Researchers at the University of Copenhagen have developed a biodegradable plastic from barley starch blended with fibre from sugar beet waste.

The new material, which decomposes in nature in just two months, can be used for food packaging and other things.

The material also reduces the climate footprint of plastic production. “We have an enormous problem with our plastic waste that recycling seems incapable of solving,” says Professor Andreas Blennow of the Department of Plant and Environmental Sciences, University of Copenhagen. 

The researchers' plastic film made from barley starch. Image: Andreas Blennow.

New type of bioplastic that is stronger

The scientists have created a new bioplastic that is more robust and resistant to water than existing types.

“We’ve developed a new type of bioplastic that is stronger and can better withstand water than current bioplastics. At the same time, our material is 100%  biodegradable and can be converted into compost by microorganisms if it ends up somewhere other than a bin,” says Prof Blennow.

Researchers have maintained that only 9% of plastic waste is recycled worldwide, while the rest is either incinerated or dumped into landfills.

Prof Blennow also claims that bioplastics already exist, but they aren’t 100% degradable. Only a limited part of them is degradable under special conditions in industrial composting plants.

He stresses that using bioplastic terms for such material is actually misleading.

“I don’t find the name suitable because the most common types of bioplastics don’t break down that easily if tossed into nature,” he says.

“The process can take many years and some of it continues to pollute as microplastic. Specialised facilities are needed to break down bioplastics. And even then, a very limited part of them can be recycled, with the rest ending up as waste.” 

Main ingredients are amylose and cellulose

The new material is so-called biocomposite and its main ingredients are, amylose and cellulose, which are common across the plant kingdom.

Researchers developed a new type of barley variety that produces pure amylose in its kernels. Notably, pure amylose is far less likely to turn into a paste when it interacts with water compared to regular starch.

Cellulose is a carbohydrate found in all plants and we know it from cotton and linen fibres, as well as from wood and paper products. The cellulose used by the researchers is a so-called nanocellulose made from local sugar industry waste. And these nanocellulose fibres, which are 1,000 times smaller than the fibres of linen and cotton, are what contribute to the material’s mechanical strength, reports

Durable, flexible material could be used for shopping bags

Prof Blennow also highlights that amylose and cellulose form long, strong molecular chains. 

“Combining them has allowed us to create a durable, flexible material that has the potential to be used for shopping bags and the packaging of goods that we now wrap in plastic.”

Researchers maintain that the new biomaterial is produced by either dissolving the raw materials in water and mixing them together or by heating them under pressure. By doing so, small 'pellets' or chips are created that can then be processed and compressed into a desired form.

Prof Blennow claims that his team is quite close to the point where they can really start producing prototypes in collaboration with companies.

“I think it’s realistic that different prototypes in soft and hard packaging, such as trays, bottles and bags, will be developed within one to five years,” says Prof Blennow.