| Electrorheological(ER) fluids are suspensions in which nano-or micron-sized solid particles are dispersed in the insulating liquid suspension. Because of their controllable rheological behavior, ER fluids have a great prospect in numerous electromechanical decives. The yield strength of the ER fluid has been able to meet the requirements of engineering applications, but due to the complex preparation, the high cost of raw materials, it is difficult to achieve industrial production; at the same time, in the course of the sedimentation and the influence of impurities, also limits the ER fluids the actual application.In order to solve the above problems, in this paper, an anhydrous reaction system was provided, we choose polyhydric alcohols and tetrabutyl titanate as raw material, and a small amount of ethanol as the dispersed phase, by means of direct precipitation method, high current effect and stable performance of ER particles were prepared.This thesis work consisted of the following three aspects:By selecting different polyhydric alcohols to react with tetrabutyl titanate, different polyhydric alcohol-modified titanium particles were obtained. The results show that only1,3-propanediol and glycerol react with tetrabutyl titanate quickly and obtained white precipitates. Depending on the reaction phenomenon and characterization results, we believe that under the present experimental conditions, the substance of the precipitation reaction is the reaction between the primary alcoholic hydroxyl group and tetrabutyl titanate, however, the secondary alcoholic hydroxyl group finally completely remains in the interior of the particles instead of participating in the reaction. By comparing the electrorheological performance of these two particles, glycerin-modified particles were significantly higher than that of1,3-propylene glycol-modified particles, the reason is that a large number of hydroxyl groups group contains in the glycerol-modified particles.By adjusting the molar ratio of glycerol and tetrabutyl titanate, different glycerol-modified particles(Gly-O-Ti) were prepared. The results indicated that the ER fluid prepared with the particles in a mol ratio (nGly/nTBOT) of2.5presented the best ER performance. Therefore, ER fluid with70wt%particles in the optimal mol ratio was prepared. Its yield strength reached220kPa at5kV/mm, meanwhile the leakage current is small. By comparing the particle size of different amount of glycerol modified particle size and its ER effect,it can be easily found that the particle size has an important influence on the performance of the ER fluid:the larger the particle size, the weaker ER effect wo got.The graphene oxide (GO) doped Gly-O-Ti composite particles (GO-Gly-O-Ti) are prepared by doping a certain amount of GO into the Gly-O-Ti particles, there are a large number of reactive groups on the surface of GO (such as carboxyl), the GO can be easily bonded to the Gly-O-Ti particles; the addition of GO can significantly improve the anti-sedimentation properties of the ER fluids, because of GO has a relatively large comparative area,it can open a parachute in silicone oil the structure, thereby improving the anti-sedimentation properties; With the increase of GO stronger electrorheological performance can be observed, but the leakage current has increased dramatically. This is mainly because there are a large number of polar groups in the surface of the GO. So the doping amount of GO may have an optimum value in the experimental conditions, in the present paper, we believe that when the doping amount of GO reaches25mg can be the optimum. |
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