Bio-based polyurethane foam decomposes in seawater environment, study finds

Latest: Plastic pollution is everywhere these days. Billions of tons of waste plastic end up in landfills or float in the sea, gradually breaking down into smaller and smaller pieces but never really disappearing.
This is one of the most serious environmental problems of our time, and it will not go away unless we change our plastic usage habits or develop new materials that are biodegradable.

That’s exactly what scientists at UC San Diego have been doing for the better part of the past decade. Including biologist Stephen Mayfield and chemist Michael
Burkart and Robert “Skip”
An interdisciplinary team including Pomeroy has developed polyurethane foam made from algae and other biological sources, so the foam can be biodegraded by natural decomposers (bacteria and fungi) in the environment. Experts have used these foams to make shoes, including flip-flops, the world’s most popular footwear, and have tested their breakdown in terrestrial environments. Once buried in soil, the shoes begin to degrade in as little as 16 weeks.

Now, in the new study, the team tested whether these polyurethane foams, made from bio-based monomers, would break down when immersed in seawater. The researchers and study co-author Samantha
Collaborating with Clements, Samantha Clements is a marine biologist and research diver at Scripps Institution of Oceanography. They fixed foam and shoe samples at Ellen Browning
Scripps Memorial Pier and monitored their physical and chemical changes using Fourier Transform Infrared Spectroscopy and Scanning Electron Microscopy.

The location of the terminal provides a unique opportunity to test the material in a natural nearshore ecosystem, an environment where waste plastics often end up. In 2010, researchers estimated that 8 billion kilograms of plastic entered the ocean in one year, with a significant increase expected by 2025. When plastic waste enters the ocean, it can damage marine ecosystems, wash ashore as litter, or migrate to central locations, forming garbage vortices, such as the Pacific Garbage dump that covers an area of ​​more than 1.6 million square kilometers.

The findings, now published in the journal Environmental Science, show that those experimental polyurethane materials attached to the dock were quickly attached by various marine organisms and began to degrade in just four weeks. Decomposers, mainly bacteria and fungi, break down materials into their original monomers (chemical molecules), which are then used as a source of nutrition. When the researchers identified the microbes that were able to consume the polyurethane samples, they found that these microbes were species commonly found throughout natural marine environments.

Stephen, professor in the School of Biological Sciences and director of the California Seaweed Biotechnology Center
Mayfield said: “There is no single discipline that can solve these general environmental problems, but we have developed a comprehensive solution that works on land and now we know that biodegradation is also possible in the ocean. I am surprised to see that there are How many organisms settle on these foams. It becomes something like a microbial reef.”

The researchers will continue to seek to develop renewable and sustainable monomers made from biological sources to produce polymers for different applications in the future. Their research will also continue to investigate the process of biological breakdown and the resulting chemicals. Experts say people are starting to understand the magnitude of the plastic pollution problem and are starting to look for alternatives that are less damaging to nature.

Mayfield said: “Incorrect handling of plastic in the ocean breaks down into microplastics and has become a huge environmental issue. We have shown that it is absolutely possible to create high-performance plastic products that degrade in the ocean.
Plastic is not supposed to enter the ocean, but if it does, the material becomes food for microbes, not plastic waste and microplastics that harm aquatic life. ”