Molecular Insights into Antioxidant Efficiency of Melanin: A Sustainable Antioxidant for Natural Rubber Formulations.N-(1,3-Dimethyl butyl)-N'-phenyl-p-phenylenediamine (6-PPD) is a worldwide antioxidant commonly added to delay the thermo-oxidative degradation of tire rubbers.  Given these results, the nanocomposite (NR-MLN-SiO2) with natural antioxidant melanin manifested outstanding antioxidant properties by preferentially bagging the ROO· radicals, thus improving NR's thermal-oxidative aging relative to 6-PPD.  The MD results revealed that the intermolecular interactions at the NR/antioxidant interface benefited the antioxidant MLN to bind tightly to the NR in NR-MLN-SiO2 composite, thus exhibiting improved dispersion, O2 barrier properties, and thermo-oxidative stability, which could extend the service life of NR products (e.g., tires). 
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