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.