The Preparation And Study Of Silicone Rubber Compcompositedielectric Elastomer

Due to their high dielectric constant,dielectric elastomers can produce large shapes or volume changes under the influence of an external electric field.As an elastomer material,it can be restored to its original state after the applied electric field is removed.There is a transformation from electrical energy to mechanical energy.Dielectric elastomers have great development prospects in smart actuators and sensors,especially biomedical materials,because of their good plasticity,high electrical deformation,high driving load,and high energy density.In order to make these materials better applied in these fields,the research on improving the dielectric properties,reducing the elastic modulus of the dielectric elastomer and obtaining a wonderful dielectric elastomer with large actuated strain on low electric field becomes a hotspot.In this study,the room temperature vulcanized silicone rubber(RTV107)was used as the matrix,and the inorganic particles(TiO2,BaTiO3)were used as the filler.The TiO2/RTV and BaTiO3/RTV composites were prepared by solution blending method.The effects of the mass fraction of the fillers on the mechanical and dielectric properties of the composites were investigated.It was found that the addition of TiO2 can significantly reduced the elastic modulus,improve the mechanical and dielectric properties of silicone rubber.The TiO2 and BaTiO3 particles were modified by various coupling agents(KH550,KH570,titanate coupling agent and fluorine coupling agent).As a result,we obtained a gain in actuated strain of 16%,which corresponds to an increase of about 167%in comparison with that of pure silicone rubber.We used in-situ polymerization method to obtain the core-shell structure of TiO2@PANI and BaTiO3@PANI filler with different PANI shell thickness by changing the reaction time.Then the TiO2@PANI and BaTiO3@PANI/silicone rubber composites were prepared.The effects of different PANI thickness in TiO2@PANI and BaTiO3@PANI core-shell structured fillers on the properties of composites were investigated.The PANI modified fillers can greatly improve the dielectric and mechanical properties of the composites.The actuated strain was greatly improved,and a large actuated strain can be obtained at a low voltage.The nm-TiO2@PANI-2h/silicone rubber composite obtained the maximum actuated strain of 11%under the electric field of 34 kV/mm,and increased by 5.8 times compared with pure silicone rubber(1.9%)at the same voltage.Finally,to improve the breakdown strength of the nm-TiO2@PANI-2h/silicone rubber composite,we modified the nm-TiO2@PANI-2h by different concentrations of PVP solution to form the nm-TiO2@PANI-2h@PVP.The breakdown strength of nm-TiO2@PANI-2h@PVP-3/silicone rubber composite reached to 52 kV/mm,which was 52.9%higher than the nm-TiO2@PANI-2h/silicone rubber composite.