Thermoplastic SEBS Elastomer Nanocomposites Reinforced with Functionalized Graphene Dispersions

Blending a maleinated polystyrene-b-poly(ethylene-r-butylene)-b-polystyrene (SEBS) thermoplastic elastomer with functionalized graphene (FG) dispersions in tetrahydrofuran (THF) prior to the melt processing results in SEBS/FG nanocomposites with improved property profiles. According to microscopic imaging (atomic force microscopy, transmission electron microscopy, focus ion beam–scanning electron microscopy), FG dispersions derived from multilayer graphene (MLG 350) and thermally reduced graphite oxide enable uniform dispersion of single- and few-layer FG within both the THF and the SEBS matrix. In contrast, high-pressure homogenization of nonfunctionalized graphite yields larger graphene stacks together with blend of graphene stacks with micrometer-sized graphite (GG). As opposed to SEBS/GG composites, SEBS/FG composites exhibit superior mechanical properties as well as higher Shore A hardness, electrical conductivity at a lower percolation threshold, and enhanced gas barrier resistance. Hence, SEBS/FG composites hold promise as thermoplastic elastomers, serving the needs of automotive and sealant industries.