Rational Design of Graphene Surface Chemistry for High-Performance Rubber/Graphene Composites

Abstract

In a rubber/filler composite, the surface chemistry of the filler is a critical factor in determining the properties of the composite because it affects the dispersion of the filler and the interfacial adhesion between the filler and rubber. In this study, we primarily focus on how graphene surface chemistry affects the dispersion of graphene and interfacial adhesion in butadiene− styrene rubber (SBR)/graphene composites and on the resultant properties of the composites. Composites that contain graphene with tailored surface chemistry are prepared via the chemical reduction of graphene oxide (GO) in situ. Subsequently, the dispersion of the graphene and interfacial adhesion are fully investigated in relation to the graphene surface chemistry. As revealed by dielectric relaxation spectroscopy, the bulk segmental relaxation is independent of the graphene surface chemistry, whereas the interfacial relaxation mode is retarded in the composite with stronger graphene−rubber affinity. The contribution of the graphene surface chemistry to the dispersion of the graphene and interfacial adhesion is quantified by calculating the surface energies. The results indicate that, when the CO x fraction in the graphene is greater than 0.2, it exerts an increasingly strong effect on the dispersion of the graphene; in contrast, when the CO x fraction is less than 0.2, it exerts a significant and positive effect on the interfacial interaction. In particular, on the basis of the surface energy analysis, quantitative predictors for the dispersion of graphene and interfacial adhesion are presented; these predictors can be used for the virtual design of graphene surface chemistry to optimize the properties of composites.

Natural rubber/graphene oxide composites: Effect of sheet size on mechanical properties and strain-induced crystallization behavior

“…The decrease of tan % peak reflects that GO sheets have effectively immobilized NR chains near the polymer-particle interface due to favorable interfacial interactions with the NR matrix [39,57]. Meanwhile, the maximum tan % values of the composites with G2 and G1 are lower than that of G3.…”

Transport performance in novel elastomer nanocomposites: Mechanism, design and control

“…In addition, the reduction of GO can be performed in the coagulated rubber/GO compounds. The aggregation of graphene is significantly limited during reduction because the GO has already been immobilized by the rubber chains in the compounds [7,103].…”

“…(3) Elastomers are thermosetting polymers. The dispersion and aggregation of fillers is dependent on interfacial interactions and heat/pressure that facilitate the thermodynamically driven aggregation of the conductive fillers [7,8]. The processing of rubbers differs from the thermoforming process of plastics because the former is accompanied by crosslinking.…”

Graphene/elastomer nanocomposites

“…an increase in the Young's modulus or stress at break) are desirable, then the route of vulcanization should be followed. On the other hand, if high electrical conductivity values are the main objective, uncrosslinked materials can exhibit a very low percolation threshold and high conductivity values.Tang et al[207] have also shown recently the importance of the surface chemistry of the filler in controlling both the dispersion and interfacial adhesion between graphene produced by the in situ chemical reduction of GO and styrene/butadiene rubber, both of which affect the resultant properties of the nanocomposite. The determinant factor on the dispersion of graphene, according to their work, is the CO x fraction.…”