The Dielectric And Electroactive Strain Properties Of Acrylic Resin Elastomer Based Composite Films

Dielectric elastomer (DE), a type of electroactive polymer, is a material that can transformelectric energy directly into mechanical work. In actuated state under the effect of electric field, theshape of the DE film would change. When the electric field is removed, the shape of the DE filmwould come back to its original state. Based on its features, the DE films can be used in both actuationand power generation areas, such as, artificial muscles, sensors, generators and so on. Dielectricconstant and elastic modulus are the important factors that would affect the actuation performance ofthe DE films. Besides, pre-strain, electrodes and electric field are also important. Researching intothese factors to find the most suitable conditions would be of great value to the applications of DE.In this work, a high dielectric constant nanocomposite ACM-g-CuPc was fabricated, of whichcopper phthalocyanine (CuPc) oligomer was grafted onto the backbone of acrylic resin elastomer(ACM). FT-IR,1H-NMR and ICP tests confirmed the success of the graft reaction. The graftedcomposite exhibits several benefits over the physical blended one. Transmission electron microscope(TEM) micrographs indicate that the size of grafted CuPc is in the range of15~30nm, which is morethan30times smaller than that of the simply blended one (500nm). DSC and TGA test shows that theparticipation of CuPc increased the thermal stability of the grafted composite.The dielectric constant and dielectric loss of the ACM-g-CuPc increase with frequency as well asthe content of CuPc. Compare with the simply blended composite ACM/CuPc, ACM-g-CuPc has alower dielectric loss and a higher breakdown field. At room temperature, the dielectric constant ofACM-g-CuPc (with15wt%CuPc) reaches303at100Hz, which is60times higher than the pureACM and1.5times higher than ACM/15%CuPc. The remarkable enhancement in dielectric responsecan be attributed to the greatly strengthened exchange coupling effect and theMaxwell-Wagner-Sillars polarization mechanism. In addition, the dielectric properties of thecomposites were changed after the irradiation of60Co, and the irradiation factor has a larger effect onthe dielectric properties of ACM/CuPc than that of ACM-g-CuPc. The elastic modulus ofACM-g-CuPc decreased with the increasing BA content and increased with the increasing CuPccontent. The grafted composite with70wt%BA has a elastic modulus of1.1MPa. Besides, the elasticmodulus of ACM/5%CuPc is higher than that of ACM-g-5%CuPc.In plane direction, the electric field induced strain of ACM-g-CuPc increased with the decreasingmodulus and increasing passive area. Moreover, the higher equal biaxial pre-strain that the film had, the larger induced strains, breakdown field and response speed that the film could achieve. Whenusing the carbon grease as electrodes, the diameter of which is1cm, the in-plane electric fieldinduced strain of ACM-g-5%CuPc (60wt%BA) with150%150%equal biaxial pre-strain is as highas24%under10MV/m. Furthermore, the factors such as pre-strain, passive area and so on also havean effect on the failure behavior of the ACM-g-CuPc.