| Electrorheological (ER) fluids are materials that undergo fast, reversible and obvious changes in their rheological properties upon the application of electric field. This rapid response and reversible change make it possible to apply the fluid in switch, brakes, clutch, valve and other intelligence-control areas. Although a wide variety of ER fluids applications have been identified, and a number of ER fluids are already produced on a commercial scale, they have not yet enjoyed widespread commercialization mainly because of the low yield stress (a few kPa) achieved up to now so finding and preparation some high efficient electrorheological materials is the most important subject.In this thesis, BaTiO(C2O4)2 nanocoparticles is prepared by the oxalate precipitation method, on this base the BaTiO(C2O4)2/PAn nanocomposite is prepared by in-situ complex technology, The electrorheological (ER) fluid based on BaTiO(C2O4)2 and BaTiO(C2O4)2/PAn nanocoparticles is fabricated using methyl silicon oil as dispersing medium. The influences of the mass of particles, the reacting ratio, E and temperature on the properties of ER fluids have been studied.We use traditional oxalate precipitation method to prepare BaTiO(C2O4)2, different sizes of particles were prepared by control the reaction time and then fully characterised by TEM, FT-IR, XRD, TG-DSC and so on. The result indicated that the size of particles is increase with the reaction time, but with the same Ba and Ti radio. The electrorheological (ER) fluid based on BaTiO(C2O4)2 nanocoparticles is fabricated using methyl silicon oil as dispersing medium. The result shows that the ER fluid with 70nm about particles shows the best electrorheological effect. The mass of particles play a important role on the electrorheological effect, when the mass is 70%, the ER fluid shows the best electrorheological effect, the rate stress up to 42kPa when the E is 5kV/mm. Furthermore the ER fluid has good temperature stability, after treated by electric field, the repetition is improved but the electrorheological effect is worse.BaTiO(C2C>4)2/PAn nanocoparticles is prepared by in-situ comples thchnology and fully characterised by TE1VL FT-IRn TG-DSC and so on. The rheology of the ER fluids is measured, The research indicated that the particles have a great dismatching between the particles and methyl silicon oil, so the ER fluid show better electrorheological effect. The reacting radio of PAn (w) has a important effect on the electoroheological effect, when w is 0.42, the ER fluid show giant electrorheological effect, the rate stress up to 96kPa when the E is 4kV/mm. The later ER fluid has higher stress and bigger curent density. Temperature has great effect on the e' ande" .When w is 0.42 the response time is less than 300ms. |
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