Compostable transparency: Lithuanian scientists develop see-through bioplastic for food applications

20 Jun 2019 --- Scientists at Kaunas University of Technology (KTU) in Lithuania have created a transparent, biodegradable plastic which decays in a compost bin within a couple of years. The bioplastic is made from cellulose – the most common biopolymer found in nature which is usually derived from timber – and suitable for contact with food.

According to researchers, the main challenge was to create a bioplastic that is degradable but also transparent – a quality necessary for use in applications such as sandwich packs.

“We are used to getting sandwiches, snacks, pastries, sweets and many other products in a paper bag with a plastic window. With a clear window on the front face, the products in the bag can be viewed easily. Although paper is biologically degradable, it is complicated to separate paper from plastic, and the package is considered non-recyclable and non-compostable,” explains Dr. Paulius Pavelas Danilovas, the Lead Researcher on the project.

“However, if we made the window from biodegradable plastic, it could be composted. Moreover, we could even use the bag for collecting biodegradable waste and put it all into the compost bin together,” Danilovas adds.Dr. Paulius Pavelas Danilovas, Lead Researcher.

He admits that being environmentally-friendly has its cost – KTU's bioplastic is several times more expensive than common plastics. However, the growing number of eco-conscious consumers is encouraging industries to take an interest in biodegradable packaging alternatives regardless of higher costs.

The scientists at KTU believe that their bioplastic packaging can help facilitate positive environmental change by replacing difficult-to-recycle, single-use plastics. The European Parliament recently approved a law banning a wide-range of single-use plastic items, including straws, cotton buds and cutlery by 2021. Meanwhile, numerous legislations around the world are being passed in order to control growing levels of plastic waste.

The disintegration process of common plastics takes from several hundred to a thousand years; during that time, the plastic is disintegrating into microplastic particles, which enter the ground waters and find their way into our food and environment. Only nine percent of global plastic packaging is recycled and the rest is slowly degrading in landfills, the scientists point out.KTU's bioplastic is made from cellulose, which is usually derived from timber.

Usually, to become fluid, plastic needs to be heated. However, if you heat paper – which is also based on cellulose – it will not only not become liquid, it will also burn, Danilovas notes. “We are excited to have found composites, which not only allow cellulose to turn into fluid condition, but that are also non-toxic – a quality that is essential for all products related to food handling,” he says.

Danilovas confirms that the microorganisms found in compost digest KTU’s bioplastic effectively. Compostability is a characteristic of a product that allows it to biodegrade in specific conditions under the influence of microorganisms.

According to EU standards, in industrial compost centers, which sustain the temperature of 580°, bioplastic degrades in half a year. However, in a compost bin at home, the process would take a couple of years.