Preparation And Properties Study Of Silicone Rubber-based Dielectric Elastomer

Intelligent material plays an important role in today’s social development.It is a kind of material that can respond to the stimulation of light and electricity.Intelligent materials generally have one or more functions,such as sensing,response,information processing,feedback,self-healing and so on.Their existence greatly facilitates our lives and improves our quality of life.Dielectric elastomer is a kind of intelligent material.It can change the shape and volume under the stimulation of electric field,and can restore the original state after the electric field is cancelled,so that the mutual conversion between electrical energy and mechanical energy can be realized.Dielectric elastomers are mainly used in actuators,generators,sensors,flight rudders and solid-state aircraft,and are also ideal materials for artificial muscles.When the dielectric elastomer is used as a driver,the electrical deformation performance is an important measurement standard,and the electric breakdown strength determines the upper limit of the electrical deformation performance.Although the improvement of the electrical deformation performance of the dielectric elastomer has been widely studied,few studies can improve the electrical deformation performance and the electrical breakdown performance at the same time,so the research can improve the electrical deformation performance and electrical breakdown field strength properties of materials at the same time are critical.In this paper,SR/BT composites were prepared by adding high dielectric permittivity barium titanate(BT)fillers to silicone rubber(SR).The effects of barium titanate fillers on the mechanical,dielectric,driving and electrical breakdown properties of SR were studied.We found that barium titanate is generally dispersed in pure silicone rubber matrix,and then we modified barium titanate with polyvinylpyrrolidone(PVP)as modifier,and then mixed with silicone rubber matrix to prepare composite(SR/BT@PVP).The SEM results show that the packing of barium titanate coated with PVP is well dispersed in the silicone rubber,and compared with SR/BT composite with the same filler fraction,the electrical deformation performance and electrical breakdown field strength performance are improved,among which the electrical deformation performance is the best when 10%BT@PVP is added.Later,we chose silane coupling agents(KH550,KH560,KH570)to modify barium titanate according to the principle of "similar phase solubility".The silane coupling agent has a-Si-O-structure similar to SR,which can effectively improve the interface binding force between BT and SR matrix.Therefore,we compared the mechanical,dielectric and electrical deformation properties of the composite(SR/10%BT@PVP,SR/10%BT@KH550,SR/10%BT@KH560,SR/10%BT@KH570)prepared by blending 10%modified fillers(BT@PVP,BT@KH550,BT@KH560,BT@KH570)with SR,and found that SR/10%BT@KH550 has the best electrical deformation and electrical breakdown field strength properties.In this paper,4-chlorophenyl alcohol was grafted onto the crosslinker TEOS by dealcoholization and condensation reaction,and then the crosslinker modified by dipole was crosslinked with polydimethylsiloxane to synthesize a new type of dipolar silicone rubber(SRCl).The results of FTIR,DSC and XRD show that 4-chlorophenyl alcohol dipoles have been successfully grafted into silicone rubber,and the actual grafting amount is obtained through TG test.The tensile test shows that the introduction of dipoles can improve the mechanical properties to a certain extent.The dielectric test shows that with the increase of the grafting amount of dipoles,the dielectric permittivity increases gradually and the dipoles relaxation phenomenon appears.At the same time,the electrical deformation property and electric breakdown field strength of the dipolar silicone rubber are greatly improved.In this paper,a new type of dipolar silicon elastomer(SRCl)is compounded with 10%BT or 10%modified BT fillers(BT@PVP,BT@KH550,BT@KH560,BT@KH570).The relationship between different fillers and new dipolar silicone rubber was studied.The mechanical properties,dielectric properties and electrical deformation properties of the composite were tested.The electrical deformation properties of all SRCl based composites were improved compared with those of SR based composites.At the same time,it is found that SRCl/BT has the best mechanical properties in SRCl based composite.It is speculated that the existence of modifier is not conducive to the combination of filler and SRCl.In view of this,a series of different content of BT and SRCl were compounded(SRCl/BT),and mechanical tests were carried out.It was speculated that hydrogen on the surface hydroxyl of BT had electrostatic effect on chlorine on SRCl,and SRCl/BT had excellent electrical deformation and electrical breakdown properties.