The University of Copenhagen has created a new bio-friendly material made from barley starch mixed with sugar beet waste fibers - a strong material that turns into compost if it ends up in nature. In the long run, the researchers hope their invention will help curb plastic pollution while reducing the climate footprint of plastic production.
Huge islands of plastic float in our oceans and its tiny particles are present in our bodies. Plastic's durability, malleability and low cost make them ubiquitous, from packaging to clothing to airplane parts. But plastics have drawbacks. Plastics pollute nature, are difficult to recycle, and their production emits more carbon dioxide than all air traffic combined.
Now, researchers at the University of Copenhagen's Department of Plant and Environmental Sciences have invented a new material made from modified starch that can be completely broken down in nature, and in just two months. The material is made from natural plant material from crops and can be used for food packaging, among other things.
"We have a huge problem with plastic waste, and recycling doesn't seem to be a solution. So we developed a new bioplastic that is stronger and more water-resistant than existing bioplastics. At the same time, our material is 100 percent biodegradable and can be converted into compost by microorganisms if it ends up somewhere other than a garbage bin," said Prof. Andreas Blennow of the Department of Plant and Environmental Sciences.
Only about 9% of the world's plastic is recycled; the rest is either incinerated, ends up in nature, or dumped in huge plastic landfills.
Bioplastics already exist, but the name is misleading, Blennow said. While today's bioplastics are made from biologically derived materials, only a limited portion is actually biodegradable, and only under special conditions in industrial composting plants.
"I don't think the name is appropriate because the most common types of bioplastics don't break down easily if they are thrown out into nature. The process can take many years, and some of them will continue to pollute in the form of microplastics. Specialized facilities are needed to break down bioplastics. Even so, only a very limited portion of it can be recycled, and the rest ends up as waste," the researchers said.
Starch from barley and sugar industry wastes
The new material is a so-called biocomposite, consisting of several different substances that break down naturally. Its main components, straight-chain starch and cellulose, are common in the plant kingdom. Gibberellic starch is derived from many crops, including corn, potatoes, wheat and barley.
The research group, which has set up a spin-off company together with researchers from Aarhus University, has developed a barley variety that produces pure straight-chain starch in its kernels. This new variety is important because pure rectilinear starch is much less likely to turn into a paste when interacting with water than regular starch.
Cellulose is a carbohydrate found in all plants, and we know it from cotton and flax fibers as well as wood and paper products. The cellulose the researchers used is a so-called nanocellulose, made from local sugar industry waste. These nanocellulose fibers are a thousand times smaller than flax and cotton fibers and help improve the mechanical strength of the materials.
"Straight-chain starch and cellulose form long, strong molecular chains. Combining them allows us to create a durable, flexible material that has the potential to be used in shopping bags and the packaging of goods we now wrap in plastic," Blennow said.
New biomaterials are produced by dissolving raw materials in water and mixing them together or heating them under pressure. In this way, small "pellets" or chips can be produced, which can then be processed and compressed into the desired form.
So far, the researchers have only produced prototypes in the lab. But according to Blennow, it will be relatively easy to start production in Denmark and many other parts of the world.
"The entire chain of production of enriched rectilinear starch already exists. In fact, millions of tons of pure potato and corn starch are produced every year and used by the food industry and elsewhere. Therefore, for the mass production of this material, easy access to most of our ingredients is guaranteed," he said.
Can reduce the plastic problem
Blennow and his colleagues are now working on a patent application that, once approved, could pave the way for the production of new biocomposites. Because, despite the huge amount of money invested in sorting and recycling our plastics, the researchers don't believe it will actually work. Doing so should be seen as a transitional technology until we say goodbye to fossil-based plastics.
"Recycling plastics efficiently is no easy task. The different substances in plastics have to be separated from each other, and there are significant differences between plastic types, which means that the process has to be carried out in a safe way so that contaminants do not end up in the recycled plastic.
"At the same time, the state and consumers must categorize plastics. It's a daunting task, and I don't think we'll succeed. Instead, we should reconsider utilizing new materials that perform like plastic but don't pollute the planet," Brenau said.
The researcher has already worked with two Danish packaging companies to develop prototypes for food packaging, among other things. He also envisions many other uses for the material, such as car interiors for the automotive industry. While it is difficult to say when this bio-friendly barley-based plastic will hit the shelves, the researcher predicts that the new material could become a reality in the foreseeable future.
"We are very close to the point where we can actually start producing prototypes in collaboration with our research teams and companies. I think it's realistic to develop different prototypes for flexible and rigid packaging, such as trays, bottles and bags, within one to five years," Blennow concludes.
