New plant-based plastics can be chemically recycled with near-perfect efficiency
Derived from plant oils, the new plastics were presented in a paper published Wednesday in Nature as low-waste, environmentally friendly replacements to the conventional fossil fuel-based plastics that enter natural ecosystems at a rate of millions of tons per year.
Most recycling performed today is mechanical recycling, in which plastic is sorted and sliced into pellets that are then used to create new plastic materials. Chemical recycling, in contrast, involves breaking down the long polymer chains of plastic with heat or solvents to retrieve the material’s initial monomer components.
One of the obstacles to developing chemical-recycling technology is also a reason why plastic is a useful material: the strong carbon-carbon bonds in its molecular structure. Polyethylene, the most common kind of plastic, requires at least 600 degrees Celsius to break those bonds to retrieve the monomers, and is chemically recycled at a rate lower than 10%.
“Stability of the hydrocarbon chains is rather a problem in that case,” said Stefan Mecking, the lead author of the study and the department chair of chemical materials science at the University of Konstanz in Germany. “To really break them down into small molecules needs high temperatures and is energy intensive, and also the yields are not that good.”
Full story by Zack Fishman at The Academic Times
