Recycled from waste tires carbon black/high‐density polyethylene composite: Multi‐scale mechanical properties and polymer aging

Abstract This study addresses the global issue of recycling vehicle rubbish tires by a vacuum pyrolysis process, exploring a novel environmentally responsive approach for thermal decomposition and recovery of the carbon black particles contained in tires (25–30 wt%). Carbon black is typically used for its UV protection in plastics and abrasion resistance in composites and rubbers. This research aims at providing an eco‐responsible alternative to commercial carbon black of fossil origin by recycling the carbon black (rCB) from end‐of‐life tires. A particle reinforced composite material was developed containing rCB and high‐density polyethylene. For comparison purposes, an identical composite was manufactured using commercial carbon black (CB). Accelerated aging studies have been carried out on the materials. Topographic evolution of the samples with aging and oxidation kinetic of the surface and through the thickness were studied. Multiscale mechanical properties have been evaluated for a more comprehensive understanding of the mechanisms involved in the degradation. A comparison of the different materials properties was carried out in order to highlight the various elements linked to the degradation and UV protection of materials. This work helps demonstrating the feasibility of using recycled carbon black particles from waste tires as a high‐performance filler for plastics and composites. Highlights Recycled carbon black (rCB) is an eco approach of revalorizing tire waste. Vacuum pyrolysis successfully allows recovery of reusable rCB. The rCB acts as a photon absorber, limiting degradation of HDPE. The rCB limits the cross‐linking responsible of embrittlement of HDPE. A critical carbonyl index of 20 marks the occurrence of cracks and degradation.