Epilogue: Sorting, Depolymerizing, and Recycling Polymers: The Long Road to a Circular Plastics Economy

Abstract After Hermann Staudinger laid the foundations of polymer science 100 years ago, an extraordinary scientific, technological, and industrial saga has been written by a long list of academic and industrial scientists. As a result, polymers are present in practically all sectors of human activity, transforming human societies in terms of quality of life, safety, hygiene, etc. Yet the expansion in the production and use of polymeric materials comes at a price for the environment because the polymer economy has been organized since its inception under the “ take, make, dispose ” pattern. Such a linear organization of the polymer economy causes considerable damages to the environment, wastes resources, and harms wildlife. This article discusses the steps that need to be taken worldwide to turn a still linear polymer economy into a circular one. Questions such as the sorting of polymer waste, their mechanical recycling, their recycling through nonchemical processes, the depolymerization of some polymers into monomers, the pyrolysis of nondegradable polymers, the potential of biodegradation processes are critically reviewed. Recommendations are made in this article to dramatically reduce the carbon footprint of the whole production chain from monomer synthesis to the manufacture of polymers and build a truly circular polymer economy with reuse, repair, and recycle as its foundations.