Enhanced electrical conductivity and mechanical property of SBS/graphene nanocomposite

摘要

Styrene-butadiene-styrene tri-block copolymer/ graphene (SBS/GE) nanocomposites were prepared by solution mixing and in situ reduction of graphene oxide using hydrazine hydrate. The dispersion state of graphene was examined by XRD and optical examination, which indicates that the graphene nanosheets are well exfoliated and dispersed in the SBS matrix. The interfacial interaction between graphene and SBS was investigated by sedimentation experiment in toluene. After dissolving of the SBS/GE nanocomposite, the graphene nanosheets do not separate from the solution, moreover, even after prolonged ultracentrifugation, a dark-colored supernatant with graphene suspension is still retained, suggesting that the graphene nanosheets are stabilized in the solution with the attached SBS molecules due to the existence of strong interfacial interaction. The well dispersion of graphene and the enhanced interfacial interaction lead to a remarkable improvement in the electrical conductivity and mechanical properties. A percolation threshold as low as 0.12 vol.% of graphene has been achieved because of the formation of a three dimensional conductive network. Meanwhile, with the incorporation of as low as 0.5 wt% of graphene, the tensile strength of the nanocomposite has already displayed a two-fold increase compared with that of pure SBS.