Mallory Parker, a PhD student in materials science and engineering at the University of Washington, holds a cube of bioplastic made from spirulina. Mark Stone/University of Washington
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Plastics are everywhere. They are used to make food packagingBags, Bottles of water and for many other common applications. As they break down, their tiny particles – known as microplastics – end up in the ocean, on the highest peaks, in our lungs and in our blood.
The problem with plastics is that they remain in the environment for years, posing risks to humans, animals and the environment. But what if there was another type of plastic that would biodegrade in your backyard composter as quickly as a banana peel?
A group of researchers led by scientists from the University of Washington has developed new bioplastics that biodegrade naturally and relatively quickly – unlike traditional plastics, which do not biodegrade, or other types of bioplastics, which must be processed in commercial facilities to biodegrade – and they are made from the cells of the blue-green cyanobacterium known as spirulina.
“We were driven to create bioplastics that are both bio-derived and biodegradable in our backyards, while also being transformable, scalable and recyclable,” said the lead author of the study Eleftheria Roumeli, UW assistant professor of materials science and engineering, in a University of Washington press release. “The bioplastics we have developed, using only spirulina, not only have a degradation profile similar to organic waste, but are also on average 10 times stronger and stiffer than previously reported spirulina-based bioplastics. These properties open up new possibilities for the practical application of spirulina-based plastics in various industries, including disposable food packaging or household plastics, such as bottles or trays.
For the study, the researchers formed the spirulina powder into a multitude of shapes using heat and pressure, similar to how conventional plastics are processed and created. The mechanical properties of spirulina plastics are similar to petroleum-derived single-use plastics.
The study, “Making Strong and Rigid Bioplastics from Spirulina Whole Cells,” was published in the journal Advanced functional materials.
Scientists chose spirulina for their bioplastics because it is already used for beauty products And food and can be grown on a large scale. As they grow, the spirulina cells sequester carbon dioxidewhich means that as a raw material for plastics, spirulina is not only carbon neutralbut has the potential to be carbon negative.
“Spirulina also has unique fire-resistant properties,” said the study’s lead author, Hareesh Iyer, a UW materials science and engineering doctoral student, in the press release. “When exposed to fire, it extinguishes instantly, unlike many traditional plastics which burn or melt. This fire-resistant characteristic makes spirulina-based plastics advantageous for applications where traditional plastics may not be suitable due to their flammability. An example might be plastic racks in data centers, as systems used to cool servers can get very hot. »
Because the research team used a similar processing approach to traditional plastics with their bioplastics, large-scale manufacturing of the spirulina-based materials would be easier.
“That means we wouldn’t have to redesign manufacturing lines from scratch if we wanted to use our materials on an industrial scale,” Roumeli said. “We removed one of the common barriers between the lab and scaling up to meet industrial demand. For example, many bioplastics are made from molecules extracted from biomass, such as algae, and mixed with performance modifiers before being molded into films. This process requires the materials to be in the form of a solution before casting, and it is not scalable.
Making bioplastics from spirulina has been done before, but the bioplastics proposed by the UW-led research team are stiffer and stronger. They are also recyclable. Researchers altered processing conditions such as time, pressure and temperature to improve the bonding and microstructure of bioplastics, studying their stiffness, toughness and strength along the way.
Plastics still have hurdles before they are ready for industrial use, such as being sensitive to water and somewhat brittle.
“You wouldn’t want these materials falling in the rain,” Iyer said in the press release.
Researchers are still examining the fundamentals of bioplastics and hope to create an assortment of bioplastics for various uses, similar to petroleum-based plastics.
“Biodegradation is not our preferred end-of-life scenario,” Roumeli said. “Our spirulina bioplastics are recyclable through mechanical recycling, which is very accessible. However, people don’t recycle plastics often, so it’s an added bonus that our bioplastics degrade quickly in the environment.