now, PHAs, more mature PLA, better feedstocks, and big companies committing to them, which pulls demand through,” she says. “Recycled content has grown too.”
The remaining gaps, however, are increasingly apparent further down the value chain, “such as reliable manufacturing at scale, proper quality control, and shared standards and data so a converter isn’t starting from scratch each time”, Heseltine explains.
“There’s also the end-of-life question, where the infrastructure to compost or recycle at scale often isn’t there yet.
“The materials have got ahead of the systems around them, and that’s where the work is now.”
Beyond the material itself
The terminology used to describe bio-based materials can itself create confusion. Heseltine identifies the assumption that bio-based means compostable or biodegradable as one of the industry’s most persistent misconceptions.
“The biggest misconception is thinking bio-based means compostable or biodegradable. Those are separate things, and a material can be one without the other,” she says.
“Even the genuinely compostable ones usually need industrial conditions that mostly aren’t in place yet.”
Nor, she argues, should bio-based automatically be treated as synonymous with lower carbon emissions.
“The second is assuming bio-based automatically means lower carbon. Sometimes it does, sometimes it doesn’t, depending on the crop, the energy to process it and what happens afterwards,” Heseltine says.
“The third is closest to what I do. The idea that this is basically a chemistry problem. For a lot of uses it isn’t any more. The material is good enough. The challenge is actually to get materials to work reliably at scale.”
Building confidence across the value chain
That requires a change in emphasis across the entire plastics value chain.
“Everyone has to stop treating this as purely a research problem,” Heseltine says.
“Suppliers need to make their materials more consistent and hand over real data, not just a datasheet. The machinery makers need to give proper guidance for these materials instead of assuming conventional settings will do. Converters need to trial things and share what’s actually happening on the line.
“And the companies putting products on shelf need to be realistic about volumes and willing to pay for the integration work, not just the material. Across all of it we need shared standards, better data and clearer regulation.”
Natural Negative is now working with customers undertaking material transitions, alongside grant-funded projects that are intended to build out its technical capabilities. The company is also expanding its team as it develops its technology and commercial activity.
What comes next for bio-based plastics
The next stage, according to Heseltine, is not about expecting bio-based materials to replace conventional plastics wholesale. Instead, she sees them becoming another established option for manufacturers when the technical, environmental and commercial conditions are right.
“In five to 10 years I’d expect bio-based materials to be a normal, low-risk choice where they make sense; not everywhere, and not replacing all plastics, but used where sustainability, performance and economics line up,” she says.
Achieving that will depend on manufacturers developing the same level of confidence in bio-based materials that they have built up around conventional polymers.
“For that, consistency and quality control have to get good enough that factories trust these materials the way they trust conventional ones, and we need common standards, better data and clearer rules,” Heseltine explains.
“The chemistry is mostly there. The next 10 years are about building everything around it, and that’s the part I find most interesting.”
More information from Natural Negative.
