What kind of plastic is durable but “melts” in the ocean?
February 22nd 19:09
As marine pollution caused by plastic waste becomes a global issue, research and development is underway to solve the problem not only by eliminating waste but also by changing ways of thinking.
Durable when in use.
However, due to the ``device'' in place, it will naturally decompose if it flows into the sea or sinks.
The aim is to create a revolutionary plastic that is environmentally friendly.
(Matsuyama Broadcasting Station reporter Yoshino Teshigahara)
Most of the garbage washed ashore is fishing gear.
Ainan Town in Ehime Prefecture is famous for its fishing industry, including cultivating red sea bream and pearls.
Research is being carried out in this town to develop plastics to make environmentally friendly fishing gear.
In order to see how the plastic we are developing will break down in the ocean, we are submerging over 1,000 samples of various types of plastic in a cage to observe changes.
In fact, research shows that fishing gear accounts for the majority of the plastic waste that washes up on beaches in Japan.
According to a survey conducted by the Ministry of the Environment in fiscal 2016, of the plastic waste that washed ashore on beaches around Japan, ``fishing nets and ropes'' accounted for the largest portion by weight at 41.8%, and approximately 60% of all fishing gear. .
“It just keeps flowing out.”
Why does fishing gear wash ashore as garbage?
Marine pollution caused by plastic waste has become a problem in Ainan Town, where the experiment is being conducted.
Hiroki Tachibana, head of the Ainan Fisheries Association, says that even if fishermen are careful, some items end up being washed away as garbage, such as when fishing nets break during fishing or when floats are washed away by bad weather. .
Hiroki Tachibana, Chairman of the Ainan Fisheries Association
: ``We have a strong awareness that we should never throw away garbage, but if you leave it on the edge of the coast, there is a possibility that it may flow into the ocean. I think there are times when they get swept away by the waves during spring tides."
It's durable, but will it break down?
Therefore, research is being conducted to find out whether it is possible to create environmentally friendly fishing gear by developing plastics that naturally decompose in the ocean.
The research leader is Professor Kozo Ito of the University of Tokyo Graduate School.
We are working with a team of experts and companies who are familiar with marine debris countermeasures to proceed with development.
Professor Kozo Ito of the University of Tokyo Graduate School
: ``What we are trying to create is an ideal plastic that is durable and unbreakable when in use.If it happens to enter the ocean by mistake, it will quickly decompose.'' I would like to.”
Professor Ito is aiming to develop plastics that begin to decompose only when various conditions such as light, heat, and the action of microorganisms come together.
That's how it works.
We incorporate various ``gifts'' into plastics by adjusting ingredients such as enzymes and additives in advance.
The idea is that when conditions such as light, heat, oxygen, enzymes, and the action of microorganisms are met in the ocean, this "mechanism" will work and decomposition will begin.
By using biological materials as raw materials, they will eventually decompose into water and carbon dioxide.
As a result, for example, when the fishing gear is used in shallow water or on a boat, it maintains its durability, but when the fishing line or net becomes garbage and sinks to the seabed, it decomposes and the plastic garbage on the seabed is removed by fish. We believe this will also help prevent damage caused by fish being eaten by sea creatures or fishing gear becoming entangled with sea creatures.
Until now, plastics that decompose in the sea have been developed, but they were not durable enough to be used in fishing gear.
Verification Will the decomposition proceed?
The research team is currently examining how to adjust and process the ingredients to promote decomposition.
In Ainan Town, we are observing how various ingredients actually change in the sea, where they are affected by waves and the way they are exposed to light.
The number of samples is over 1000.
In December 2023, we pulled out the plastic that had been submerged in the ocean for half a year.
As a result, it was confirmed that the material being developed decomposed more rapidly than ordinary plastics.
Professor Kozo Ito of the University of Tokyo Graduate School:
"If you push it a little, it will crack. Even if you touch it a little, it will break right away, so I think it would have collapsed right away. I think it's going well. It's not going as expected. Kanato”
To strengthen Japan's competitiveness
Another goal is to use this plastic to increase Japan's international competitiveness.
It has been selected as one of the nation's large-scale ``moonshot research and development'' projects that support challenging development based on bold ideas, similar to the American Apollo program that took humans to the moon.
NEDO (New Energy and Industrial Technology Development Organization), which supports the research, says that demand for this plastic can be expected worldwide.
Tomoo Yoshida, Director of the NEDO Moonshot Research and Development Project Promotion Office
: ``Plastic that has a ``switch function'' that starts to decompose under conditions such as light and heat is extremely unique and is attracting attention internationally. I think this technology can be used around the world."
Japanese companies also have expectations
Major companies are also participating in research and development in the hope that it will become a large market in the future.
Among these, Mitsubishi Chemical, a major chemical manufacturer, is attracting attention as a raw material for use in things such as plastic bags and agricultural sheets.
A representative from Mitsubishi Chemical said
, ``As a company that makes plastics, we have to consider environmental considerations, and even though it would be too difficult for a single company to tackle this alone, we are determined to work together with other companies and researchers. I think it is an advantage that we are able to carry out research and development.”
In addition, experiments are being conducted to see if this plastic can be used in tires.
This is because in recent years, it has been pointed out that worn-out rubber from tires is flowing into the ocean and becoming microplastics.
The impact on the environment is not yet clear, but according to a study published by UNEP in 2018, about 47% of microplastics with a size of 5 mm or less that leak into the environment come from tires. It is said that.
Therefore, our research aims to maintain the strength of tires while allowing worn rubber to decompose naturally when it flows into the ocean.
Using the newly developed material, we aim to create a prototype tire by 2029.
The good side of plastic
Professor Ito says he wants to balance the benefits of durable plastic with environmental friendliness.
Professor Kozo Ito of the University of Tokyo Graduate School
: ``Plastic has its good and bad sides, but by solving the bad and lacking aspects with a project like this, we can get recognition so that we can use the good parts of plastic for a long time. I would like to do so.”
On the other hand, further research and verification is needed to process and adjust the ingredients so that it remains durable and practical as fishing gear even in the ocean, yet decomposes when it becomes garbage.
Furthermore, even if a prototype is created, there are still many challenges to commercialization, such as whether it can be produced at a cost that will allow for widespread use.
However, the development of a plastic with contradictory functions, such as being durable when in use but degrading once it enters the ocean, was something fishermen we interviewed said, ``It's unimaginable now, but it would be truly amazing if it were realized.'' '' he said.
Around the world, there is a growing movement to tackle the problem of ocean plastics in earnest, with countries negotiating to create an international treaty to prevent plastic pollution.
We can't take our eyes off the future of this research to see how much the research being conducted in Japan will contribute to global issues and lead to competitiveness.
(Broadcast on “Himepon!” on January 16th)
Yoshino Teshigahara ,
reporter at Matsuyama Broadcasting Station
Joined the station in 2019
I am interested in and reporting on the marine plastic waste problem.I
like to stare at the beautiful sea of Ehime.