Montmorillonite Based Nanocomposites Er Fluid Materials Preparation And Its Properties

According to the physics and chemistry design, we prepared electrorheological (ER) materials of montmorillonite/titania nanocomposite, montmorillonite/starch as well as montmorillonite/formide/starch composite using modified sol-gel technique and the way of blending solution, respectively. Thermo-gravimetry analysis (TGA), x-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersion spectrum (EDS) and fourier transform infrared spectroscopy (FT-IR) were adopted to study the morphology and chemical composition of these composites. The nanocomposite particles were prepared as ER fluids with silicone oil. The ER properties and dielectric properties of ER fluids containing the composites had been investigated in detail. The experimental results were shown as follows: 1. A new kind of montmorillonite/titania (MMT/TiO2) nanocomposites was prepared by a modified sol-gel technique. XRD measurements showed that TiO2 in the composites was anatase nano-crystallite with 5-10 nm size. SEM images showed that some of the TiO2 nano-crystallites coated on the surface of the MMT and some of them plugged into the gap between flakes of MMT. Combining XRD result with SEM images, it was clearly that the MMT and TiO2 nanocrystallites formed a netlike nanocomposite structure. The yield stress, operational temperature range and anti-sedimentation ability of the ER fluids using such composite particles as dispersed phase had been greatly improved compared with single pure MMT and TiO2 ER fluids. The maximum yield stress of typical MMT/TiO2 composite ER fluid (25vol% in silicone oil) was 16 kPa at 4kV/mm DC electric field, which was about 5.3 times that of pure MMT and 26.7 times that of pure TiO2 ER fluids at the same conditions. The dielectric measurements showed that the regular change of dielectric properties of MMT/TiO2 suspension with TiO2 content was in accordance with the change ofyield stress of MMT/TiO2 suspension with TiO2 content.2. New types of MMT/carboxymetnyl starch (CMS), MMT/Cation starch ER materials were also synthesized by solution reaction. ER measurements showed that the ER properties of composites depended on the content of starch. When the weight ration of MMT and starch was closed to 1:0.1, the yield stress of ER fluid could reach its maxium. The yield stress of the typical ER fluid was over 6.5 kPa at 4 kV/mm electric field, which was 2.2 times that of pure MMT ER fluid and five times that of CMS ER fluid, respectively. When the weight ration between MMT and starch was closed to 1:1 and 1:0.4, the yield stress of ER fluid was lower than that of pure MMT ER fluid though this value was higher than that of pure CMS ER fluid. When the weight ration between MMT and starch was closed to 1:1 and 1:0.4, the yield stress of MMT/Cation starch ER fluid was even lower than that of pure MMT and cation starch ER fluids.3. The composite particles of ternary system of MMT/Formide/CMS were prepared by solution reaction. ER measurements showed that the ER properties, compared with MMT/CMS composite, could been further enhanced by formation ternary system composites. Interestingly, it was found that the ER properties of this ternary composite depended on the content of formide. When the weight ration between MMT and formide was closed to 1:0.08, the yield stress of ER fluid could reach its maxium and the typical yield stress was over 8.3 kPa at only 2 kV/mm electric field, which was 3.2 times than that of MMT/CMS ER fluid. When the electric field was 3 kV/mm, the yield stress was over 12.0 kPa, which was 2.4 times than that of MMT/CMS ER fluid.