The Study Of Preparation And Application Of Graphene Oxide And Its Nanocomposites

Graphene oxide is the derivative of graphene, whose basal plane and edges are decorated with functional groups, such as carboxylic, phenol hydroxyl and epoxide groups. It has a huge specific surface area, ultra-high strength, superior mechanical properties and excellent flexibility, which can easily form nanosheets in aqueous phase and it is easy to form intercalation complexes with the polymer, ceramic, cement etc. Simultaneously it can reinforce complexes. With preliminary study of our research group, mixing GO into cement based materials can regulate the microsturcture of cement hydration crystals and improve the growth of hydration crystals, on the basis of our previous studies, the graphene oxide was prepared by Hummers method and its nano-lamellae disperse liquid was obtained by ultrasonic.The SGO was obtained by using sulfonating agent H2SO4, ultimately, prepared GO modified superplasticizer/cement based composites, SGO/cement based composites and GO/polyacrylate resin retannage, then used them in cement-based materials and leather tanning agent, the main works are as follows:(1) Graphene oxide was prepared by Hummers method and its nano-lamellae disperse liquid was obtained by ultrasonic. Characterized GO with Fourier transform infrared spectrometer(FTIR) and so on. The result showed that the prepared GO had good dispersibility and stability, the oxygen content reached to 50.94%, and the thickness of GO was 0.65nm.(2) Use GO with different concentration modify superplasticizer, then added the complex into cement paste, studied its effects on cement hydration time, cement hydration product shape, cement paste fluidity, cement pore volume and mechanical properties of mortar, result indicated that GO modified superplasticizer can promote the formation of cement hydration reaction, so that it can dense cement based materials, simultaneously, it can make the tensile strength of cement based composites a slightly higher, and the compressive strength improved significantly.(3) Summarize the mechanism of GO regulating the growth and shape of cement hydration crystals, the result showed that different concentration of GO modified PC can regulate the microstructure of cement based materials, and with the increase of concentration, the structure of cement hydration crystals kept much denser. This study has great significance in improving the compressive strength and crack resistance of cement-based materials.(4) The SGO was obtained by using sulfonating agent H2SO4, then mix the SGO and superplasticizer into cement at different content. Investigate its effects on cement hydration time, cement hydration product shape, cement paste fluidity, and cement pore volume and mechanical properties of mortar. The result showed that the SGO can dense cement structure so that to reinforce the cement-based materials.(5) Using ammonium persulfate as the initiator, acrylic acid, methacrylic acid, acrylamide, acrylonitrile and graphene oxide as monomers to synthesis graphene oxide and polyacrylic acid resin retannage by situ polymerization. Take retannage experiment, discussed the influence of the heat re-tanning agent, tensile strength, tear strength, thickening and breathable stability for leather. The result showed that, in comparation, the leather retanned with Graphene oxide modifided Polyacrylic acid resin retannage is good in grain smoothness, fullness and elasticity, leather shrinkage temperature slightly is higher and leather "lost color" phenomenon has improved a lot. Tensile strength and tear strength have greatly improved.The innovation of this paper lied in using graphene oxide modified carboxylate superplasticizer, then the modified carboxylate superplasticizer mixed with cement based composite materials, the template and induction effect of graphenen oxide controlled the microstructure of cement hydration crystal, so as to reinforced cement based composite materials. And for the first time, introduced the graphene oxide in preparation of leather retanning agent, improved the shortcomings of polyacrylic and resin retanning agent, such as the "lost color" phenomenon.