The Synthesis And Electrorheological Properties Of Poly (P-pheylene Vinylene)

Electrorheological fluid(ERF) is a new type of intelligent material, which undergo fast,reversible and obvious changes in their rheological properties upon the application of electric field. Such kind of materials has a broad prospect in electrical- mechanical conversion, shown a good momentum of development. In this paper, the nature of the ERF and its theoretical model as well as its composition and application has been extensively reviewed. Ladder-liker polymer poly(p-pheylene vinylene) was synthesized and identified. The electrorheological(ER) effect of PPV-base suspensions were also studied.α,α′-Dichloro-p-xylene was synthesized based on the chloromethylation reaction of benzyl chloride. Poly (p-pheylene vinylene) was synthesized via Gilch method and solid phase synthesis. The reaction conditions were thoroughly investigated. The conjugated polymer was characterized with IR, elemental analysis etc. The surface morphology of the polymer was measured with a scanning electron microscope. Thermal stability of the polymer was measured with thermal analyzer. Dielectric property of the particles was measured. Density of the polymer was measured with density bottle method. Results show the synthesized polymer was in well agreement with the design requirement of electrorheological materials.The ER properties of PPV-base suspensions were intensively investigated by the rheological testing equipment. The results show that, the PPV-SO suspension without doping was found to display the negative ER effect in a cetain area, showing the existence of critical electric field strength. PPV synthesized by different methods has shown very different ER effect, for the difference between the degree of conjugated. PPV synthesized via Gilch method display lesser negative ER effect.The addition of doping can improve the conductivity and dielectric constant properties of particles. After doping, the PPV-SO suspension shows the positive ER effect. The rheological behavior meet the Bingham equation under the electric field, and the viscosity of the system increased dramatically. Doping time and ways influence conductivity and dielectric constant properties of PPV, leading to differences of ER effect.The effect of dispersed particle concertration, size of particles, activator and temperature upon PPV-base suspensions was also discussed. The results show that the shear stress of PPV-SO suspension is augmenting as the particle concertrations; Moderate size of dispersing particles appears the good stability and good ER effect. Both water and glycerol are the activator of PPV-SO suspension, which can buildup system's ER effect. Adding a surface-active nature of glycerol will be much better. Employed g temperature affect ER effect of PPV-SO suspension, The yield stress has a maximum as increasing the employed temperatureThe stability of PPV-base suspensions was also investigated. The results show that the stability of the ER system depends on the density difference of dispersed particles and dispersing medium.The dispersing medium gives a pronounced difference for the ER effect.