| Epoxy resin has some merits such as high adhesion, good chemical stability and low shrinkage rate, etc, so it has been widely used in coatings, adhesives and other domains. Majorities of the epoxy resin are mostly viscous liquid or solid, which can be dissolved in organic solvents but not in water. The organic solvents will do harm to environment and human health, so developing waterborne epoxy resin becomes a problem that calls for immediate solution. What’s more, some drawbacks of waterborne epoxy resin limit its application in harsh environments, such as brittleness, poor water resistance, poor heat and wear resistance.The emergence of nanotechnology has offered the opportunity and motivation for improving the performance of waterborne epoxy resin. The flexibility, heat and wear resistance, water resistance of waterborne epoxy resin are expected to be fully improve when it modified by nanoparticle. In this paper, a steady waterborne epoxy resin emulsion was prepared firstly through chemical modification method. And then, combined it with silica sol whose surface was modified with silane coupling agents, in order to obtain a kind of high performance waterborne epoxy resin nanocomposites.The main contents and related achievements are as follows:1.A epoxy resin emulsion with good stability was prepared via reaction of bisphenol A epoxy resin E-44with glycine to introduce hydrophilic group into epoxy resin. In order to find out the optimum reaction conditions, the influences of reactive conditions such as the pH value of glycine aqueous solution, the amount of solvent, reaction time and temperature, the mole ratio of glycine to epoxy resin, and neutralization degree were investigated. The structure of the product was characterized by Fourier transform infrared spectroscopy (FT-IR), and the results show that the hydrophilic groups has successfully introduce in the epoxy resin. The particle size and morphology of the emulsion was observed by laser particle size analyzer and optical microscopy, found that the epoxy aqueous dispersion with good stability and the minimal particle size about670nm would be obtained under the optimum reaction conditions.2.The surface of nano-SiO2was treated by3-glycidoxypropyl-trimethoxysilane (KH-560). FT-IR and TGA results showed that the KH-560was grafted onto the surface of nano-SiO2successfully, and grafting rate was5.01%. Sedimentation experiments showed that lipophilicity of the modified nano-SiO2was improved apparently, which provides guarantee for the nano-SiO2uniformly dispersed in the epoxy resin3.The nano-SiO2modified by KH-560was added into waterborne epoxy resin to prepare KH-560/SiO2-epoxy resin composite emulsion. The effects of the amount of nano-SiO2on the property of the composite emulsion and composite film were discussed. And the result showed that the size of emulsion become bigger and the stability of emulsion becomes worse, while the performances of the composite film presented the trend of first getting better then worse with the increase of the nano-SiO2content. When the content of nano-silica was9.00%, the composite emulsion has good storage stability, the nanoparticles dispersed homogeneously in epoxy matrix and the properties of composite film reached a maximum value such as heat and wear resistance, mechanical properties. For illustrate the advantages of KH-560on the nano-SiO2, also prepared pure SiO2-epoxy composite, compare these two composites, found that the properties of the KH-560/SiO2-epoxy composite were better than that of the pure SiO2-epoxy composite. |
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