The Preparation And Study Of Silicone Dielectric Elastomer Composites

Dielectric silicone elastomer composites have the merits of lowmodulus, high dielectric constant, high elastic energy density, fastresponse speed and good process ability, so they enjoy the most commonresearch in the dielectric elastomer field. The composites of silicone/TiO₂and silicone/PEG were fabricated. Then the influence of TiO₂and PEG onthe dielectric, electric, mechanical and electromechanical properties ofsilicone composites was tested. The details are as followed:1. The composites composed of silicone（DC3481） and three types ofTiO₂（micro rutile, Nano rutile and Nano mixed） were fabricated throughroom temperature vulcanization method. First,30phr of the three types ofTiO₂were added in silicone separately. Both the dielectric constant andthe Young modulus of the resulted three kinds of composites were higherthan them of the pure silicone. The dielectric constant of rutile TiO₂washigher than it of the mixed TiO₂, so the dielectric constant of thesilicone/μ-TiO₂and silicone/n-TiO₂composites was higher than it of thesilicone/mixed-TiO₂composite. And it was80%higher than it of the pure silicone. The Young modulus of silicone/μ-TiO₂was lower than it of thesilicone/n-TiO₂and silicone/mixed-TiO₂composites, so the figure ofmerit of silicone/μ-TiO₂was the highest of the three kinds of compositesand pure silicone. And it had the actuated strain of18%at50v/μm,50%higher than it of the pure silicone.Than10,20, and30phr μ-TiO₂were added to silicone, and theinfluence of loading fraction of μ-TiO₂on electric, dielectric, mechanical,and electromechanical properties were tested. Both the dielectric constantand the modulus of the composite increased with addition of μ-TiO₂. Thefigure of merit of the composite composed of silicone and30phr μ-TiO₂was the highest, so its actuated strain was the highest. A comparisonbetween the theoretical strain and the actuated strain was made, and thedifference and relationship was discussed.2. The composites composed of silicone（DC3481） and PEG600andPEG1500were fabricated through room temperature vulcanization. First,5phr PEG600and PEG1500were added to silicone. The dielectricconstant of the two kinds of composites was higher than the pure silicone.Specially, the dielectric constant of silicone/PEG1500composite was thehighest and50%higher than the pure silicone. The Young modulus of thepure silicone was lower than silicone/PEG1500and higher thansilicone/PEG600composite. It is because that PEG600was liquid havingplasticization effect and PEG1500had semi-crystalline structure reinforcing the silicone. The figure of merit of silicone/PEG600was thehighest resulting in the highest actuation strain.Than composites composed of silicone and2,5,8phr PEG600weremade. The influence of loading fraction of PEG600on the electric,dielectric, mechanical and electromechanical properties was studied. Withthe addition of PEG600, the dielectric constant increased, the modulusdecreased and the actuated strain increased steadily. At the same time,the breakdown strength decreased because of decreased resistivity.Beyond that, a comparison of the theoretical strain and actuated strainwas made, and the relationship between actuation strain and the dielectric,mechanical properties was discussed.