Ground lemon and stevia leaves as renewable functional fillers with antioxidant activity for high-density polyethylene composites

Abstract The development of new sustainable material solutions in the processing thermoplastic polymers concerns both application biopolymers and use valorized plant derivatives as fillers modifiers petrochemical polymers. Herein, possibility using unprocessed raw parts two commonly used food industry leaves, i.e., lemon (LL) stevia (ST), active functional for high-density polyethylene (HDPE) has been verified. series composites containing 1, 2, 5 wt% ground leaves produced melt-mixing process were analyzed thermal properties (DSC TGA), antioxidant potential was evaluated. Verifying effect on resistance to oxidation molten state carried out by oxygen induction time (OIT DSC) analysis oscillatory rheology under steady-state shear conditions combined with spectroscopic (FTIR) carbonyl index (CI) analysis. Studies have shown that introduction types allows a significant increase melt (above 2 times longer OIT concerning HDPE, ~ 35 min) without substantial changes their crystalline structure stability. Determined after long-term rheological measurements an oxidative atmosphere CI showed 70 82% lower values LL ST compared unmodified polyethylene. Graphical abstract