Moisture diffusion into aluminum powder-filled epoxy adhesive in sodium chloride solutions

The objective of this study was to shed light on the influence of metal fillers on water/moisture sorption characteristics of adhesives. For that purpose, epoxy adhesive was filled by aluminum powder at four different contents (0, 10, 25 and 50 wt%). Water and fluid immersion tests were utilized to determine the moisture sorption behavior of aluminum powder-filled epoxy adhesive under complete immersion in distilled water and NaCl solutions. It was observed that the adhesives adsorb a larger amount of water upon exposure to distilled water than when exposed to different sodium chloride solutions. The moisture diffusion rate in the adhesive immersed in a test solution is, however, proportional to the salt concentration of the solution. It was also determined that there is no significant effect of aluminum filler content on moisture diffusivity in epoxy adhesive specimens while the addition of aluminum filler into epoxy decreases the total amount of water intake at saturation.