Study enables efficient, selective chemical recycling of polymer mixtures

A new study from the teams of SCHEMA Director Prof Charlotte K. Williams at the University of Oxford and SCHEMA Digital & Information Technologies Lead Prof Antoine Buchard from the Green Chemistry Centre of Excellence at the University of York has revealed a general link between the structure of polymers and the rate at which they can be depolymerised back to their pure monomers.

This new fundamental insight allows us to identify the lowest-energy conditions resulting in the fast recycling of polymers into monomers, with minimised catalyst loading. It also reveals the appropriate temperatures to selectively separate structurally similar polymer mixtures by recycling them back into their pure monomers.

The study, sponsored by the Royal Society, the EPSRC UK Catalysis Hub and SCHEMA focused on polyesters and polycarbonates made from cyclic esters and carbonates. These materials are particularly interesting as several monomers are already commercialised and biobased, and their properties match those of conventional hydrocarbon polymers.

First author, Dr Thomas McGuire, explains the significance of the research: "This study is important because it provides a framework for how to design next-generation polymeric materials with end-of-life recyclability in mind. The chemistry may also be applied to the separation of very similar polymer blends, which is a long-standing challenge in material recycling".

The study was published in the Journal of the American Chemical Society (JACS) and can be found here: https://doi.org/10.1021/jacs.5c04603