Scientists at the U.S. Department of Energy’s Ames Laboratory and their partners from Clemson University have discovered a green, low-energy process to break down polystyrene, a type of plastic that is widely used in foam packaging materials, disposable food containers, cutlery, and many other applications.
Polystyrene is part of a much larger global plastic waste problem. Hundreds of millions metric tons of polymers are produced each year, a large majority of which is discarded after use. Due to the chemical stability and durability of industrial polymers, plastic waste does not easily degrade in landfills and is often burned, which produces carbon dioxide and other hazardous gases. In order to stop the growing flood of polymer waste and reduce carbon dioxide emissions, plastics have to be recycled or converted into new value-added products.
Currently, recycling of the vast majority of plastics is not economically feasible; their sorting and separation are time and labor intensive, while chemical processing and remanufacturing requires a significant energy input and toxic solvents. Re-processed polymers often show inferior performance to that of the freshly manufactured “made from scratch” materials.
A team of scientists at Ames Laboratory used processing by ball-milling to deconstruct commercial polystyrene in a single step, at room temperature, in ambient atmosphere in the absence of harmful solvents. Ball-milling is a technique that places materials in a milling vial with metal ball bearings which is then agitated until a desired chemical reaction occurs. Called mechanochemistry, this experimental approach has numerous applications in new materials synthesis, and attractive features where plastics recycling is concerned.
Read more at DOE/Ames Laboratory
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