Sir David Attenborough’s documentary series Blue Planet II has been credited with igniting what is now a bona-fide revolution in ethical consumption.
Footage of turtles tangled in shopping bags and albatross chicks dining on plastic fragments shocked viewers – and made them realise that synthetic materials have crept into every corner of their lives.
Brands and manufacturers are feeling the pressure to prove their environmental credentials to consumers. And, to get ahead, they’re going to have to rethink what they know about product packaging.
Investors and materials scientists alike are still searching for the holy grail of green plastics – a substance that is truly marine degradable and made from a sustainable plant-based feedstock. Many packaging materials available today are claimed to be biodegradable or compostable, but there’s still some confusion about what these terms signify.
Plastics defined as biodegradable are made of molecules that can degrade in the natural environment. But there doesn’t tend to be a specified timescale for these breakdowns, meaning that a product marketed as environmentally friendly could linger in the ocean for years.
On the other hand, products claimed to be compostable are often subject to greater scrutiny. Compostable plastic certified under the European Standard EN 13432, for instance, must break down under industrial composting conditions in less than 12 weeks. However, industrial composting environments are controlled, with the optimum ratios of heat, moisture and microorganisms. The average landfill or estuary won’t be this perfect – and many recycling schemes can’t take bioplastics.
That being said, there are undeniable environmental plus points for slow-to-degrade bioplastics. Namely, that they’re not made from petrochemicals like most conventional plastics. The production of oil and gas itself releases significant amounts of greenhouse gases, and the process of turning fossil fuels into plastic takes huge quantities of energy. Once plastic is discarded, it’s often burned to make electricity – generating even more emissions. In contrast, plant-based plastics only release the carbon the plants absorbed from the air as they grew.
Researchers at the University of New South Wales in Sydney recently discovered that waste from the banana-growing business could make an ideal feedstock for bioplastics. The team found that pseudostems – the layered trunks of the banana plant which are largely discarded after harvest – can be dried, powdered and processed to create a material with multiple uses in food packaging.
“If the banana industry can come on board, and they say to their farmers or growers that there’s a lot of value in using those pseudostems to make into a powder which you could then sell, that’s a much better option for them as well as for us,” said associate professor Jayashree Arcot. “I think the packaging companies would be more willing to have a go at this material if they knew it was available readily.”
The UK government has also shown interest in turning common waste into sustainable packaging. Last July it launched the Smart Sustainable Plastic Packaging challenge, and an associated £60m funding pot, to develop new forms of packaging made from plants, wood chippings and food scraps. Businesses will be able to access the funding through competitions managed by UK Research and Innovation.
The competition could further accelerate development in the field of ‘smart’ use-by labels, which deteriorate at the same rate as a wrapped item of food. The idea is to deploy technologies (like the much-hyped Internet of Things) to reduce food waste. According to a 2018 study by researchers from the University of Liverpool and the University of Northumbria, the global market for smart packaging could be worth almost $27bn by 2024. Sensor-embedded labels will soon be used to extend the shelf life of products, monitor freshness and display information on product quality.
Enter the Loop
Ultimately, the most radical shift in the packaging sector may not be a new technology or material – but a business model based on reuse. A New Jersey firm called Terracycle has recently pioneered this approach in several pilots across the world to much applause. The company’s Loop programme allows subscribers to buy a variety of common products from well-known brands in specially-designed reusable packaging. When customers are finished with a given product, the packaging is collected, cleaned, refilled and reused – creating what the company calls “a revolutionary circular shopping system”.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.