Characterization of Linear Viscoelasticity Evolution of Epoxy Molding Compound Subjected to High Temperature Long Term Aging

Much of the electronics used to support power systems and enable safety systems resides underhood where operating temperatures are much higher than in traditional consumer applications. Underhood electronics may be subjected to sustained high temperature environment 150°C for long period of time during operation. However, there is insufficient information about the viscoelasticity of epoxy molding compound stored in sustained high temperature for long period of time. In this paper, two different types of epoxy molding compounds have been prepared and aged under two different temperatures: 100°C and 150°C. Multi-frequency scan dynamic mechanical analyzer (DMA) test has been conducted to study the viscoelasticity evolution from pristine, 40 days, 80 days, 120 days. The master curve has been obtained and the prony parameters of EMCs have been calculated. The aging effect of linear viscoelasticity has been discussed.

Linear Viscoelasticity: Review of Theory and Applications in Atomic Force Microscopy

Recently, much research has been performed involving the mechanical analysis of biological and polymeric samples with the use of Atomic Force Microscopy (AFM). Such materials require careful treatments which consider the rate-dependence of their viscoelastic response. Here, we review the fundamental theories of linear viscoelasticity, as well as their application to the analysis of AFM spectroscopy data. An outline of general viscoelastic mechanical phenomena is initially given, followed by a brief outline of AFM techniques. Then, an extensive outline of linear viscoelastic material models, as well as contact mechanics descriptions of AFM systems, are presented.