Banana agri-waste converted into biodegradable, recyclable plastic
Even though all plants are a possible source of nanocellulose, banana plants' high cellulose content makes them mostly well-suited – together with the fact that new plants are grown each year
The bunches of bananas commonly available in stores grow off of a central trunk-like structure, identified as the pseudostem. And though that part of the plant is usually thrown away during harvesting, it may shortly find use in a plastic that biodegrades and is completely recyclable.
As reported by Australia’s University of New South Wales (UNSW), the growing of bananas is a mainly wasteful form of agriculture, with just 12 percent of the plant really being used. The pseudostem makes up much of the remaining, and while it can be used in the production of textiles or composted, it’s usually just discarded.
With the intention of bringing new worth to that waste, a UNSW team headed by Assoc. Prof. Jayashree Arcot and Prof. Martina Stenzel developed an experimental new recycling process.
It begins with the pseudostem being cut up into pieces, those pieces then being dehydrated in an oven at a low temperature, and then crushed into a fine powder. That powder is then washed by a soft chemical treatment. This step separates a material called nanocellulose – which is made up of small cellulose fibers – from the rest of the powder. The sheets of plastic are then made from nanocellulose.
A sample of the banana-nanocellulose plastic
The finished product has a texture not unlike that of the parchment paper used in baking, and could possibly be used in products such as food packaging and shopping bags. It can be completely recycled up to three times without any harm in quality, and when it is thrown away and buried in the soil, it decomposes organically. Moreover, lab tests show that the material doesn’t trickle any harmful compounds into food.
The scientists are now looking for industry partners who are interested in scaling the procedure up to commercial production levels, and making it as profitable as possible.