Electric memory effects in styrene-butadiene rubber, containing electric inclusions of highly aromatic oil

Abstract

It was determined that samples of styrene-butadiene rubber (SBR), containing highly aromatic oil, exhibit memory effects giving rise to dynamic elastic modulus, damping and internal stresses degree which can be tailored depending on the applied electric field strength. The capability and stability of the interaction process between aligned neighbor dipoles for exhibiting a memory effect, once the aligning electric field was removed are studied. It is determined that depending on the spatial arrangement and the amount of electric charge of the dipoles, this interaction is able to promote a memory effect which keeps the alignment between them. This electrostatic interaction plays the role of a counteracting effect for keeping the alignment, which was called electroelasticity. The results from the developed model were applied successfully to SBR composite samples for explaining the memory effects recorded from dynamic mechanical analysis (DMA) measurements under electric field. In addition, the model of the electric inclusion based on the inclusion theory for continuous media, was applied to determine the degree of internal stresses in the dielectric composite material due to the external applied electric field. In addition, from the coupling between the model developed here and simple issues related to the mechanical properties of composite materials, a procedure for determining the maximum possible gap between the electric dipoles in composite dielectric materials is also shown.