Chemocatalytic recycling of polyethylene and polyvinylchloride using colloidal metal nanoparticles and homogeneous catalysts

Plastics have become an essential part of modern society, as versatile and cheap materials in many applications. Unfortunately, their success inevitably leads to large amounts of plastic waste, which could form a feedstock in a circular economy. However, there is a lack of new concepts that allow to process these materials into new building blocks.
In this project, innovative chemical routes are explored for recycling two common plastics, viz. polyethylene (PE) and polyvinyl chloride (PVC). By using thermostable catalytic systems, we propose to transform these polymers into partially unsaturated hydrocarbon chains. For the specific case of PE, we will develop new metal nanocatalysts for the transfer hydrogenation of PE to ethylene. For PVC, we will use stable ionic liquids as catalytic solvent for removing HCl; simultaneously, we will also use hydrogen to remove part of the HCl in a metal catalyzed hydrogenolysis. Using advanced NMR techniques, we will follow whether the polymers fully dissolve during this upgrading, and whether the catalysts can approach the polymer chains to a sufficient degree. Finally, we will split the partially dehydrogenated hydrocarbon chains, in a process called metathetic ethenolysis. The ambitions of the project are twofold: (i) we will open routes to high value building blocks with double bonds at both ends of the chain; (ii) we will gather new insights as to how homogeneous and nanoparticulate catalysts can function in upgrading polymer wastes.