Eco-sustainable shoes that degrade in the sea after 12 weeks, breaking down into elements that nourish the microorganisms of the marine ecosystem: this is what the researchers of the University of California at San Diego have achieved, thanks to new biodegradable plastic materials based on polyurethane foams .
The result is published in the journal Science of The Total Environment.
"Improper disposal of plastic in the oceans generates microplastics and has become a huge environmental problem," says biologist Stephen Mayfield.
“We have shown that it is absolutely possible to make high-performance plastic products that can even degrade in the ocean.
Plastic shouldn't end up in the sea, but if it does, this material turns into food for microorganisms and not into plastic debris and microplastics that damage aquatic life. "
Footwear, including the hugely popular flip-flops, account for a large percentage of plastic waste that ends up in landfills and the sea.
To solve this problem, the researchers worked eight years to develop new biodegradable polymers that have been shown to break down in the soil.
To verify their behavior also at sea, some tests were conducted in collaboration with researchers from the Scripps Institution of Oceanography.
In particular, some samples were exposed to the action of waves and tides, monitoring their molecular and physical changes with infrared spectroscopy and scanning electron microscopy.
The results showed that the material started to degrade after just four weeks thanks to the
action of bacteria and fungi living in the sea.
These microorganisms colonize the shoe and break it down into elements that they use as nourishment.
"I was amazed at how many organisms colonize these foams in the ocean," comments Mayfield. "It's like a coral reef for microorganisms."