Synthesis of graphene nanoflakes by grinding natural graphite together with NaCl in a planetary ball mill

Abstract

Natural graphite is a soft material that conventional milling methods fail to grind into nanoparticles. We found that adding NaCl into graphite during milling allows obtaining graphene nanoflakes of about 50[Formula: see text][Formula: see text][Formula: see text]200[Formula: see text]nm2 as evidenced by Transmission Electron Microscope (TEM). NaCl particles are substantially brittle and harder than graphite, serving as milling agents by both helping to chop graphite into smaller pieces and preventing graphite particles from agglomeration. After milling, NaCl can be easily washed away by water. Probable mechanism for exfoliation of graphene during the modified ball milling may be explained by NaCl and graphene slipping or sliding against and over each other, exfoliating the graphene particles into thin layers.

Recent Developments Concerning the Dispersion Methods and Mechanisms of Graphene

“…The prepared graphene can be well-dispersed in organic solvents, water, or culture media. Alinejad et al [48] obtained graphene nanoflakes of about 50 × 200 nm 2 by adding NaCl during ball-milling. Because graphene particles are soft, the brittle and hard NaCl particles can serve as milling agents to grind the graphene into thin layers and keep graphene particles away from agglomeration.…”

Preparation of Graphene Nanoplatelets by Thermal Shock Combined with Ball Milling Methods for Fabricating Flame-Retardant Polymers

“…Beside the factor of compatibility between Gnps and polymers, the size and layer number of Gnps also play an important role. Gnps can be prepared by two main methods, the bottom-up and top-down methods [10,11]. e bottom-up methods, such as chemical vapor deposition and epitaxial growth, are expensive and cannot meet the requirement of big quantitative production of Gnps.…”

Mechanochemical Routes to Functionalized Graphene Nanofillers Tuned for Lightweight Carbon/Hydrocarbon Composites

“…[101] Alternatively, hydrogen addition is used in mechanochemical reduction of graphene oxide. [102] Meanwhile an extraordinarily wide range of MFG bearing hydroxyl, carboxylic acid, halogen, five-,and six-membered N-heterocycles, sulfonic acid, and even phosphate groups have been prepared via graphite mechanochemistry in the presence of gases like CO 2 , [96,99] N 2 , [103,104] NH 3 , [105] H 2 , [106] O 2 , [100] Cl 2 , [107] F 2 , [107] and SO 2 , [99] liquids like Br 2 , [106,107] H 2 O, [108] SO 3 , [99,109] CO 2 /SO 3 , [99] as well as solids like red phosphorous, [110,111] sulfur, [112][113][114][115] melamine, [116][117][118][119] urea, [104,120,121] KOH, [122] NaCl, [123] Mg, [101] Fe, [124] Si, [125][126][127] polystyrene, [128] cellulose, [64] chitin, [129] polyvinylpyrrolidone, [130] polyetherketone, [131] and I 2 . [106,…”