To prepare the formulations based on the TPO matrix, the chamber of an internal mixer (Haake PolyLab OS) was heated to 170 °C i.e., around 20 °C above the melting temperature (Tm) of the TPO matrix. 40 g of TPO were introduced into the chamber and mixed, with a rotor speed of 50 rpm, for a few minutes, until the torque stabilization. The appropriate amount of antioxidant is then introduced, and the rotor speed is increased to 70 rpm, for 10 min, before stopping the heating and recovering the mixture. Films with a thickness of 1 mm were then produced using a hot press (LabTech Engineering Company Ltd) and 10 x 10 cm 2 molds. For that, around 13 g of polymer were first preheated for 3 min, then compressed between the plates at 170 °C and 160 bar for 8 min, and finally cooled down for 5 min at room temperature. The antioxidant activity of the synthesized molecules was quantified by DPPH assay adapted from the literature . The DPPH reagent was dissolved in methanol to give a concentration of 0.09 mM. Antioxidant solutions were prepared at different concentrations in methanol. The radical scavenging activity of the antioxidant was determined by mixing 30 µl of antioxidant solution with 3 ml of DPPH solution in a quartz vessel. The solution was agitated on a vortex mixer and placed for 24 h in the dark, to ensure complete reaction. Sample absorbance was measured at 517 nm using a Shimadzu UV 2600 spectrometer. A blank was run in a quartz cell containing methanol. The percentage of DPPH trapping activity was calculated using Equation . (1)