UC San Diego scientists have utilized an algae oil formulation to create biodegradable polyurethane foams for the shoe manufacturing industry.
Developed in collaboration with startup company Algenesis Materials, these new sustainable, consumer-ready materials meet the commercial specifications for midsole shoes and the foot-bed of flip-flops.
Flip-flops are ubiquitous everywhere and they account for a troubling percentage of plastic waste that ends up in landfills, on seashores and in our oceans.
The UC San Diego team has been working on resolving this problem for years, and has now taken a step farther toward accomplishing this mission.
The project was co-led by graduate student Natasha Gunawan from the labs of professors Michael Burkart and Stephen Mayfield, and by Marissa Tessman from Algenesis.
In addition to devising the right formulation for the commercial-quality foams, the researchers worked with Algenesis to not only make the shoes, but to degrade them as well.
Commercial products like polyesters, bioplastics (PLA) and fossil-fuel plastics (PET) can biodegrade, but only in the context of lab tests or industrial composting, explains Mayfield.
Putting their customized foams to the test by immersing them in traditional compost and soil, the UC San Diego team discovered the materials degraded after just 16 weeks.
During the decomposition period, the scientists measured every molecule shed from the biodegradable materials for any form of toxicity.
They also identified the organisms that degraded the foams.
“We took the enzymes from the organisms degrading the foams and showed that we could use them to depolymerize these polyurethane products, and then identified the intermediate steps that take place in the process,” notes Mayfield.
“We then showed that we could isolate the depolymerized products and use those to synthesize new polyurethane monomers, completing a ‘bioloop.'”
This full recyclability of commercial products is the next step in the scientist’s ongoing mission to address the current production and waste management problems we face with plastics – which if not addressed, will result in 96 billion tons of plastic in landfills or the natural environment by 2050.
“The life of material should be proportional to the life of the product,” opines Mayfield.
“We don’t need material that sits around for 500 years on a product that you will only use for a year or two.”
Image and content: Tamba Budiarsana-Pexels/UC San Diego