Plastics have a bad reputation. Not only do they use 5 per cent of the world’s petroleum in their manufacture, but they’re hard to recycle and aren’t bio-degradable.
What is more, they can also pollute the natural world for centuries, as the BBC’s groundbreaking nature programme Blue Planet 2 has dramatically shown.
It wasn’t always this way. The first plastics from the mid-1800s – like parkesine (“synthetic ivory”) used to make combs, chess pieces and dentures – were derived not from precious fossil fuels but from sustainable materials.
Parkesine’s main ingredient was a liquid solution of nitrocellulose obtained by distilling wood, while casein was derived from milk. In the second half of the 20th century, however, these materials were replaced with cheap and easily moulded oil-derived plastics developed during World War II.
Now, with environmental concerns high on the agenda and the latest technological and scientific discoveries closing the natural versus man-made plastic price gap, many in the industry are turning full-circle. Production of sustainable bioplastics is forecast to increase from 4.2 million tonnes in 2016 to some 6.1 million tonnes in 2021, according to a European Bioplastics report.
The challenge of biodegradability
One early-adopter has been Coca-Cola. In 2009 the multinational drinks corporation unveiled its PlantBottle – the first recyclable polyethylene terephthalate (PET) plastic bottle made partially (30 per cent) from plants. Now, not only are around a third of Coke bottles in North America PlantBottles, but the technology has improved to the point that PlantBottles can now be made entirely from plants. The same process is also used in Heinz Ketchup bottles and Ford hybrid-car interiors.
These bottles may not be biodegradable, but they are easy to recycle. The same cannot be said of traditional plastic shopping bags, cutlery and packaging, which all end up in landfills and oceans. They must be made biodegradable if the plastics industry is to become sustainable.
Biodegradable bioplastics, such as dissolvable sutures, do exist and have been used in niche markets for years. Yet their more general adoption has been hampered because they cannot replace all the properties of traditional plastics or, if they can, they are not cost-competitive. “The cost of bioplastics from renewable sources is in general between two and four times higher than traditional petrol-based plastics,” explains Miguel Alborch, an R&D engineer from the AINIA technology centre in Spain.
Some of that price gap is being breached by the latest technologies and by the economies of scale possible at new biorefineries – where biomass is converted to useful biofuels and biochemicals.
Bio-on is one bioplastics company which is building such a plant near Bologna, in Italy, to make its MINERV-PHA biopolymers for use in a variety of products, from toys and furniture to biomedical and automotive applications. “As raw materials we can use the by-products of sugar beet and sugar cane production, glycerol (biodiesel waste), potato processing waste co-products and many others,” explains company president Marco Astorri.
MINERV-PHAs decompose completely and naturally if left in river water or soil just like wood. Once it is completed in 2018, Bio-on’s new plant will produce 1,000 tonnes of the biopolymers a year, with capacity to double this.
Another bioplastics producer is Novamot, whose MATER-BI bioplastics combine petrol-based or renewable agriculture-based compostable polymers with starch to obtain mechanically strong structures for packaging, carrier bags, plastic cutlery and other applications. “The performance is equivalent to traditional plastics, and we get very fast product biodegradation,” says the company’s business development director Stefano Facco.
Novamot’s shopping bags – which are only slightly more expensive than traditional ones – are used worldwide by numerous retail chains, among them by the UK’s Cooperative supermarkets, and its packaging by Aethic’s skin care products.
New package for cheese
Other groups are exploring different routes to biodegradable bioplastics. For example, the EU LIFE+ WHEYPACK project aims to use a microbial whey fermentation bioprocess, which is created during cheese production, to make a biodegradable packaging material for dairy products.
Turning bio waste – be it from cheese-making or other industries – into plastic would in fact solve two problems : reduce the pollution caused by bio waste and make plastic more sustainable.
“Just in Europe, an estimated 75 million tonnes of whey are produced by cheesemakers every year, of which about 40 per cent is discarded and managed as waste in the food industries,” says project coordinator Miguel Alborch.
“WHEYPACK is a circular project: the generator of the waste – the cheese industry – can make a profit by exploiting the whey surplus to obtain a 100 per cent biodegradable package for cheeses, designed and tailored to the needs of their product.”
With such progress, could the end be in sight for traditional plastics?
