Naphthylhydrazone-based imines as a multifunctional regulator for rubber composites with superior dynamic performance and thermo-oxidative resistance

Carbon black (CB), as one of the most widely used reinforcements for rubbers, can integrally improves the processability and static/dynamic mechanical properties of rubber. Nevertheless, the dispersion state of CB and the interfacial adhesion in the composites are generally subject to the significant difference in surface energy between these two components, which leads to external hysteresis loss and hence compromises the lifetime of the products. In this study, naphthylhydrazone-based imine (HZO) was used as a feasible interfacial regulator for rubber/CB composites, since the naphthylhydrazone moiety can efficiently capture and stabilize the macroradicals generated by the rupture of rubber chains during the mixing process and then transferred to the surface energy trap of CB through the charge-sharing effect. Accordingly, the interfacial adhesion and dispersion state of the CB particles in the composites can be remarkably enhanced. Incorporating only 1 phr (parts per hundred of rubber) HZO can enable substantial decreases of approximately 11 °C in heat generation and 22 % in energy loss to the composites under dynamic loading. Besides, due to its excellent radical-trapping capacity, HZO can effectively scavenge the reactive radicals generated during the thermo-oxidation process, which considerably enhances the aging resistance of the resulting samples. We envisage that the as-prepared HZO with radical-trapping capacity can open up a practical methodology to achieve efficient interfacial regulation of rubber/CB composites, which has significant potential in the preparation of energy-saving and aging-resistant tire products.