Prepaeation And Research Of High Dielectric Low Loss Dilicone Rubber-based Dieletric Elatomer Composites

Dielectric elastomer,as a typical electroactive polymer material,can undergo certain deformation under an external electric field and convert electrical energy into mechanical energy.This process is reversible when the electric field is removed.It has very broad prospects in the fields of drivers,generators and sensors.Silicone rubber has a very good application prospect because of its wide temperature range,high conversion efficiency,and fast response speed.However,due to the non-polar structure of the silicone rubber matrix,its dielectric constant is low,which limits its further development.In this paper,physical doping and chemical modification methods were used to prepare a silicone rubber-based dielectric elastomer with high dielectric loss and good mechanical properties.The main research contents and results are as follows.1.Dopamine(DA)modified carbon nanotubes(MWCNT)and polydimethylsiloxane(PDMS)were blended to prepare MWCNT-DA/PDMS composite materials.Dopamine was used to modify the carboxylated carbon nanotubes,and composite materials with different contents of filler molecules were prepared by physical doping.The structure of MWCNT-DA was characterized by infrared spectroscopy,Raman spectroscopy,and thermal weightlessness.The characterization of transmission electron microscopy showed that the modified MWCNT-DA agglomeration phenomenon had improved.Compared with,MWCNT-DA has a better dispersion in the PDMS matrix,and the interface with the matrix is enhanced.The composite material is tested by a universal testing machine and a dynamic thermomechanical analyzer.The results show that the modified MWCNT-DA/PDMS elongation at break has increased.According to the analysis of dielectric properties,when the content of MWCNT-DA is 3wt%,the dielectric constant of MWCNT-DA/PDMS composite is 5.9,which is nearly 1.7 larger than that of pure PDMS.Times,and the loss is still very low,only 0.002.At the same time,the mechanical and electrical properties of the composite material have improved after modification,and the electro-induced deformation has increased.2.Cyano chemically modified vinyl silicone rubber dielectric elastomer.By adjusting the ratio of vinyl silicone oils with different viscosities,a vinyl silicone rubber matrix with good performance was prepared.The atomic force microscope,thermal weight loss analysis and cross-link density analysis showed that when the ratio of 8Wcs vinyl silicone oil to 2Wcs vinyl silicone oil was 2:1 At this time,the vinyl silicone rubber matrix is cured the most.Propylene dimethoxysilane(ADS)and allyl cyanide(AC)were synthesized into a small molecule polar chain(ADS@AC)and attached to the vinyl silicone rubber matrix.The structure of ADS?AC was characterized by NMR.Dielectric performance analysis shows that,because the cyano group in ADS@AC acts as a polar group,the number of dipoles in the material increases and the polarizing ability increases.Therefore,when the amount of ADS@AC added is 20%,the ADS@AC/SR The dielectric constants were increased to 7.05.At the same time,the dielectric loss is kept at a low level around 0.01.Moreover,the modulus of the material is reduced,and the electromechanical performance is improved.When the addition amount is 20%,the electro-deformation of the material is the largest.