Study On The Preparation And Properties Of Polystyrene(ps)/graphene Nanocomposites

Graphene has attracted the attention of the entire world due to its excellent electrical, thermal and mechanical properties. Therefore, the polymer/graphene nanocomposites materials were prepared and applied in many fields. Composite materials can be divided into two parts, one is structural composites and the other is functional composites. Electrospinning and electrostatic force driven self-assembly technique are two simple and highly efficient methods to prepare composite materials. The porous and fibrous nanocomposite membranes by electrospinning were prepared and applied in adsorption and filtration fields due to its high specific surface area in our study. Furthermore, the hollow graphene spheres by electrostatic force driven self-assembly were fabricated as we expected, which presented excellent capacitive performance as an electrode materials.In this thesis, graphene nanocomposite fibrous membranes were prepared by electrospinning technique and hollow graphene spheres were obtained by electrostatic force driven self-assembly. We systematically investigated the parameters which effected the structure of the nanofibers and hollow graphene spheres. We also investigated the electrochemical capacitance performance of the hollow graphene spheres. The results as followed1. Preparation of Polystyrene(PS)/graphene nanocomposite fibers. We obtained the N,N-dimethylformamide(DMF)/graphene solution by substituting the water in the graphene dispersion. Then, PS was added into the DMF/graphene solution to prepare spinning solution. We got the graphene-embedded PS/graphene nanocomposite fibers through electrospinning. We found that the specific surface area of the nanocomposite fibers increased with the concentration of the graphene increased under a fixed applied voltage, feeding rate and collecting distance.2. Study on the oil adsorption performance of the PS/graphene composite fibrous membranes. Oil slick was formed when oil was added onto the surface of the water. The PS/graphene composite fibrous membranes were soaked in the oil slick. After certain soaking time, the quality change of the fibrous membranes during soaking were measured to characterize the oil adsorption performance of prepared fibrous membranes. The oil absorption ability increased with the quantity of graphene increased.3. Preparation of hollow graphene spheres. PS, methyl acrylyl ethyl trimethyl ammonium chloride(DMC), azodiisobutyronitrile(AIBN), methanol and deionized water were added to a four-necked flask equipped with an anchor-like paddle stirrer and a reflux condenser. We got the positively charged PS spheres after dispersion polymerization. When added the negatively charged graphene oxide, electrostatic force driven self-assembly was happened. The paste then was heated at 500 ℃ to get the porous hollow graphene spheres. It indicated that hollow graphene spheres with different diameters and pore sizes have been obtained by simply adjusting the diameter of PS spheres.4. Study on the electrochemical capacitance performance of the hollow graphene spheres membranes. The PS/GO composite materials were filtrated to get the ultrathin composite membranes. Then the composite membranes were heated to remove the PS spheres and to restore GO. Then we obtained the hollow graphene spheres membranes electrode. The electrochemical capacitance performance of the hollow graphene spheres membranes electrode were investigated. Compared with the existing electrode materials, the hollow graphene spheres membranes electrode displayed excellent electrochemical capacitance performance.