January 1, 2026.
Hope may be in sight for the end of microplastics in our Oceans and Food Supplies.
In November 2024 Researchers led by Takuzo Aida at the RIKEN Center for Emergent Matter Science (CEMS) announced they developed a durable plastic that won’t contribute to microplastics pollution in our oceans. Their claim is that the new material is as strong as conventional plastics and biodegradable, but what makes it special is that it breaks down in seawater. The new plastic is therefore expected to help reduce harmful microplastics pollution that accumulates in oceans and soil and eventually enters the food chain. The experimental findings were published Nov 22 2024 in Science.
Scientists have been trying to develop safe and sustainable materials that can replace traditional plastics, which are non-sustainable and harm the environment. While some recyclable and biodegradable plastics exist, one big problem remains. Current biodegradable plastics like PLA often find their way into the ocean where they cannot be degraded because they are water insoluble. As a result, microplastics—plastic bits smaller than 5 mm—are harming aquatic life and finding their way into the food chain, including our own bodies.
In their 2024 study, Aida and his team focused on solving this problem with supra-molecular plastics—polymers with structures held together by reversible interactions. The new plastics were made by combining two ionic monomers that form cross-linked salt bridges, which provide strength and flexibility. In the initial tests, one of the monomers was a common food additive called sodium hexametaphosphate and the other was any of several guanidinium ion-based monomers. Both monomers can be metabolized by bacteria, ensuring biodegradability once the plastic is dissolved into its components.
“While the reversible nature of the bonds in supra-molecular plastics have been thought to make them weak and unstable,” says Aida, “our new materials are just the opposite.” In the new material, the salt bridges structure is irreversible unless exposed to electrolytes like those found in seawater. The key discovery was how to create these selectively irreversible cross links.
As with oil with water, after mixing the two monomers together in water, the researchers observed two separated liquids. One was thick and viscous and contained the important structural cross linked salt bridges, while the other was watery and contained salt ions. For example, when sodium hexametaphosphate and alkyl diguanidinium sulfate were used, sodium sulfate salt was expelled into the watery layer. The final plastic, alkyl SP2, was made by drying what remained in the thick viscous liquid layer.
The “desalting” turned out to be the critical step; without it, the resulting dried material was a brittle crystal, unfit for use. Re-salting the plastic by placing it in salt water caused the interactions to reverse and the plastic’s structure destabilized in a matter of hours. Thus, having created a strong and durable plastic that can still be dissolved under certain conditions, the researchers next tested the plastic’s quality.
The new plastics are non-toxic and non-flammable—meaning no CO2 emissions—and can be reshaped at temperatures above 120°C like other thermoplastics. By testing different types of guanidinium sulfates, the team was able to generate plastics that had varying hardnesses and tensile strengths, all comparable or better than conventional plastics. This means that the new type of plastic can be customized for need; hard scratch resistant plastics, rubber silicone-like plastics, strong weight-bearing plastics, or low tensile flexible plastics are all possible. The researchers also created ocean-degradable plastics using polysaccharides that form cross-linked salt bridges with guanidinium monomers. Plastics like these can be used in 3D printing as well as medical or health-related applications.
Lastly, the researchers investigated the new plastic’s ability to be recycled and biodegradability. After dissolving the initial new plastic in salt water, they were able to recover 91% of the hexametaphosphate and 82% of the guanidinium as powders, indicating that recycling is easy and efficient. In soil, sheets of the new plastic degraded completely over the course of 10 days, supplying the soil with phosphorous and nitrogen similar to a fertilizer.
“With this new material, we have created a new family of plastics that are strong, stable, recyclable, can serve multiple functions, and importantly, do not generate microplastics,” says Aida. While promising no "deals" were announced to use this product.
Better News .....In December 2025 Riken announced that Researchers led by Takuzo Aida at the RIKEN Center for Emergent Matter Science (CEMS) in Japan have one-upped themselves in their quest to solve our microplastics problem.
In a recent study published in the Journal of the American Chemical Society they report a new type of plastic made from plant cellulose, the world’s most abundant organic compound. The new plastic is strong, flexible, and capable of rapid decomposition in natural environments, setting it apart from other plastics marketed as biodegradable.
Microplastics are a global contaminant found in nearly every ecosystem, from the soil and the ocean to the animals and plants that live there. They have even been found in human tissue and the bloodstream where they likely have adverse effects. While biodegradable plastics and even some cellulose-derived plastics (cellulose nitrate or cellulose acetate) are not new, most plastics labeled “biodegradable” do not degrade in marine environments or they take a very long time to degrade, leaving microplastics behind in the meantime.
Last year, Aida and his team developed a plastic that could quickly degrade in salt water within several hours, without leaving any microplastics behind. That plastic was a supramolecular plastic made from two polymers held together by reversible interactions called “salt bridges”. In the presence of salt water, the bonds holding the two polymers together came apart and the plastic decomposed. But this plastic wasn’t as practical as it could be for real-world manufacture.
The new plant-based plastic is similar, except that one of the two polymers is a commercially available, FDA approved, biodegradable wood-pulp derivative called carboxymethyl cellulose. Finding a compatible second polymer took some trial and error, but eventually the team found a safe cross-linking agent made from positively charged polyethylene-imine guanidinium ions. When the cellulose and guanidinium ions were mixed in room temperature water, the negatively and positively charged molecules attracted each other like magnets and formed the critical cross-linked network that makes this kind of plastic strong. At the same time, the salt bridges holding the network together broke as expected in the presence of salt water. To avoid unintentional decomposition, the plastic can be protected with a thin coating on the surface.
So far so good. But even though the new plastic decomposed quickly, it initially suffered from being too brittle because of the cellulose. The resulting plastic was colorless, transparent, and extremely hard, but had a fragile glass-like quality. What the team needed was a good plasticizer, some small molecule they could add to the mix to make the plastic more flexible, yet remain hard.
After much experimenting, they discovered that the organic salt choline chloride worked wonders. By adding varying amounts of this FDA-approved food additive to the plastic, the researchers were able to fine-tune exactly how flexible they wanted the plastic to be. Depending on the amount of choline chloride, the plastic can range from being hard and glass-like to being so elastic that it can be stretched up to 130% of its original length. It can even be made into a strong yet thin film with a thickness of only 0.07 mm.
The improvements on the original design are not trivial. “While our initial study focused mostly on the conceptual,” explains Aida, “this study shows that our work is now at a more practical stage.” The new carboxymethyl cellulose supramolecular plastic, dubbed CMCSP, is as strong as conventional petroleum-based plastics and its mechanical properties can be adjusted as needed, without spoiling the intrinsic transparency, process-ability, seawater dis-sociability, or close-loop recycle-ability. By using common and inexpensive FDA-approved biodegradable ingredients, Aida and his team have ensured that their plastic will be able to move quickly to real-world, practical applications.
“Nature produces about one trillion tons of cellulose every year,” says Aida. “From this abundant natural substance, we have created a flexible yet tough plastic material that safely decomposes in the ocean. They claim this technology will help protect the Earth from plastic pollution.”
Consumer Demand for this product will be the next driving factor needed for change. Retooling factories is expensive and until consumers refuse to buy beverages and food packaged using the current plastic it is highly unlikely they will make the needed changes. Of course they may be motivated by the risk of legal action though the research is years away from proving damages.
While the current advantages of plastic is real and a true value our hope is the food and beverage companies along with other manufacturers want to get ahead of their legal risk by making the changes as soon as possible.