Patent ID: 11912840
Assignee: VERSALIS S.P.A.
Field: Macromolecular chemistry, polymers (Chemistry)
Classification: CPC C  B | IPC B  C

Claim 0:
1. A composition, comprising:
a solvent having an interfacial tension different from that of graphite material and comprising 10 to 70% by weight of a polystyrene and 20 to 80% by weight of a styrene monomer, and
graphene and graphene nanoplatelets (GRS) stably dispersed without any evident formations of deposits or separated phases for at least 30 days in the solvent in a mass concentration of 0.05 to 5% by weight,, wherein the composition is produced by a process comprising
combining a graphite and a styrene monomer to form a mixture;
subjecting the mixture to ultrasound treatment to exfoliate the graphite to graphene and to simultaneously polymerize the styrene monomer to form a polystyrene, and
decanting or separating by centrifugation the produced mixture comprising the polystyrene, the exfoliated graphene, unpolymerized styrene and non-exfoliated graphite to remove the graphite not completely exfoliated,, wherein the ultrasound treatment is conducted at a frequency spectrum ranging from 18 kHz to 20 kHz and an ultrasound power of 60 to 110 W/cm3 in a degassed environment at a pressure of from 12 to 25 bar absolute and at a temperature ranging from 20° C. to 200° C. for 0.5 seconds to 5 minutes; and
wherein the graphene and the graphene nanoplatelets have an average thickness higher than or equal to the thickness of a single graphene layer up to 50 nm, the thickness being measured on samples of graphene and graphene nanoplatelets deposited on a silicon wafer coated with silicon oxide, with intermittent contact atomic force microscopy, called AFM tapping mode.