Graphite Oxide Polymer Nanocomposites Preparation And Characterization

Nano-composite material is one of the hot topics in material science.It covers a wide range of subjects in science and has many theoretical and practical applications.The synergy between the organic with inorganic or the organic with organic improves the performance of the materials admirably compared to the corresponding macro-composite materials.Graphite oxide is low-cost,and it has many excellent physical and chemical properties which allow it being used as an excellent filler of nano-composite materials.In recent years,the polymer/graphite oxide nanocomposites were given more attentions.In this thesis,the graphite oxide was prepared by Hummers' method and the extent of oxidation was determined by the elemental analysis.At the same time,the structure and morphology of the products were characterized by SEM,XRD and FT-IR analysis. The FT-IR analysis reveals that a number of oxygen-containing functional groups,like carbonyl,hydroxyl,epoxy,and carboxyl,embedded in the carbon layers,and the presence of these functional groups makes graphite oxide strongly hydrophilic.The study of the oxidation process shows that the ratio of graphite and potassium permanganate ratio,the reaction time under low temperature process have influence on temperature on the structure and properties of products.The hyperthermal reaction in high temperature process decompound the oxygen-containing functional groups and impact the structure of products.Subsequently,the graphite oxide was exfoliated into thin-films by ultrasonication in the water or anhydrous ethanol and suspended steadily.The structure of the suspended graphite oxide nano-sheets was characterized by SEM,TEM and AFM analysis.The polyvinyl alcohol/graphite oxide nanocomposite was prepared by ultrasonic dispersion method.Composite superficial morphology was characterized by scanning electron microscopy,and microstructure was characterized FT-IR and X-ray diffraction. It can be found that graphite oxide nano-sheets dispersed in the polymer uniformly.This method can be used for a variety of water-soluble synthetic polymer.For hydrophobic polymers,a method to modify the graphite oxide nano-sheets by polyethylene lamellae crystals was used.The TEM figures show that a number of polyethylene lamellae crystals about 30-50nm intersperse among the graphite oxide nano-sheets surface uniformly.FT-IR and X-ray diffraction analysis results reveal that the presence of polyethylene lamellae can expand the inter-planar spacing of graphite oxide nano-sheets effectively.The integrity of graphite oxide nano-sheets structure is not disrupted and the properties of the GONPs are therefore retained in this way.Using toluene-2,4-diisocynate as the modifier to functionalize graphite oxide,and hydroxy-terminated polyethylene glycol was grafted to the surface of modified graphite oxide.The infrared spectroscopy and elemental analysis were used to characteriz the products,the process of TDI modification and polyethylene glycol grafted can be confirmed from characterization.