Evaluation of the effectiveness of black tea leaves wastes as phytochemical-rich plant fillers and natural antioxidant in polyethylene

The aim of this study is to compare the structure as well as the mechanical and thermomechanical properties of polyethylene stabilized with a petrochemical additive (Irganox 1010) and a sustainable alternative, antioxidant-rich black tea waste leaves (BTW). The influence of both stabilizers was evaluated for samples produced by compression, injection, and rotational molding (CM, INM, and RM). The polymer matrix used was low-density polyethylene LDPE SBC 818 I’m Green ® (Braskem), modified with 5 wt% BTW and an equivalent amount of Irganox 1010 based on the total phenolic content in BTW. Stabilization efficiency was assessed using Fourier transform infrared spectroscopy (FTIR) and calorimetric techniques, including oxidation induction time (OIT) and oxidation onset temperature (OOT), both measured by differential scanning calorimetry (DSC). Additionally, porosity, mechanical performance in static tensile testing, and Vicat softening temperature (VST) were determined to provide a comprehensive comparison of the stabilization systems.