NOVELTY - Master batch composition comprises a polymer and at least 15 wt.% of graphene.    USE - The master batch composition is useful for making a polymer nanocomposite (claimed), which is useful: as electrical shielding material; for printed wiring in batteries and photoelectric devices (solar cells); and for producing rubber for tires.    ADVANTAGE - The master batch composition provides the polymer nanocomposite having high degree of exfoliation and dispersion of graphene nanoplatelets within the polymer matrix.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a polymer nanocomposite comprising a polymer and graphene produced by providing the master batch composition and mixing some or all of the master batch with a polymer to provide the polymer nanocomposite;    (2) making the master batch composition, comprising mixing a slurry of graphene in a solvent system with a polymer, and removing the solvent system to produce a master batch comprising 15-60% graphene;    (3) making a graphene/polymer (poly(vinylpyrrolidone)) master batch, comprising concentrating a solution or stable dispersion of exfoliated graphene above the solubility and stable dispersion limit of the exfoliated graphene, dissolving poly(vinylpyrrolidone) in the graphene/solvent slurry in a ratio of 1:1-1:10 graphene to poly(vinylpyrrolidone), and removing the solvent with continuous mixing to isolate the resultant graphene/poly(vinylpyrrolidone) master batch as a solid;    (4) a graphene/polymer master batch composition comprising a thermoplastic polymer comprising greater than 20 wt.% of highly dispersed and exfoliated pristine graphene nanoplatelets such that the average thickness of the nanoplatelets does not exceed 5 atomic layers, where a minimum of 10% of the nanoplatelets are single atomic layer graphene, and the oxygen content of the graphene is less than 1%; and    (5) making graphene/polymer master batch, comprising exfoliating graphene in a polymerizable solvent to provide a dispersion of exfoliated graphene in the polymerizable solvent and polymerizing the polymerizable solvent to produce the graphene/polymer master batch.