Failure Analysis of Epoxy Resin Encapsulant During a Long-Term Storage.

In this article, the failure phenomena of softening and flow of crosslinked epoxy resin encapsulant during a long-term storage were analyzed by means of fault tree analysis, Fourier transform infrared spectroscopy, x-ray energy dispersive spectrum, and differential scanning calorimetry coupled with thermogravimetric analysis. Based on the results of those analyses, the reason of failure is identified to be that the epoxy resin was not cured completely during manufacturing, and the resulting imperfect three-dimensional crosslinked network was hydrolyzed because of the humidity in the environment during a long-term storage. Hence, the depolymerized polymers became softened gradually, and the seriously softened polymers flowed slowly because of creeping, an inherent property of the polymer materials. [ABSTRACT FROM AUTHOR]