Preparation Of Graphene By Oxidation-Reduction Method And Study Of Its Composite Properties

Graphene is a two-dimensional material which is only one-atom layer thick. As a new carbon material, graphene possesses excellent physical, chemical and mechanical properties. In this thesis, graphene was prepared by oxidation-reduction method, the influence of the dosage of potassium permanganate, reaction time and reaction temperature on the degree of the graphite oxide during the oxidation phase were investigated by UV-visible absorption spectrum(UV-vis), fourier transform infrared spectroscopy(FT-IR), comprehensive thermal analysis(TG-DSC), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). Graphite oxide was reduced to form r GO by thermal reduction, and the effect of heating rate and temperature on the r GO was discussed. Meanwhile, the polymer composite was prepared by filling the r GO into nylon 1010 and its mechanical and friction properties were studied.The main contents and results can be summarized as follows:(1) Graphite oxide was prepared from flake graphite by Hummers method. The degree of oxidation of the samples improved with the increasing of the amount of the oxidant, the experiments results indicated the products had the highest oxidation level when the mass ratio of KMn O4 and graphite was 3: 1. The graphite oxide would also improve by extending the reaction time of 35℃-stage, the result showed the long reaction time could promote the oxidation of flake graphite. In addition, the distance between layers of graphite oxide became larger due to the high reaction temperature which was beneficial to the preparation of few layer during the reduction process.(2) Graphene was prepared by thermal reduction method, heating rate and reaction temperature were discussed. the graphite oxide layer could be exfoliated only when there was high heating rate. At the same time, the reduced graphene oxide sheets would be thinner with the higher temperature.(3) Thermal analysis showed that the composite had a higher crystallization temperature by filling r GO or graphite into Nylon1010. The results of tensile strength, impact toughness and friction experiments showed that the composite material had the best performance when the filling ratio was 0.4 wt%. If the ratio was larger, the composite properties declined significantly because the agglomeration would occur owing to stress concentration.