Osaka University creates plastic that decomposes in seawater

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SUITA, Osaka Prefecture–An Osaka University-led team said it has developed a plant-based plastic that can decompose in seawater.

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The materials are relatively inexpensive, the manufacturing method is simple, and the final product is stronger than normal plastics, the team said.

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Moreover, the discovery could help to alleviate the global problem of plastic waste polluting the seas.

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“We would first like to use it as food packaging materials, which are very familiar to people and are often contained in the waste in the sea,” said Hiroshi Uyama, a professor of engineering at Osaka University. “I hope that this will be a part of the solution to the issue and raise the interest of people.”

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The team used starch contained in cassava, a raw material for tapioca, and cellulose contained in wood pulp.

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The materials were dissolved in water, spread thinly and then turned into a transparent sheet through heating.

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One sheet is about 100 micrometers thick, and it has more than twice the strength of widely used plastics made of polyethylene, according to the team.

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The researchers placed a sheet in seawater swarming with micro-organisms. One month later, it had been torn to shreds, the micro-organisms membranous aggregate formed on the surface.

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The team believes an enzyme held by the micro-organisms caused the decomposition of the sheet. In water with fewer micro-organisms, the sheet did not decompose.

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Other plastics that can be decomposed by living creatures have been developed, but few of those plastics have been decomposed in seawater that contains fewer micro-organisms, compared with land.

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