Recycled Carbon Black/High-Density Polyethylene Composite from Waste Tires: Manufacturing, Testing, and Aging Characterization

This study addresses the global issue of recycling used vehicle tires, typically burned out or trimmed to be reused in playground floors or road banks. In this study, we explore a novel environmentally responsive approach to decomposing and recovering the carbon black particles contained in tires (25-30 wt.%) by vacuum pyrolysis. Given that carbon black is well known for its UV protection in plastics, the objective of this research is to provide an ecological alternative to commercial carbon black of fossil origin by recycling the carbon black (rCB) from used tires. In our research, we create a composite material using rCB and high-density polyethylene (HDPE). In this article, we present the environmental aging studies carried out on this composite material. The topographic evolution of the samples with aging and the oxidation kinetics of the surface and through the thickness were studied. The Beer-Lambert law is used to relate the oxidative index to the characteristic depth of the samples. The UV photons are observed to penetrate up to 54% less with the addition of 6 wt.% of rCB compared to virgin HDPE. In this work, the addition of rCB as filler for HDPE used for outdoor applications has demonstrated to be an antioxidant for UV protection and a good substitute for commercial carbon black for industrial goods.