Japan Create Plastic That Dissolves in Seawater Within Hours

Imagine if the plastic we use every day could simply disappear when it falls into the ocean—leaving no trace, no pollution, and no harm to marine life.

It sounds like science fiction, doesn’t it? But that’s exactly what scientists in Japan are now developing.

A research team from the RIKEN Center for Emergent Matter Science and the University of Tokyo recently announced their breakthrough: a new type of plastic that can fully degrade in seawater within just one hour. No toxic residue, no microplastic traces, and—most importantly—completely safe for the environment.

Published in the journal Science on World Environment Day (June 5), this discovery offers new hope in the fight against the global plastic pollution crisis.

What Makes This Plastic Different?

This isn’t just another “biodegradable” plastic as we’ve known it, many so-called biodegradable plastics still leave behind micro- and nanoplastic particles that pose serious environmental risks.

In contrast, this new material fully dissolves in seawater and breaks down into natural compounds like nitrogen and phosphorus, which can be absorbed and reused by marine microbes and plants.

What’s even more impressive is that the material retains the strength and functionality of conventional petroleum-based plastics. But once it comes into contact with saltwater, it degrades into its base components, which can then be digested by naturally occurring bacteria without producing further pollution.

What Is It Made Of?

The key to this breakthrough lies in a unique combination of compounds: sodium hexametaphosphate (commonly used as a food additive) and a monomer based on guanidinium ions (often found in fertilizers and soil conditioners).

According to project leader Takuzo Aida, finding the right molecular formula was no easy task—like looking for a needle in a haystack. But the team succeeded earlier than expected, offering renewed optimism for the future of sustainable materials research.

Proven to Rapidly Degrade in Sea and Soil

In laboratory tests conducted in Wako City, near Tokyo, a sheet of this transparent plastic completely disappeared within 60 minutes after being stirred in seawater.

Even more impressively, in salt-containing soil, a five-centimeter piece of the plastic degraded in approximately 200 hours, without any special treatment or complex technology.

This material is also reported to be flame-resistant, non-toxic to humans, and does not emit carbon dioxide during decomposition—factors that make it significantly more sustainable than many current alternatives.

Challenges and Future Potential

As promising as it sounds, this “magic plastic” is not yet ready for mass production. Researchers are still fine-tuning a coating technique that would allow the material to function like regular plastic during use, while still being able to dissolve when discarded into the environment.

Still, several major companies in the packaging industry have already expressed interest in the technology. This is not surprising, especially in light of stark warnings from the United Nations that without urgent action, plastic pollution in the ocean could triple by 2040, reaching 37 million tons annually.

The Real Threat of Microplastics

Microplastics—plastic particles less than 5 millimeters in size—have now been detected in nearly every corner of the planet, from the depths of the Mariana Trench to the summit of Mount Everest. These particles have even entered the human body, including the brain, placenta, and bloodstream.

That’s why many scientists are calling for the microplastic crisis to be declared a global emergency. Innovations like this seawater-dissolvable plastic could be a crucial step toward breaking a destructive cycle of invisible but dangerous pollution.

A Legacy for Future Generations

“Children cannot choose the planet they will live on. It is our duty as scientists to ensure that we leave them with the best possible environment,” said Takuzo Aida, underlining the urgency of their mission.

This breakthrough is not just about technology, it’s about moral responsibility. As the world races to find real solutions to the plastic waste crisis, Japan may have just taken a major leap ahead.