▎ 摘　　要

NOVELTY - Producing pristine graphene nanoplatelets having a carbon/oxygen ratio of greater than or equal to 100:1, comprises: (a) expanding flakes of intercalated graphite having a carbon/oxygen ratio of greater than or equal to 100:1 and a lateral size of less than or equal to 500 mu m by exposing the flakes to 1300-12000 degrees C for less than 2 seconds, where expanded graphite has carbon/oxygen ratio of greater than or equal to 100:1; (b) dispersing obtained expanded graphite in water in absence of a surfactant or in presence of a surfactant in an amount of less than 1 wt.% the graphite; and (c) subjecting the obtained aqueous dispersion to exfoliation and size reduction treatment. USE - The process is useful for producing pristine graphene nanoplatelets (claimed), which are useful as additives or components of: elastomeric compositions for tires; paints and silicone compositions; and compositions for treating articles such as textiles. ADVANTAGE - The process provides the pristine graphene nanoplatelets, which: can be produced in a continuous way with low energy consumption; are free of surfactant or comprise less than 1 wt.% surfactant (claimed) and free of reticular defects; exhibit a high electrical conductivity and high carbon:oxygen ratio, very small sizes, high aspect ratio and improved stability and purity; are safe, environmental friendly and inexpensive; and improve the gas barrier effect, liquid barrier effect, flame retardant properties, rolling resistance, thermal conductivity and electrical conductivity. DETAILED DESCRIPTION - Producing pristine graphene nanoplatelets having a carbon/oxygen ratio of greater than or equal to 100:1, comprises: (a) expanding flakes of intercalated graphite having a carbon/oxygen ratio of greater than or equal to 100:1 and a lateral size of less than or equal to 500 mu m by exposing the flakes to a temperature of 1300-12000 degrees C for less than 2 seconds, where the obtained expanded graphite has a carbon/oxygen ratio of greater than or equal to 100:1; (b) dispersing the obtained expanded graphite in water in the absence of a surfactant or in the presence of a surfactant in an amount of less than 1 wt.% the graphite; and (c) subjecting the obtained aqueous dispersion to exfoliation and size reduction treatment that is carried out by at least one of steps of (c1) treatment with ultrasounds at an energy level of 10-200 Wh/g of the graphite, or (c2) high pressure homogenization treatment carried out in a homogenizer, in which the graphite dispersion is pumped at a pressure above 35 MPa through at least one of micro-channels or necks having a section not greater than 500 mu m, where the particles of expanded graphite are caused to collide at an energy level of 5-200 Wh/g. The exfoliation treatment produces highly pure graphene having a carbon/oxygen ratio of greater than or equal to 100:1 in the form of nanoplatelets, at least 90% of which have a lateral size (x, y) of 50-50000 nm and a thickness (z) of 0.34-50 nm, where the lateral size is greater than the thickness. An INDEPENDENT CLAIM is also included for pristine graphene nanoplatelets, at least 90% of which have a lateral size (x, y) of 100 to less than 10000 nm, and a thickness (z) of 0.34-50 nm, and have carbon:oxygen ratio of greater than or equal to 100:1, where the lateral size is greater than the thickness.