A team from the University of California, Berkley, have developed a new method to make plastics truly compostable. The modified plastic breaks down in less time using just heat and water. (Photo from University of California)
A little shining hope on this Earth Day. Is it just me, or are the sides of roads these days packed with plastic bottles and such? Imagine if all that garbage was made from this…
Despite regulations and efforts to reduce waste, single-use plastics continue to be a significant environmental problem. Biodegradable plastics are meant to be a solution to the problem, but most compostable plastic bags, lids, and cups don't break down during typical composting and can even contaminate other recyclable plastics. A team from the University of California, Berkley, have developed a new way to break these plastics down using just water and heat.
The team has embedded polyester-easting enzymes in plastic made of polylactic acid (PLA) and polycaprolactone (PCL). To protect the enzyme and prevent it from untangling, they are covered in a simple polymer wrapping. When exposed to heat and water, the enzymes have the ability to degrade the plastic and turn it into a lactic acid, which can feed microbes in the soil. The polymer wrapper also degrades.
Under industrial composting conditions, the PLA degraded within six days at 122°F (50°C), while the PCL degraded in two days at 104°F (40°C). Using this method, these plastics can biodegrade up to 98 percent of the plastic into small molecules and won't leave behind any microplastics. The modified polyester also won't break down at low temperatures or brief periods of dampness.
"People are now prepared to move into biodegradable polymers for single-use plastics, but if it turns out that it creates more problems than it's worth, then the policy might revert back," senior author Professor Ting Xu said in a statement. "We are basically saying that we are on the right track. We can solve this continuing problem of single-use plastics not being biodegradable."
With promising results, the team is now looking into how to apply this method to other plastics. The next steps include working on having more control on the level of biodegradability to allow the plastic to partially biodegrade, so the rest can be recycled into new plastic. The team believes this new method could be used to recycle various things, such as using biodegradable glue to build computers that can dissolve so the parts can be reused.
"It is good for millennials to think about this and start a conversation that will change the way we interface with Earth," Xu said. "Look at all the wasted stuff we throw away: clothing, shoes, electronics like cellphones and computers. We are taking things from the earth at a faster rate than we can return them. Don't go back to Earth to mine for these materials, but mine whatever you have, and then convert it to something else."
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