Oxo-degradable plastic looked like it was going to solve our plastic problem. All it takes for an oxo-degradable single-use bag to degrade is oxygen. No longer would plastic waste be floating in the ocean or filling up landfill – instead it would disappear within a matter of months. It seemed like the ideal solution.
Saudia Arabia even introduced a law in 2017 banning all single-use plastic bags not made from oxo material. Then the Ellen MacArthur Foundation published a report finding that oxo-degradable plastics don’t simply disappear. They break down into microplastics, which are then released into the environment – just like normal plastic
Seaweed, fish and plant matter have all been touted as materials that could solve our big plastic problem. But none of these wonder-solutions have quite come to pass, and plastic still remains the principal material used for single use bags, bottles and packaging. By 2050, there will be more plastic in the ocean than fish by weight. If we have the technology to create alternatives, why aren’t we using it?
Part of the problem is that plastic comes in so many varieties – when we talk about getting rid of plastic altogether what we really mean is switching from a huge range of materials that each have distinctive benefits. Polyethylene terephthalate (PET) is strong, clear and lightweight making it ideal for water bottles. Polyvinyl chloride (PVC) is rigid and used for pipes as it requires little maintenance. Polythene is flexible so is used for plastic bags. None of these common plastics biodegrade by themselves, which can be good for preserving food or for long-term use, but means that they collect in landfills, or worse, the ocean.
The search for a substitute is on. Any material looking to replace plastic would need to fulfil certain criteria: most importantly it would need to break down into substances that don’t harm the environment and it would need to be cheap and easy to make and be suited to a variety of situations. While it should biodegrade, it needs to be as strong as its counterparts in order so it's still useful as packaging for food and drink.
While plastic is generally made from fossil fuels such as oil, natural gas, or coal, most biodegradable plastics come from either plants or animal products. These allow alternatives to be more sustainable and could be a way to sequester carbon to help stop the climate crisis.
In 2010, polylactic acid (PLA) was the most used bioplastic in the world. It was touted as biodegradable, and as it’s made from fermented corn starch, it seems more green than regular plastics. It is transparent and strong, making it particularly useful for cups, straws and takeaway containers.
“Everybody started switching to these compostable products, like corn cups because they were told that they were better for the environment,” says Bill Levey, founder of Naeco, a company that creates alternatives to single-use plastics.
It takes 12 weeks for PLA packaging to break down, which meets the EU standard for compostability. This would be ideal if this could happen in the ocean or at home but PLA needs industrial-scale composting conditions – where heat and oxygen is used to break apart the molecule's bonds – in order to break down. If PLA products are thrown away incorrectly, they could take as long to degrade as normal plastic – a 2017 study by the University of Bayreuth in Germany found that in 25C seawater, PLA showed no signs of degrading after a year.
“Ultimately when that product isn't composted it's not necessarily better,” says Levey. “I think we've gotten so used to this idea of convenience and disposable culture. It’s dangerous to think that there is a perfect solution.”
A better alternative could be seaweed. It can grow up to three metres per day, is easy to harvest and grows all over the world. Agar is extracted from the seaweed, creating a sturdy material that can biodegrade in four to six weeks. Evoware, an Indonesia-based startup say it can create tea bags that dissolve in boiling water, soap packets that disappear without even unwrapping it and disposable cups you can simply eat after use.
But seaweed comes with its own problems. To produce enough to fuel a whole plastic-substitute operation, you would need to start up seaweed farms, which environmentalists say bring their own problems. As the farms are in the ocean, there is a risk that the gear could break loose and become entangled with whales and turtles. It is uncertain how large-scale farming will affect the environment, but experts predict that it could bring disease and alter the chemistry of the ocean.
Fish skin and scales could offer an easier route out of our plastic quagmire. MarinaTex is strong, translucent and flexible, and also could help to reduce waste in the fishing industry. Its creator, Lucy Hughes isn’t a scientist or part of a big company trying to create a new material – she is a product design graduate who made the material in her own kitchen for a university project.
“I definitely think there's always a little bit of resistance to change anyway,” says Hughes. She was given the fish waste by a local fish processing plant, and decided to use algae as a binder to keep with the sea theme. But sustainable plastic alternatives won’t become widely used unless the big players in the industry start investing in them. “The initial cost is going to be higher because you haven't got those huge supply chains and those existing refined processes,” she says.
MarinaTex could be available on a small scale now, but Hughes wants the material to have the best impact. More tests must be done before the best application of the material is found.
“It will just take time for alternatives to find their way into mainstream years because they've got to be proven to do the job that the conventional plastics do,” says Barry Turner, a director at British Plastics Federation, a plastics trade association. “In addition, they've got to pass those same regulatory hurdles to make sure that they are absolutely safe to use.”
It might be a while before a commercially viable plastic alternative is found. It’s only over the last decade that this problem has been in the public eye – the 5p plastic bag charge came into effect in 2015, and some of the biggest plastic straw ban campaigns only happened in 2018, in the wake of the the TV series Blue Planet II which increased public awareness of plastic pollution.
To really have a big impact, the ideal plastic solution must work not just for the UK, but also developing countries where plastic pollution is at its worst. At the moment in countries like Indonesia, which ranks second behind China for polluting the ocean, change is happening from the ground up with companies like Evoware, but more government intervention may be required. The Ellen MacArthur Foundation have written an open letter calling on businesses and governments to innovate, so all plastic is designed to be safely reused, recycled, or composted.
Still, there is positive progress being made and we should be seeing plastic alternatives like MarinaTex being used in the near future. “Users are becoming far more aware than ever before,” adds Turner. “I really do see a strong future for the materials derived from renewable sources, from waste products and things like that.”
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