Barely a day goes by without humanity鈥檚 packaging problem making the headlines. We are all familiar with images showing the way plastic pollutes land, rivers, lakes and even parts of the ocean that have become choked with the debris of modern life.
That raises important questions about how society can tackle the problem. And there are encouraging signs that it can. Just as plastic has become a 21st-century headache, companies such as BASF are coming up with 21st-century solutions that involve reducing the amount of plastic society uses, making it from renewable feedstocks and finding better ways to recycle it into other products.
According to a 2017 study published in the journal Science, over 90 per cent of plastics are not recycled. So finding ways to increase the volume of recycled plastic is an important goal.
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One simple solution is to change the colouring used in some plastics. Ready meals are often sold in black plastic trays. Manufacturers use them because they make food look more colourful and appetising. However, this is a problem for recycling plants, which rely on automated detectors to sort plastics from other recyclable materials.
Unfortunately, the carbon-based pigment in traditional black plastic does not reflect the near-infrared radiation relied on by the sorting machines. BASF鈥檚 Sicopal and Lumogen blacks do, however, and can now be incorporated into these plastics. These colourings are food safe and can withstand heating in both traditional and microwave ovens. And the cost will drop as manufacturing scales.
Another goal is to change the recyclability of packaging. In 2016, the world鈥檚 consumers bought 480 billion plastic bottles: that鈥檚 a million bottles a minute, most of them made of polyethylene terephthalate (PET). It is the primary feedstock for plastic bottles, so it is essential to be able to recycle it.
But the process of recycling tends to make plastic less strong. 鈥淗eat and mechanical stress breaks down the polymer chains and makes the material weaker,鈥� says Tony Heslop, senior sustainability manager at BASF in the UK.
Traditional recycling methods involve shredding plastic bottles, heating the material and forming it into pellets. The broken polymer chains this creates means that recycled PET isn鈥檛 strong enough to be made into more bottles. So fresh PET must be used to satisfy demand for these items.
Even though BASF doesn鈥檛 make PET, it is solving this problem using 鈥渃hain extenders鈥�. These are molecules that attach to the broken polymer chains and stick them back together: a kind of molecular superglue. Depending on the amount of chain extender used, the polymer chains can end up longer than in the original plastic, making it suitable for bottles or even higher-grade applications.
And plastics are also becoming more sustainable. Using clever chemistry, BASF has developed biodegradable, certified compostable , which is partly bio-based. 鈥淏iosourced and compostable materials have two benefits,鈥� Heslop says. 鈥淔irstly, they reduce our dependence on fossil fuels and, secondly, by being compostable, these products make separate organic waste collection easier for consumers.鈥�
Most exciting of all, Heslop believes, is the burgeoning frontier of 鈥渃hemical recycling鈥�, which recycles materials at the molecular scale. 鈥淏ASF first looked at this nearly 30 years ago, but it looks like its time may have come,鈥� he says.
That鈥檚 because it could tackle the problem of the 10 percent of plastic waste that is proving extremely difficult to recycle. This is the packaging made of mixed materials, or of multiple layers, or smeared with food it once contained, which creates an almost insurmountable barrier to recycling. But BASF think they might now have cracked the problem (see 鈥�Cluster power鈥�).
Packaging is clearly an important part of industrial society. But BASF engineers believe that their various approaches to the plastic packaging problem have the potential to change its environmental impact. One day soon, we might have our cake and eat it too 鈥� and use its packaging for something new.
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Cluster power
BASF uses the word Verbund to describe its philosophy of minimal waste and maximal efficiency. Verbund literally means 鈥渃luster鈥� and it originally applied to BASF鈥檚 chemical plants, which the company built close together, in such a way that the waste heat from one process could be harnessed for use by different part of the firm鈥檚 infrastructure. Verbund also meant BASF could use one plant鈥檚 by-product as feedstock for another without incurring significant transport costs.
Now BASF is applying Verbund to a much bigger challenge: bringing the 鈥渃ircular economy鈥� into being, where reuse, repair, recycling and remanufacture significantly reduce the resources required to power 21st-century life.
It鈥檚 a vision that the Ellen MacArthur Foundation has crystallised as its 鈥淐ircular Economy 100鈥� programme. BASF is a member of this programme, which aims to allow businesses and other organisations to work closely together to build a fully circular economy.
A key innovation here is BASF鈥檚 chemical recycling process. Reprocessed mixed plastic waste can be fed into a steam cracker that breaks down raw materials, such as naphtha or pyrolysis oil, mainly into ethylene and propylene. These chemicals are used in the Verbund to make numerous products.
鈥淔rom these basic chemicals, we can produce any kind of new chemical products, especially plastics,鈥� says Andreas Kicherer, a member of BASF鈥檚 Global Sustainability team.
It鈥檚 not straightforward to get the chemistry and all the other necessary processes right 鈥� and that鈥檚 why it has taken so long to come good. However, BASF鈥檚 chemical recycling project is now working with customers to produce prototype products with chemically recycled material from plastic waste, which will be an important component of a sustainable future.
This article appeared in print under the headline 鈥淢aking plastic fantastic again鈥�
