Innovative Recycling of Cross‐Linked Polyethylene: Regeneration by Flash Reactive Extrusion and Reincorporation for Enhanced Circularity

ABSTRACT Cross‐linked polyethylene (XLPE), widely utilized in electrical cables for example, remains a challenging material to recycle. While thermo‐mechanical devulcanization has been extensively studied for rubber recycling, its application in regenerating XLPE still requires an in‐depth investigation of the correlation between process parameters and ultimate material properties. Here, XLPE waste was regenerated by flash extrusion at high temperatures and shear. A thorough characterization of the so‐obtained polyolefins (rXLPEs), including gel content and chemical analyses such as NMR and SEC afforded a comprehensive picture of the mechanisms involved in the regeneration process—namely chain scission or chain branching—depending on the extrusion temperature. We address viscoelastic properties combining extensional and shear rheology finally establishing distinct relationships between polymer molecular structure and rheological behaviors. Moreover, when rXLPEs are reincorporated into virgin linear polyethylene (20% wt. of rXLPE), the resulting blends acquire unique and individual features. Depending on the regeneration temperature of rXLPEs, the blends exhibit different processability under high shear conditions comparable to industrial continuous processing as well as a wide range of elongational and shear viscosity. This exploration in rXLPE performances offers a novel insight into a regeneration process easily extendable at large scale, paving innovative ways for applications on cable waste.