Preparation And Properties Of Poly-arylamine/montmorillonite Nanocomposite Electrorheological Field

Electrorheological (ER) fluid is a kind of smart material. ER fluids typically consist of electrically polarizable particles dispersing in low-dielectric oils. Application of an electric field can induce polarization of the suspended particles. As a result, a characteristic fibrillation structure along the electric field direction can be formed in a very short time scale (a few millisecond), and the apparent viscosity and shear stress can increase several orders of magnitude. Because of their controllable viscosity and short response time, ER fluids have been regarded as one kind of smart material for active devices. In addition, the characteristics of ER fluids such as short response time, low power consumption, smoothness of operation and mechanical simplicity, ER fluids have been considered for various applications in mechanical engineering for electromechanical couplingdevices such as an engine mount, shock absorber, clutch, ER valve, robotics arm and several control systemDuring the past decades, studies on ER fluid materials were focused on those of inorganic oxides and organic polymers. In 1985, Block was firstly reported the synthesis of condensed aromatics ER fluid, and it was the indication that the beginning of anhydrous ER fluid. Unfortunately, some available ER materials, some with relatively low shear stress and narrow operating temperature, some with poor suspension stability, are not satisfactory in engineering. Therefore, the development of high performance ER fluids via optimizing and tuning conducting polymers has been a main subject of considerable interest for the application.Montmorillonite (MMT) clay is an important class of lamellar inorganic compounds, contains negatively charged layered silicates, which are bonded with metal cations such as Na+ or Ca2+ by ionic bonding. Whose interlayer spacing can be modified by cation exchange. When the MMT is exchanged with cations, its inner layer spacing becomes large enough to be penetrated by a monomer. Therefore, MMT has been widely used for preparing the organic-inorganic nanocomposite.In this paper, according to the physics and chemistry design, we prepared polyaniline-montmorillonite nanocomposite as well as its derivatives using emulsion intercalation polymerization, and the structure of these nanocomposite particles were characterized by IR, XRD and TEM spectra, respectively. The dielectric propertiesof nanocomposite particles had been tested, and then their ER properties had been strided. The experimental result are given as follows:1. Polyaniline-montmorillonite clay nanocomposite (PANI-MMT) with large dielectric constant and suitable conductivity was synthesized by emulsion polymerization. TEM shows that the diameter of PANI-MMT particles is about 100 nm. The dielectric constant of PANI-MMT nanocomposite was increased 5.5 times that of PANI and 2.7 times that of MMT, besides, the conductivity of PANI-MMT particle was increased about 10 times that of PANI at 1000 Hz and 20. Meanwhile, the dielectric loss tangent can also be increased about 1.7 times that of PANI. The ER properties of the PANI-MMT/silicone oil suspension were then investigated. The electrorheological properties of the suspensions of PANI-MMT particles in silicone oil (30wt%) have been investigated under DC electric fields. In 3 kV/mm field, the yield stress is 7.19 kPa (20, r=5 S-1), and leaking current density is less than 30A/cm2. Meanwhile, it was found that this anhydrous PANI-MMT ER fluids not only displays a notable ER properties under DC electric field, wider temperature range but also possess an excellent anti-sedimentation stability. In the range of 10-100, the yield stress changed only 6.5 % with the variation of temperature. The sedimentation ratio of PANI-MMT ERF was about 98% after 60 days.2. Poly-Af-methaniline/montmorillonite nanocomposite (PNMA-MMT) particles were synthesized by an emulsion intercalation method and characterized by IR, XRD and TEM spectrometry, respectively. TEM shows that the diameter of PNMA-MMT p...