Simultaneous reduction and surface functionalization of graphene oxide and the application for rubber composites

The simultaneous reduction and functionalization of graphene oxide (GO) was realized through a chemical grafting reaction with a functionalization agent N,N-bis(3-aminopropyl)methylamine (APMEL). The reduced and functionalized reduced GO (rGO-APMEL) sheets can be well dispersed in water without any added surfactant and the formed stable rGO aqueous dispersion can be kept for a long time, which can be used for the preparation of rubber–graphene (GE) composites by latex mixing. The electrostatic interaction between rGO–APMEL (positively charged) and natural rubber latex particles (negatively charged) leads to the formation of NR/rGO–APMEL composites with strong interaction. Compared with blank NR, the tensile strength and modulus for NR/rGO–APMEL increase with the rGO–APMEL loading. Especially, when the filler content is 5 phr, the tensile strength of NR/rGO–APMEL-5 increases by 32.7%, as a control the tensile strength of NR/GO-5 and NR/rGO-5 decrease by 20.1 and 15.6%, respectively. The entanglement-bound rubber tube model was used to analyze the reinforcing effect of GE on NR/rGO–APMEL nanocomposites at a molecular level. This study may provide us a novel approach to prepare well dispersed and exfoliated rGO–polymer nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47375.