Preparation And Properties Of The Er Of New Inorganic / Organic Hybrid Materials

Electrorheological fluids (ERF) are a kind of smart materials which are composed of high-dielectric-constant and low-conductivity solid particles dispersed in insulating liquid. While a sort of liquid was exposed in an external electric field,the material parameters of ERF such as viscosity,yield stress,and storage modulus can be changed obviously and reversibly. These characteristics find practical applications in many fields,such as actuators shock absorbers,active devices,human muscle simulators,ER tactile displays,photonic crystal and various other control systems.It is found that existing electrorheological(ER) material fails to meet application requirement in engineering,and now the composite ER material is come on. Composite particles are such particles as surface modification of solid particles and surface coating on solid particles,which makes property of the particles and surface performance show obvious difference. The composite particles can make some performance design to solid particles in order to prepare ER material with better performance,for example,density regulation of solid particles to improve the stability,surface hardness adjustment with flexible payload and so on. The discussion was carried on from the following respects based on the above assumptions in this text,and made certain achievement.1. Study on preparation and performance of PMMA/PBA/BaTiO₃ composite electrorheological fluidPMMA/PBA/BaTiO₃ composite material were synthesized by using sol-gel method and emulsion polymerization,NaHSO₃-K₂S₂O₈ as initiator,sodium dodecyl benzene sulfonate(SDBS) as emolsifier,and PMMA/PBA/BaTiO₃ composite ER material was prepared by direct vacuum distillation method. The composite material was characterized by IR and thermal analysis,and the mechanical properties of the composite ER fluids were tested by static sweep and dynamic sweep. The effects of electric field strength,concentration on rheological property were examined in static sweep. The results showed that ER effect of the fluid was better,and shear stress,apparent viscosity and dynamic yield stress enhanced with the increase of the electric fields intensity,meanwhile,shear stress and apparent viscosity also increase with the increase of the particle content.The impact of electric field strength,stress and frequency on viscoelasticity were investigated in dynamic tests and creep and creep recovery were also tested. The results showed that the composition system was provided with viscoelasticity,and elasticity gradually took the dominant position in system with the increase of electric field strength.2. Study on preparation and performance of PAN/TS-1 composite electrorheological fluidBy the initiation system of NaHSO₃-K₂S₂O₈,PAN/Titanium Silicalite molecular sieve(TS-1) composite material was prepared by in-situ polymerization. Fourier transform infrared spectroscopy(FT-IR) , scanning electron microscopy(SEM) ,transmission electron microscopy(TEM),differential scanning calorimeter(DSC) and N₂ absorption were adopted to study the morphology and chemical composition of these composites. The composite particles were prepared as ER fluids with silicone oil,the mechanical properties of the composite ER fluids were tested by static sweep and dynamic sweep. The experimental results were shown as follows.(1) AN can be polymerized in the hole of the molecular sieve with NaHSO₃- K2S2O8 as initiator because of the absorption of the molecular sieve,which made molecular chain consist inside and outside hole and connect PAN molecular to form TS-1/PAN composite material.(2) The ER effect of the composite fluid was better. The change of shear stress and shear-thinning behavior were distinct. Modulus and elastic response enhanced with the increase of the electric fields intensity,which indicated that chain structure field-aligned became further firmer.(3) In addition,the stability of PAN/(TS-1) composite ERF was improved.3. Study on preparation and performance of PAM/MCM composite electrorheological fluidThe outside electronic-shell structures of rare earth elements are similar. They have 4f orbits electronic-shell structures and can spin polarization. Accordingly, they are widely used because of their special properties such as light, magnetic, electric and catalysis.By the initiation system of AIBN,PAM/MCM composite material and modifica- tion of carboxylic acid rare earth was prepared by in-situ polymerization,and composite ER material was prepared by direct vacuum distillation method. The composite particles were characterized using different techniques such as FT-IR,SEM TEM,X-ray diffraction (XRD),DSC and N₂ absorption. The mechanical properties of the composite ER fluids were tested by static sweep and dynamic sweep. The effect of strain,frequency and electric field strength on ER effect were discussed by static sweep,dynamic sweep and creep and creep recovery.The results showed that the composite materials of PAM/MCM/RE were prepared by in-situ polymerization. The composite ERF belongs to pseudoplastic fluid. With the enhancement of the electric field intensity,shear stress and modulus increased,meanwhile elastic response enhanced,which further indicated the formation of chain structure. In addition,the stability of PAN/(TS-1) composite ERF was improved,compared to the above two ER fluids.