Preparation and reinforcement performance of RGO-CNTs-SiO2 three-phase filler for rubber composites

Rubber reinforcement technology is developing towards the direction of high efficiency and multi-functionality, and the reinforcement of rubber by a single-component filler can no longer meet the requirements. Nanocomposite fillers have become the development trend of high-performance reinforcing fillers due to the complementary advantages and synergistic reinforcing effects of each component. Reduced graphene oxide-carbon nanotubes (RGO-CNTs) composites were prepared by a method of electrostatic assembly. The non-covalent modified RGO-CNTs was used as a substance to grow in situ SiO2 nanoparticles (RGO-CNTs-SiO2), and the RGO-CNTs-SiO2 three-phase fillers were obtained. The RGO-CNTs-SiO2 three-phase fillers were further used to study the reinforcing properties of hydrogenated nitrile rubber (HNBR). Furthermore, the effects of RGO-CNTs-SiO2 with different component contents on the reinforcing properties of HNBR were systematically studied. The TEM images of RGO-CNTs-SiO2 show that the RGO and CNTs promotes mutual dispersion, and the SiO2 nanoparticles (average diameter 7 nm) are highly dispersed on the surface of RGO-CNTs. The characterization of RGO-CNTs-SiO2/HNBR indicates that the RGO-CNTs-SiO2 efficiently weaken the filler network and improve the filler-rubber interaction. The results show that the three-phase fillers produce obvious synergistic reinforcing effects. The highest tensile strength (30.1 MPa) of RGO-CNTs-SiO2/HNBR is achieved at the RGO:CNTs mass ratio of 1:5, the RGO-CNTs mass percentage of 2%, and the filler loading of 50 phr. This work demonstrates the considerable promise for developing three-phase filler-based rubber composites.