According to a 2020 study, the United States produces more plastic waste than any other country - about 46.3 million tons - or 287 pounds per person per year.
The country's 9% recovery rate will never keep up. Why is it so low? The chemical properties of plastics today make them the most difficult to recycle. Even meltable thermoplastics weaken with each reuse. This leads to the real obstacle to recycling - the economy. Just no profit incentive.
But now, a team of chemists at the University of North Carolina at Chapel Hill has reversed the situation. They have found a way to decompose plastic and make a new material stronger and stronger than before - which means it may be more valuable.
"Our approach sees plastic waste as a potentially valuable resource for the production of new molecules and materials," said Frank leibfarth, an assistant professor of chemistry at the UNC School of Arts and Sciences "We hope this method will promote the economic incentive of recycling plastics and really turn waste into treasure."
Erik Alexanian, Professor leibfarth and UNC Chapel Hill, who specializes in chemical synthesis, described in the journal Science how to close the plastic recycling cycle.
Hydrocarbon bond is one of the strongest chemical bonds in nature. Their stability makes it difficult to convert natural products into drugs, and it is difficult to recycle commercial plastics.
However, by modifying the common hydrocarbon bonds in polymers, that is, the basic components of modern plastics used in food bags, water bottles and water bottles, food packaging, auto parts and toys, the life of polymers can be extended beyond disposable plastics.
With the help of a newly discovered reagent that can peel hydrogen atoms from drug compounds and polymers, UNC chemists can form new bonds where they were previously thought not to react.
"The versatility of our method is that it can achieve many valuable hydrocarbon bond conversions on such a wide range of important compounds," Alexanian said.
Turn waste into treasure
Leibfarth group in Carolina focuses on designing smarter, more practical and more sustainable polymers.
With the support of NC policy collaboration, the team developed a super absorbent polymer that can remove dangerous chemicals from drinking water.
The researchers envision using this innovative approach to help convert difficult to recycle plastic waste into high-value polymers.
They start with plastic foam packaging used to protect electronic products during transportation, otherwise they will eventually be burying. The sample for post consumption bubbles is provided by High Cube LLC, a recycling company in Durham, North Carolina. The foam is made from low density plastics called commercial polyolefin.
By selectively extracting hydrogen atoms from polyolefins, chemists have come up with a way to extend the service life of disposable plastics into a high-value plastic called ionomer. A popular ionomer is Dow's Surlyn, which is the preferred material for various food packaging.
Most recycled plastics are "degraded and recycled" into lower quality products, such as carpets or polyester clothing, which may still end up in landfills. If turtles mistake marine plastic for food, the plastic discarded in waterways can endanger marine life.
But if the chemical can be applied repeatedly to polymers to help recycle them again and again, "it may change the way we look at plastics," leibfarth said.
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