Plastic pollution is one of the most pressing environmental issues with around 11 million tonnes of plastic waste ending up in the earth’s oceans every year, according to the Breaking the Plastic Wave report published in October 2020. And plastic production is still speeding up.

“We don’t have any time to waste to address these issues,” said Daniel Schmidt who leads the green polymers research group at List. But going green and doing it sustainably aren’t necessarily the same thing.

“You can make almost any plastic you want from plants. The point is that you may need to spend a ridiculous amount of energy and resources to do so,” Schmidt said, for example using large amounts of water or food crops. And the bio-based plastic’s lifecycle might be shorter than that of conventional plastic.

“If you could imagine a petroleum-based material that’s very readily and repeatedly recyclable or reusable, that could very well be more sustainable than a poorly chosen bio-based process,” the scientist said. 

Tyres and 3D printing

Since 2017, List has been working with manufacturer Goodyear on developing more eco-friendly tyres. “A rubber compound is a very complex mixture,” Schmidt said, that should deliver optimum grip, treadwear and rolling resistance. “It’s about a combination of performance and sustainability.”

Another area of research is using so-called lignocellulosic biomass to make plastic. Derived from wood and the stems of plants, it gives them structure and stability. “A colleague of mine is finding ways to use those materials, chemically modify them or break them down and rebuild them into new plastics,” Schmidt said. “You can find these compounds everywhere in nature, they’re plentiful and often a waste product.”

The waste turned into plastic could for example be used in 3D printing, Schmidt said. “3D printing is becoming a more and more significant means of manufacturing parts, so it makes sense that we look at using more sustainable materials.”

Researchers with a panel made using bio-based resin developed at List (Photo: List) 

Making new materials is, however, only one part of the sustainability equation. “When we design new materials, we have to think about their end of life,” Schmidt said. “We have to do that now, not after we’ve produced 10 million tonnes of the stuff.”

Since the 1950s, factories have produced 8.3 billion tonnes of plastic, according to the UN’s environment agency, with only around 9% of all plastic waste ever produced having been recycled. The strength and resistance that make conventional plastic so useful also mean it can survive for centuries in nature. This is also a problem for things much larger in size than single-use shopping bags or cutlery.

Patent pending

“Wind turbine blades are made of glass fibre and epoxy resin. This gives you very lightweight, very strong material,” said Schmidt, but it also makes the composites difficult to recycle. The US state of Wyoming hosts a graveyard for 1,100 wind turbine blades. Several cities in the Netherlands have used a much smaller number and turned them into adventure playgrounds for children.

In his previous position at the University of Massachusetts Lowell, Schmidt worked on improving recyclability and repairability of wind turbine blades. A colleague in his 10-strong team at LIST is now working on using a more advanced class of bio-based materials for related applications in structural composites while colleagues in another group are developing ways to more quickly and effectively take composite materials apart.

Rather than competing with bigger research institutions, List has tried to find niches where it can make a difference. “You have to look for your areas of strength, which we absolutely have,” Schmidt said.

The first patents to emerge out of the Goodyear collaboration are pending and could be rolled out in the next couple of years, Schmidt said. “We’re always trying to find ways to accelerate,” he said, “to be more efficient, and to develop these things faster.”

After all, “we’re among the very few, a fraction of a percent of the population that are able to do this kind of work,” Schmidt said. “If we choose not to, who’s going to do it? If we don’t act now, when will it happen?”