Most PE products are discarded in landfills after a single use. They also end up in the environment, polluting oceans and endangering marine ecosystems. Two chemical engineering faculty researchers at UMass Lowell, Associate Professor Dongming Xie and Hsi-Wu Wong, are trying to change that. Supported by a three-year, $463,000 grant from the National Science Foundation, they are developing technology that would help reduce waste PE through upcycling, a process in which discarded materials are converted into products of higher value than the original. “Waste PE accounts for more than 50% of the world’s plastics waste stream,” says Xie, who is the project’s principal investigator. “PE’s projected annual manufacturing growth rate of 12%, combined with the lack of effective recycling options, makes PE a major environmental concern.”
According to Xie, current recycling and upcycling methods used for waste PE, such as mechanical shredding, thermochemical treatment and biochemical conversion, all result in low product qualities, inefficient conversion rates to value-added products and high processing costs. “None of the existing PE recycling or upcycling methods alone will likely contribute to a circular economy for plastics,” notes Wong.
Circular economy is a relatively new concept in sustainability and innovation. Rather than the usual practice of plastics being used once and discarded, plastic materials in a circular economy constantly flow around a “closed loop” system, retaining their value and prolonging their useful life through repeated reuse, repair and recycling. The materials are discarded only as a last resort. Wong estimates that nearly 100 million tons of Earth-warming greenhouse gases are emitted into the atmosphere annually from waste PE.