Prepration Of High-concentration Graphene And Its Furfuryl Alcohol-modified Study

Graphene is found to be a kind of carbon nano-material with two dimensional plane structure. Its special monoatomic layer enables it to hold a lot of unusual physical and chemical property. Application and study towards graphene has been a hot top in recent scientific area. The basic structure of graphene was six-membered ring with benzene structure, which is found to be the thinest two-dimensional material so far. Currently the preparation methods of graphene includes stripping mechanically, chemical vapor deposition method, epitaxial graphene on SiC substrate, oxidation and reduction method, organic synthesis method and direct stripping in liquid. Graphene is widely used in ultracapacitor, sensor, solar battery, electronic devices, catalysts and drug carrier. For its special physical and chemical property, it is meaningful to prepare high-qualified graphene economically in large scale.As we know, graphene was not easily to be dispersed and few kinds of solvent could be utilized in the course as result of no functional groups on the surface. Minor variation in polarity of solvent or temperature could cause cluster of graphene, which is also obstructive in the preparation of graphene functional material. Thus covolently modification could improve the dispersability of graphene and make it easily be bonded with active functional groups. Besides, bandgap of graphene could be opened to change the physical and chemical property, which expand its application in chemical devices. So it is necessary to make graphene covolently functionized.Proceeding from microcrystal graphite. The experiment began with heat pretreatment through solvent in high temperature and pressure. Then graphite layers was stripped through ultrasonic treatment in liquid to obtain graphene dispersion of high concentration and quality. Functionliazation of graphene was carried out Diels-Alder reaction was carried out to functionilize graphene in order to achieve good dispersibility. Water-soluable graphene dispersion was prepared to broaden the research and application in biologic and medical areas.The work in the thesis can be listed in several point,as the following shows:(1) Microcrystalline graphite as raw materials, N-methylpyrrolidone (NMP) solvent, high pressure heat treatment of graphite, the graphite layer spacing increases crystallites, and in different organic solvents sonicated for2hours to prepare a series of high-density, high dispersion of graphene, the maximum concentration of 0.75mg·mL-1. We use Raman spectroscopy (Raman), transmission electron microscopy (TEM) and atomic force microscopy (AFM) of the prepared graphene structure and morphology of the system characterization and analysis, we found that we prepared graphene sheet is large, quality preferably mainly composed of a single layer or a few layers.(2) We used a novel covalent functionalization method-click chemistry on the modified graphene. production of graphene sheets via exfoliation of graphite in extreme condition,and subsequent functionalized with furfuryl alcohol,which offers a feasible route for Diels-Alder cycloaddition reaction in the liquid phase. FTIR and Raman are used to confirm the covalent functionalization process.Thermal gravimetric analysis(TG) showed grafting ratio of furfuyl alcohol was14%.The dispersabilty of funcitionized graphene was highly improve and it could scatter steadily in water for3months. The advantage of this preparation method was furfuryl alcohol could be economically obtained and wild reaction in the preparation process.