Study On Preparation And Properties Of Multi-element Composite Silicone Rubber Dielectric Elastomer

Dielectric elastomer(DE)is a smart material that can transform mechanical energy into electrical energy and vice versa.Due to its good mechanical flexibility,easy processing,light weight and biocompatibility,DE has broad application prospects in the field of actuators.In order to make DE better used in this field,the preparation of a kind of DE with high dielectric properties,low elastic modulus and a large actuated strain under a small driving voltage has become a hotspot.The main chain of silicone rubber is composed of silicon and oxygen atoms alternately.Silicone rubber has excellent processing properties,electrical insulation and low cost,so it is an ideal dielectric elastomer material.In this paper,room temperature vulcanized silicone rubber(SR)and high temperature vulcanized methyl vinyl silicone rubber(MVSR)are used as matrix,and barium titanate(BT),titanium dioxide(TO),boron nitride(BN),zinc oxide(ZnO)are added to prepare various dielectric elastomer composites.In the third chapter of this article,composites such as SR/BT/BN,SR/TO/BN,SR/BT/ZnO,SR/TO/ZnO were prepared by solution blending method.The addition of BN and ZnO can improve the mechanical properties,dielectric properties and electric breakdown field of composites,and the effect of BN in improving the electric breakdown field of composites is more obvious.In the fourth chapter of this article,MVSR/BT,MVSR/BN,MVSR/BT/BN composites were prepared by mechanical blending method.MVSR/BT/BN composites can achieve higher electric break-down field.Several modifiers(stearic acid(SA),triton-X(Q),silane coupling agents(KH550,KH570,Si747,and Si69))were selected to modify BT.It was found that the mercapto groups of Si747 can react with the double bonds of MVSR,thereby increasing the interfacial interaction and improving the mechanical properties.The tensile strength and elongation at break of MVSR/30wt%BT-Si747/30wt%BN composite are 3.43 MPa and 2705%,which are 2.4 times and 4.4 times of MVSR/30wt%BT/30wt%BN,respectively.MVSR/BT-Si747/BN compo-sites show higher actuation performance under lower electric field due to simultaneous increase in dielectric constant and decrease in elastic modulus.The MVSR/10wt%BT-Si747/10wt%BN composite can obtain 8.81%actuated strain at 47.48 kV/mm,which is twice that of pure MVSR(4.4%at 60.21 kV/mm)In the fifth chapter of this paper,MVSR/TO and MVSR/TO/BN composites were prepared by mechanical blending method.The micro-nano combination of fillers was found to help improve the performance of composites.Therefore,four different particle size combinations of TO and BN(micro-micro(μμ),micro-nano(μn),nano-micro(nμ)and nano-nano(nn)combination)were designed respectively.The electric breakdown field of MVSR/10wt%μTO/10wt%μBN compo-site is 67.20 kV/mm,which is 12%higher than that of pure MVSR.When the mass fraction of the filler is high,the mechanical and electric breakdown properties of the micro-nano combination are far superior to those of the micro-nano combination and nano-nano combination.