Compostable Plastic Wrap Made from Seaweed Withstands Heat–and Biodegrades in Weeks

Sargassum seaweed – rjsinenomine CC 2.0.

An invasive seaweed species from the Caribbean has been turned into a compostable plastic wrap that has the potential for mass production.

Furthermore, it may have the properties to transform the whole supply chain of this ubiquitous product used in huge quantities every day in restaurants around the world.

The breakthrough comes from the University of Leeds, in the UK, where Keeran Reed and his colleagues were looking to turn the brown seaweed species called sargassum, (Sargassum natans) which inundates the shores of Reed’s home of Trinidad and Tobago, into a sort of biopolymer.

Sargassum is made up of long chains of molecules similar to those found in conventional plastic. the researchers found that mixing it with acid, salt, and some chemicals rendered it thicker and pliable.

They then turned it into sheets of film like normal plastic wrap to study how it held up in heated conditions, and when thrown into the compost bin. Existing biodegradable plastics can take months, even more than a year, to break down in a compost heap. By contrast, the sargassum needed two to three weeks.

Despite this rapid decomposition, the films were robust and held together at temperatures of around 450°F (230°C). Also, the film didn’t leach out any of the chemicals when left in water over a period of 10 days, meaning it can be safely used to cover moist containers of food like chopped fruit.

“Studying the whole supply chain really is where ideas for sustainable materials make it or don’t. We want to find one best application for our material and study the environmental impact of pursuing it from the lab to the consumer,” Koon-Yang Lee at Imperial College London, part of the research team, told New Scientist.

MORE MATERIALS NEWS: Making Building Materials Out of Fast-Growing Grasses Capture More Carbon Than Trees for US Startup

For that, they would need to test just how flexible and stretchy the material could be when subjected to the conditions of mass production. In factories that produce plastic clinging wrap, the plastic is formed into sheets by being blown into huge bubbles.

If that existing production method couldn’t be utilized as is, then the researchers would need to determine how much water and energy new methods might take.

MORE SUSTAINABILITY NEWS: Build With Compost: Researchers Turn Food Scraps Into Materials Stronger Than Concrete

Seaweed is ridiculously versatile, and countries around the world are testing it out as a material for all sorts of applications.

These diapers are made out of seaweed and are good for a baby’s skin, while Turkey and Denmark are using seaweeds like algae as a fuel for cars and planes. Scientists in Australia are using it to clear methane from cows’ stomachs, others in the Netherlands are using it to clean up harbor pollutants in Rotterdam, and a Baltic-to-Caribbean startup is harvesting invasive algae for all manner of products like packaging, foodstuffs, and cosmetics.

SHARE This Sustainable Story With Your Eco-Conscious Friends…