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Japan Science

Scientists in Japan Develop Plastic That Dissolves in Seawater Within Hours (reuters.com) 52

Researchers in Japan have developed a plastic that dissolves in seawater within hours, offering up a potential solution for a modern-day scourge polluting oceans and harming wildlife. From a report: While scientists have long experimented with biodegradable plastics, researchers from the RIKEN Center for Emergent Matter Science and the University of Tokyo say their new material breaks down much more quickly and leaves no residual trace.

At a lab in Wako city near Tokyo, the team demonstrated a small piece of plastic vanishing in a container of salt water after it was stirred up for about an hour. While the team has not yet detailed any plans for commercialisation, project lead Takuzo Aida said their research has attracted significant interest, including from those in the packaging sector.

Scientists in Japan Develop Plastic That Dissolves in Seawater Within Hours

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  • Oh, (Score:5, Funny)

    by backslashdot ( 95548 ) on Wednesday June 04, 2025 @01:34PM (#65427561)

    so they purchased it on Temu?

  • Now we can just directly dump all our trash into the ocean guilt-free.

    • Sources (Score:5, Informative)

      by JBMcB ( 73720 ) on Wednesday June 04, 2025 @01:49PM (#65427603)

      Most of this is coming from Asia, followed by Africa and South America, mainly because some areas use rivers as their primary garbage disposal system. They are already dumping their garbage into the ocean without caring about it.

      https://theoceancleanup.com/sources/

      • by Anonymous Coward

        Yet Western nations kept sending all their plastic junk to these nations.

      • Re:Sources (Score:4, Informative)

        by DesertNomad ( 885798 ) on Wednesday June 04, 2025 @02:41PM (#65427723)

        Interesting. According to the link you provided, specifically the page called "The Great Pacific Garbage Patch", they concluded

        "This indicated that over 75% of plastics in the GPGP – not only the 46% made up of fishing nets, as we discovered in 2018 – are attributable to offshore fishing activities. More research will be required in order to discover if this also applies to the other garbage patches around the world."

        While there are contributions from all those rivers, it seems from the above statement that the stuff floating around in the Pacific gyre is mostly from offshore fishing. Maybe that's the first place we should look?

        • That's just the Pacific patch. The stuff eminiating from the rivers in Asia ends up caught in hundreds of patches of junk between the islands in the South China Sea and the Gulf of Thailand. You're right that marine waste needs to be fixed, too, but plastic that dissolves in seawater isn't going to fix that, as nobody would use it in marine applications.
      • Is coming from Western countries right? We send it to them and they use it for various purposes up to and including burning it for fuel.

        There's a video about Thailand where one of the Staples of their diet is fried tofu and the tofu is fried using heat from burned plastic. So everybody is basically eating and breathing prodigious amounts of plastic because well, that's what happens. But it's super cheap fuel because it's waste from other countries.

        It turns out incredibly dirt poor people don't use
        • by JBMcB ( 73720 ) on Wednesday June 04, 2025 @10:11PM (#65428558)

          Is coming from Western countries right?

          Some of it is. Not most of it. China stopped importing plastic waste about 7 years ago, which kind of tanked the market for waste plastic, to the point that governments were paying recycling companies to get it off their hands. Some entrepreneurs set up illegal "recycling" centers in Vietnam and Cambodia, masking the destinations with intermediaries in South America, as you had to be a certified recycling facility to get the payouts.

          That's the situation now. Dumping garbage in these rivers has been happening for decades. The fake recyclers didn't come up with the idea. They figure no one would notice the extra junk mixed in with what was already there.

          Also, even though China stopped importing recycled plastic, the Yangtze has the most plastic pollution of any river in the world. That's not coming from western sources.

      • Half correct, for a few decades the west has been disposing its waste in Asia, Africa and South America for “processing” where it ends up in rivers..
  • Unfortunately, a lot of Japanese cuisine is chemically indistinguishable from seawater.
  • So basically, you're dumping plastic into seawater, and then maybe it will not be microplastics thanks to bacteria. But maybe it will!

    Plastics are amazing, but their use should be drastically limited to places where they are justified and will not contribute to the plague of pollution. Maybe certain car parts and appliance parts, for instance, but not throughout packaging. Plastic packaging is just fucking awful.

    • My first thought was if I have 1 gallon of seawater and a 4 pound block of this stuff, will I end up making salty goop? What happens to it or what does it become after it "dissolves"?

      From the article "As salt is also present in soil, a piece about five centimetres (two inches) in size disintegrates on land after over 200 hours, he added.". So basically this stuff isn't going to be useful in pretty any application other than maybe some highly specialized environments. Humans have salt too, so just touchin

  • So it "dissolves"... into what? Last I heard, microplastics in our water (and later, our food) are raising ever more concerns about human health.

    • by Monoman ( 8745 )

      Don't' worry it will be harmless and even it is isn't, the levels will be acceptable. You can always trust companies and government officials to do the right thing.

      https://en.wikipedia.org/wiki/... [wikipedia.org]

    • If trash will end on the oceans anyway, it's better to dissolve into microplastics than not dissolve and trap marine life.
    • Re: (Score:3, Informative)

      From TFA:

      "Aida said the new material is as strong as petroleum-based plastics but breaks down into its original components when exposed to salt. Those components can then be further processed by naturally occurring bacteria, thereby avoiding generating microplastics that can harm aquatic life and enter the food chain.
      As salt is also present in soil, a piece about five centimetres (two inches) in size disintegrates on land after over 200 hours, he added."

  • by wakeboarder ( 2695839 ) on Wednesday June 04, 2025 @01:51PM (#65427607)

    Gatorade then, just water.

  • ...they will sell sailboats made of it, advertising them as "environmental friendly".
    • Typically it takes about 20-30 years for a plastic sailboat to disintegrate due to UV, water intrusion and lack of maintenance. On the other hand a good captain at the helm can sink a ship in minutes.
      I suspect a lot of plastics are dust from the hulls and decks of "classic plastic" boats - polyester gelcoat, dacron sails, ropes generally degrade into microplastics. That said, the number of classic plastic boats out there is tiny compared to all the rapidly disintegrating polyester clothing in the world's wa

  • by Chelloveck ( 14643 ) on Wednesday June 04, 2025 @01:57PM (#65427625)

    RIKEN Center for Emergent Matter Science

    Well, if *that* doesn't sound like the opening location shot of a kaiju movie, I don't know what does!

    • RIKEN Center for Emergent Matter Science

      Well, if *that* doesn't sound like the opening location shot of a kaiju movie, I don't know what does!

      I was gonna ask, isn't that one of the firms in Pacific Rim 2?

  • I like the idea, but from what I've read most of the plastic pollution in the ocean is actually fishing gear. I don't think making fishing gear out of plastic that dissolves in sea water is going to be commercially viable. The plastic they use for fishing gear is actually very expensive high grade plastic, and the ocean cleanup group actually collects it and sells it because it's worth money.
  • This will just result in even more nanoplastic pollution in the ocean.

  • Does it have electrolytes? Because that's what plants crave.

  • I do not think that there is a market for soft drink bottles that dissolve in salty water, since that is essentially what most soft drinks are, flavored salty water. The same applies to a lot of other uses. The primary advantage of plastics as packaging material is their inertness. The real solution has been staring us in the face for years, go back to glass. Yes, in is heavier, but it cheap, totally recyclable and has chemically inert.
  • Just because you can't see something doesn't mean it isn't still there.

  • Salty, humid environments are all around us, even though we don't realise it while we look around us at everyday objects every day. This artificial, short-lived plastic wouldn't survive in consumer-grade products.

  • So, typical uses include life preservers, boat hulls, electrical insulation...

  • Is that there's a ton of people out there terrified of fluoride or microchips in vaccines who are perfectly okay with a spoon's worth of microplastic in their brains.

    I don't want to suggest that there is a correlation since we all have the same spoons worth of plastic, but it is impressive how oil and plastic industry propaganda works.
  • the perfect container for soup

  • The main benefit of plastic is that it is durable and not-usually-very-reactive.
  • by hadleyburg ( 823868 ) on Wednesday June 04, 2025 @06:32PM (#65428260)

    There has been a strong move in recent years to stop the use of single use plastics (essentially plastic bags that you get with your shopping). In many countries now, people bring their own bag to the shops, and being given your purchase unwrapped is considered normal and acceptable.

    Japan on the other hand, has a culture of wrapping things that are given from one person to another, so it is difficult for shops to give up the idea of handing over the purchase to the customer unwrapped - The customer would see it as a lapse in service. So although plastic shopping bags are on the decline in Japan, you still have the option of buying them in the supermarket, and a lot of plastic is still used in packaging goods for sale.

    In this context I can see why research into a more environmentally friendly plastic might be considered important in Japan.

  • The actual research (Score:4, Informative)

    by mattr ( 78516 ) <mattr.telebody@com> on Thursday June 05, 2025 @07:14AM (#65429070) Homepage Journal

    Apparently it breaks down to a food additive and a fertilizer..

    https://www.riken.jp/en/news_p... [riken.jp]
    After screening various molecules, the team found that a combination of sodium hexametaphosphate (a common food additive) and guanidinium ion-based monomers (used for fertilizers and soil conditioners) formed ‘salt bridges’ that bind the compounds together with strong cross-linked bonds. These types of bonds serve as the ‘lock’, providing the material with strength and flexibility, explains Aida.
    “Screening molecules can be like looking for a needle in a haystack,” he says. “But we found the combination early on, which made us think, ‘This could actually work’.”
    In their study, Aida’s team produced a small sheet of this supramolecular material by mixing the compounds in water. The solution separated into two layers, the bottom viscous and the top watery, a spontaneous reaction that surprised the team. The viscous bottom layer contained the compounds bound with salt bridges. This layer was extracted and dried to create a plastic-like sheet.
    The sheet was not only as strong as conventional plastics, but also non-flammable, colorless and transparent, giving it great versatility. Importantly, the sheets degraded back into raw materials when soaked in salt water, as the electrolytes in the salt water opened the salt bridge ‘locks’. The team’s experiments showed that their sheets disintegrated in salt water after 8 and a half hours.
    The sheet can also be made waterproof with a hydrophobic coating. Even when waterproofed, the team found that the material can dissolve just as quickly as non-coated sheets if its surface is scratched to allow the salt to penetrate, says Aida.

    https://www.science.org/doi/10... [science.org]

    Editor’s summary

    A strong, glassy supramolecular polymer has been shown to prevent the formation of marine microplastics by slowly dissolving in salt water into metabolizable compounds. Cheng et al. show that salt bridging between sodium hexametaphosphate or sulfated polysaccharides and guanidinium sulfates expels sodium sulfate to create a cross-linked network that is stable until the electrolytes are added back. The dried material is a moldable and recyclable thermoplastic that can be water stabilized with hydrophobic coatings. —Phil Szuromi
    Abstract

    Plastics that can metabolize in oceans are highly sought for a sustainable future. In this work, we report the noncovalent synthesis of unprecedented plastics that are mechanically strong yet metabolizable under biologically relevant conditions owing to their dissociative nature with electrolytes. Salt-bridging sodium hexametaphosphate with di- or tritopic guanidinium sulfate in water forms a cross-linked supramolecular network, which is stable unless electrolytes are resupplied. This unusual stability is caused by a liquid-liquid phase separation that expels sodium sulfate, generated upon salt bridging, into a water-rich phase. Drying the remaining condensed liquid phase yields glassy plastics that are thermally reshapable, such as thermoplastics, and usable even in aqueous media with hydrophobic parylene C coating. This approach can be extended to polysaccharide-based supramolecular plastics that are applicable for three-dimensional printing.

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