Environment

Algae-based, biodegradable flip flops are built to go the distance

Algae-based, biodegradable fli...
Scientists at University of California San Diego have used algae oil to produce biodegradable flip flops
Scientists at University of California San Diego have used algae oil to produce biodegradable flip flops
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Scientists at University of California San Diego have used algae oil to produce biodegradable flip flops
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Scientists at University of California San Diego have used algae oil to produce biodegradable flip flops
The team investigated many recipes for its biodegradable foam
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Researchers investigated many recipes for their biodegradable foam based on algae oil

The petroleum polymers used in construction of flip flops are critical to the durability and comfort of the immensely popular footwear, but are a huge contributor to our plastic pollution problem as they take a long time to break down once discarded. A team at the University of California San Diego has been working on a solution to this problem and is now showing off a pair of algae-based flip flops that make the grade for commercial footwear, but degrade in the environment in just 16 weeks.

The breakthrough centers on a new type of polyurethane foam made from algae oil and follows years of experimentation, with the team continually tweaking the combination of natural and synthetic components. Weighing up the need to produce a durable product that meets commercial standards for footwear against the ability to degrade in the environment was a long and arduous process, but the scientists now believe they have landed on the perfect recipe.

“The paper shows that we have commercial-quality foams that biodegrade in the natural environment,” says study author Stephen Mayfield. “After hundreds of formulations, we finally achieved one that met commercial specifications. These foams are 52 percent biocontent – eventually we’ll get to 100 percent.”

Not only did the commercial-grade foam meet the standards required of midsole shoes and the foot-bed of flip flops, but did so while having a far shorter lifespan in the environment than traditional materials. The researchers worked with material science startup Algenesis to turn the algae-based foam into flip flops and then to test how long the material took to break down.

The team investigated many recipes for its biodegradable foam
Researchers investigated many recipes for their biodegradable foam based on algae oil

This round of experiments involved placing the foam in traditional compost and soil, in which it degraded after 16 weeks. The team tracked the molecules the material shed throughout this process to ensure it had no toxic effects on the soil, and they were also able to identify the organisms that were driving the process.

“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,” says Mayfield. “We then showed that we could isolate the depolymerized products and use those to synthesize new polyurethane monomers, completing a ‘bioloop.’”

This opens to the door to not just more eco-friendly flip-flops, but a new type of plastic product that is fully recyclable. The researchers say they are on track for commercial production, but first need to work through the economical side of things with their manufacturing partners.

“The life of material should be proportional to the life of the product,” says 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.”

A paper describing the research was published in the journal Bioresource Technology Reports.

Source: University of California San Diego

2 comments
paul314
How long do they last in use? Ordinary flip-flop soles can last for years if they don't get lost or outgrown.
D[]
Questioning whether or not plastic/rubber flip-flops are truly a "huge contributor" to the plastic waste issue. If these last 1/2 as long as my cheap "locals" there is no real benefit. If they last 1/10th as long (more realistic as my rubber ones last a couple of years of nearly daily use) then they make the waste problem worse and become a 'huger contributor'.