Viscoelastic behavior of filled silicone elastomers and influence of aging in inert and hermetic environment

Abstract

This article presents a series of experimental investigations on the viscoelastic behavior of silicafilled and silver-filled silicone rubber on the unaged and aged states. The study of specific aging conditions relative to the electronics industry is proposed in this work, namely aging in a hermetic, initially inert atmosphere, at high temperatures. Viscoelastic properties of the materials are measured through DMA tests. Strain sweep tests are carried for the characterization of unaged materials, and frequency sweeps at ambient temperature are performed to characterize the aging-dependent behavior. As a result of the experimental studies, an aging-dependent generalized Maxwell model is proposed in an attempt to describe the evolution in the behavior of silicones due to aging. Keywords Silicone rubber • Aging • Viscoelastic behavior • Material modeling 1 IntroductionSilicone rubber materials are long-established in the electronics industry. Silica-reinforced silicones, for instance, are widely used for both the assembly and the encapsulation of electronic devices, thanks to their interesting properties in terms of sealing and thermal stability [1]. Also, the last decades have seen the rise of electrically conductive silicone rubbers that, thanks to the addition of metallic fillers in high proportion (such as silver, copper and aluminum), are able to conduct electric signals. Electrically conductive adhesives are proved to have good mechanical strength and excellent electrical conductivity [2,3]. Therefore, they are adequate replacements for conventional assembly techniques in the electronics industry, as they are simpler and safer to implement than procedures like brazing and soldering [4,5].

Characterization of Potting Epoxy Resins Performance Parameters Based on a Viscoelastic Constitutive Model

“…A prevalent method for characterizing viscoelastic properties involves conducting uniaxial or shear relaxation modulus tests on materials [11,12]. Akshat Agha et al [13] utilized a dynamic thermo-mechanical analyzer to conduct shear tests on a one-component epoxy-based thermosetting adhesive to investigate viscoelasticity and plastic deformation of the material during thermal curing, developing a viscoelastic model to predict residual stresses generated in the adhesive.…”