Diffusion of Moisture

The rate of diffusion of moisture through an adhesive can be derived from mass uptake measurements on bulk samples of adhesive. From this, the change in concentration profile with time can be predicted for an adhesive joint based on Fickian behaviour. The presence of moisture not only affects the adhesive properties but may also result in loss of adhesion and failure at the interface in a joint. MERL uses its environmental ovens and pressure cells to accelerate diffusion measurements to enable the estimation of long term diffusion of moisture into and out of an adhesive layer.