The Tisch University Chemistry and Chemical Biology professor Geoffrey Coates and his team has worked with a group of researchers from the University of Minnesota to develop a tetrablock polymer additive that they say could greatly reduce packaging waste. Their work was funded by a branch of the National Science Foundation and was recently published in Science, Lab Manager reports.
Polyethylene (PE) and polypropylene (PP) cannot be repurposed together as they feature different chemical structures. These two constitute about two-thirds of the world’s plastics. The researchers have added a new multiblock polymer to a mix of the two incompatible materials for creating new and mechanically tough polymer.
The new polymer has been created by adding a miniscule amount of newly developed tetrablock (four-block) polymer to the alternating polyethylene and polypropylene segments. It has enhanced strength than diblock (two-block) polymers they tested.
The implications of bringing this to scale could be very big for global recycling efforts. According to the Ellen MacArthur Foundation, most of the 78 million metric tons of plastic packaging is not recycled into new products. About 40% is landfilled, 14% is incinerated and 32% leaks into waterways. Much of the remaining plastic material that is collected for recycling is either lost to processing waste or isn't viable for continued use once it reenters the recycling process.
Their work is detailed in a paper, “Combining polyethylene and polypropylene: Enhanced performance with PE/iPP multiblock polymers,” published online Feb. 23 in Science.