Characterization of aging of a new composite made of HDPE and recycled carbon black from endof-life tires

Tropical climate conditions are extremely aggressive and are the primary cause of polymers degradation affecting their durability. Carbon black is a filler used from protecting polymers from UV radiation. However, commercial carbon black is a fossil product, and the tire industry is the one that uses it the most (70% of total production in the USA), a tire containing 25-30 wt.% of carbon black. About one billion of tires are manufactured and disposed worldwide each year, and this is constantly increasing, and so the risk of ecological disaster. It is therefore critical to develop solutions for recycling and recovery of this waste. Pyrolysis is an ecological solution that allows to recover the original products entering in the tire composition: liquid and gaseous hydrocarbons and carbon black. The recovered carbon black can be reuse as a filler and is an alternative to the commercial carbon black. In this study composites are made of recycled carbon black (rCB) issued from waste tires pyrolysis and high-density polyethylene (HDPE) and are submitted to accelerating aging conditions (UV, humidity, temperature). The rCB acts as UV protector, showing improvement of the resistance of the polymer to oxidation and a reduction of crazing propagation. The oxidation was also studied through the thickness of the samples. A Beer-Lambert law was used to link the oxidative index to the characteristic depth. The rCB acts as a photon absorber and a trap for the propagation of radicals during oxidation, limiting the action of photons in the thickness