Graphene Has Excellent Mechanical Properties
Graphene is a two-dimensional honeycomb carbon material, composed of carbon atoms in accordance with the hexagonal arrangement. Carbon and carbon atoms by the combination of sp2 hybrid, its structure is very stable. The special structure of graphene leads to its many excellent properties. Graphene is currently found in the hardness of the largest material, and has excellent mechanical properties, the theoretical surface area of up to 2600m2 / g, with outstanding thermal conductivity, up to 3000W / (m · K). In addition, graphene also has good conductivity. At room temperature, its electron mobility can be as high as 20000cm2 / (V · s).
Due to the excellent properties of graphene, the researchers consider adding it as a reinforcement to the matrix material to improve the performance of the matrix material. However, the specific surface area of graphene is often brought together, not only reduces its adsorption capacity but also affects the excellent performance of graphene itself, thus affecting the performance of graphene reinforced composite materials. Moreover, this reunion is irreversible, unless the application of external forces, such as ultrasound and strong mixing, so that evenly dispersed. In order to obtain excellent graphene reinforced composites, researchers have done some research in overcoming graphene agglomeration.
One of the commonly used methods is to oxidize graphite and ultrasound to produce off-oxide graphite, and then by chemical method to reduce the graphene, the preparation of graphene between the existence of a strong van der Waals force, easy to gather in the solution. Another common method is to uniformly disperse the graphene in an organic solvent or an aqueous solution of a surfactant to adsorb the molecular or surfactant molecules on the surface of the graphene, and to achieve the effect of the monolithic graphene dispersion. The ability to inhibit the agglomeration of graphene by physical or chemical modification has been demonstrated, but whether the impurity introduced during the formation of the composite affects the properties of the composite remains to be studied.
Some surface modifications and other methods can also be used to improve the dispersibility of graphene. In order to improve the surface bonding of graphene and copper matrix, it is possible to obtain the composite material in which the graphene is uniformly dispersed in copper. It is found that the graphene can be uniformly dispersed in the copper matrix by the observation of the composite material. Jing used gallic acid with strong reducing ability as stabilizer and reducing agent to obtain highly dispersible graphene. Their analysis is due to the formation of π-π conjugate interactions between the benzene ring structure and the graphene in the molecule, which is adsorbed on the surface of the graphene as a stabilizer. This makes the graphene sheet has a strong negative charge, to prevent the further accumulation of graphene together to make it more difficult to reunite, to ensure that the prepared graphene has a high dispersion performance.