Together, they account for more than half of all thermoplastics produced. They stand out for their excellent performance, with a wide range of mechanical and thermal properties, good chemical resistance, and an easy processing. However, if not formulated, these neat polymers could not be so widely used alone. This is because the long carbon chains of TPO or the long polyol part of TPU are sensitive to thermo-oxidative degradation, particularly when subjected to thermomechanical treatment with oxygen, light or heat, mainly during processing, but also during their lifetime . Oxidative degradation of polymers is initiated by the formation of free radicals on the polymer chain due to the breaking of carbon bonds. These free radicals then react with oxygen present in the air, initiating an autocatalyzed reaction that will ultimately generate chain breakdowns, resulting in a loss of polymer properties .