Research On Preparation And Properties Of Graphene/Epoxy Resin Composites

Epoxy resin was widely used in many fields as it had excellent bonding power and mechanical properties. But its poor thermal resistance and brittleness limited its use in the more demanding fields. Graphene are new two-dimensional carbon nano material with some peculiar physical and chemical properties. It is considered that graphene have great development potentiality and good development prospect. Due to the perfect mechanical properties, graphene have been widely used in polymer nanocomposites as reinforcements to improve their mechanical performance.In this paper, graphite oxide was prepared from the natural flake graphite through the intercalation oxide method. Few-layer graphene were prepared from graphite oxide by microwave heating exfoliation. And on the basis graphene/epoxy resin composites were prepared, and we studied influence of the content of graphene on mechanical properties and thermal stability of the graphene/epoxy resin composites.Graphene were prepared by microwave heating exfoliation. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) test show that oxygen-containing groups significantly increased the distance between the graphite layers. Scanning electron microscope (SEM) and atomic force microscope (AFM) show that graphene were transparent with approximate0.5-3nm in thickness and the layer within a10layers.In this paper, the graphene powder surface modified with silane coupling agent KH-560, and then graphene/epoxy resin composites were prepared. The structure and properties of the modified graphene and graphene/epoxy resin composites were characterized by FT-IR. Tensile properties and fracture toughness of graphene/epoxy resin composites was tested by electronic universal testing machine. Furthermore, the dispersion of the graphene in the matrix were characterized by SEM on fracture section of composite. Thermal stability of the composites was tested by TG-DTA. The results show that the addition of graphene can improve the material mechanical properties, and with the increase of graphene content, the tensile properties of the composite increases first and then decreases. The tensile strength, of the graphene /epoxy resin composites is76.6MPa when the content is0.5wt%, while the elastic modulus is2235.2MPa, the breaking elongation is4.05%and the fracture toughness is0.87MPa·m1/2. Compared with the pure epoxy resin, the tensile strength increases by about91%, the elastic modulus increases by about23%, the breaking elongation increased about127%and the fracture toughness increases by about56.5%. Modified graphene possesses perfect dispersity in epoxy resin and there exists compatibility to a certain extent between graphene and epoxy resin. Compared with the graphene/epoxy resin composites, the tensile strength increases by about6%, the elastic modulus increases by about2.9%, the breaking elongation did not change significantly and and the fracture toughness increases by about11.7%. TG-DTA tests showed that the heat stability of the graphene/epoxy resin composites is better than the pure epoxy resin.