The article describes the process of liquid-phase shear exfoliation of graphite in a rotary apparatus with moving blades, in water and I-20A oil (Rosneft, Russia) used as a liquid. The linear dependence of the process intensity on the shear rate and graphite concentration in the initial suspension are established in the paper. To increase the share of graphene converted into graphene plates, it has been proposed to reduce periodically the concentration of graphene plates in suspension by adding pure liquid. It was found that the exfoliation rate of graphite is directly proportional to the concentration of graphite in the initial suspension and the rotor speed. The resulting graphene-containing oil-based suspension was used to modify greases.
The motion of a graph-containing viscous fluid between stationary and rotating disks is considered. The initial differential equations of motion for the elementary volume of a liquid are compiled and the initial conditions are determined. Assuming that the flow in the gap is a Couette flow, an analytical solution has been obtained to change the radial and angular coordinates of the elementary volume with time. With the use of the mathematical package Maple, characteristic trajectories of the movement of elementary volumes of fluid in the gap between a fixed and rotating disk with different consumption characteristics and geometry are obtained. Calculated speed, time of stay and the path traveled by an elementary volume, depending on the initial coordinate of the thickness of the gap.
Lubricants modified with nanosized particles are of great interest to science and industry, since they have much better tribological characteristics compared to traditional lubricants. One of the most promising nanoparticles is graphene, which has an extremely low coefficient of friction, is very wear-resistant and environmentally friendly. Today, the main problem for the development of a new nano-lubricant is the creation of an environmentally friendly and cheap technology for the industrial production of graphene suspensions or graphene concentrates for the modification of traditional lubricants. The article describes the process of liquid-phase shear exfoliation of graphite in a rotary apparatus with moving blades, in synthetic oils. The kinetic dependences of the exfoliation process, i.e. the dependence of the concentration of graphene nanostructures in suspension over time at different values of the process parameters. It has been experimentally proved that using a stator-rotor mixer with moving blades, it is possible to obtain graphene nanostructure concentrations of at least 2 mg / ml.
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