Environmental Aging Effects on Thermal and Mechanical Properties of Electrically Conductive Adhesives

This paper investigates environmental aging effects on thermal and mechanical properties of three model electrically conductive adhesives (ECAs). A combination of several experimental techniques including thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and stress-strain dogbone testing has been utilized throughout this study. Samples were aged at 85°C, 100% RH for periods of up to 50 days and some of the samples were dried at 150°C after aging. Results obtained on aged samples with and without drying suggest that the conductive adhesive may have experienced both reversible and irreversible effects during environmental aging. Both plasticization that is reversible and further crosslinking and thermal degradation, which are irreversible, are indicated upon exposure of ECAs to the hot/wet environment.